GOST 4974 method a edition. The shelf life of the solution is not limited

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It applies to drinking water, including packaged in containers, and water from underground and surface sources of drinking water supply and establishes photometric methods for determining the content of manganese in the range of mass concentrations from 0.01 to 5.00 mg / dm3. using: - oxidation of manganese compounds to permanganate ions after removing the interfering effect of chloride ions (method A); - the formation of a colored compound with formaldoxime (method B). If the mass concentration of manganese exceeds 5 mg / dm 3, then the analyzed sample is diluted with distilled water, but not more than 100 times. The methods provide comparable results.

Replaces GOST 4974-72 “Drinking water. Methods for determining the content of manganese "IUS 10-2015

1 area of use

3 Sampling

4 Requirements for measurement conditions

5 Measuring instruments, auxiliary equipment, reagents, materials

6 Determination of manganese content using oxidation to permanganate ions (method A)

7 Determination of manganese content using formaldoxime (method B)

Bibliography

This GOST is located in:

Organizations:

20.10.2014	Approved	Interstate Council for Standardization, Metrology and Certification	71-P
11.11.2014	Approved	Federal Agency for Technical Regulation and Metrology	1539-st
	Published by	Standardinform	2015 g.
	Designed by	Lumex Marketing LLC
	Designed by	LLC Protector

Drinking water. Determination of manganese content by photometric methods

GOST 17.1.5.05-85Protection of Nature. Hydrosphere. General requirements for sampling surface and sea waters, ice and atmospheric precipitation
GOST 6709-72Distilled water. Technical conditions
GOST 10652-73Reagents. Disodium salt of ethylenediamine-N, N, N ", N" - tetraacetic acid, 2-aqueous (Trilon B). Technical conditions
GOST 10733-98Mechanical watches and pocket watches. General specifications
GOST 10929-76Reagents. Hydrogen peroxide. Technical conditions
GOST 1277-75Reagents. Silver nitrate. Technical conditions
GOST 14919-83Household electric stoves, electric stoves and ovens. General specifications
GOST 1625-89Technical formalin. Technical conditions. Replaced by GOST 1625-2016.
GOST 1770-74Laboratory glassware. Cylinders, beakers, flasks, test tubes. General specifications
GOST 195-77Reagents. Sodium sulfate. Technical conditions
GOST 19908-90Crucibles, bowls, beakers, flasks, funnels, test tubes and tips made of transparent quartz glass. General specifications
GOST 20478-75Reagents. Ammonium persulphate. Technical conditions
GOST 23350-98Wrist and pocket electronic watches. General specifications
GOST 24147-80High purity water ammonia. Technical conditions
GOST 25336-82Laboratory glassware and equipment. Types, main parameters and dimensions
GOST 26272-98Electronic-mechanical quartz wrist and pocket watches. General specifications
GOST 29227-91Laboratory glassware. Graduated pipettes. Part 1. General requirements
GOST 3760-79Reagents. Ammonia water. Technical conditions
GOST 4146-74Reagents. Potassium persulphate. Technical conditions
GOST 4204-77Reagents. Sulfuric acid. Technical conditions
GOST 4208-72Reagents. Salt of ferrous oxide and ammonium double sulfate (Mohr's salt). Technical conditions
GOST 4328-77Reagents. Sodium hydroxide. Technical conditions
GOST 4461-77Reagents. Nitric acid. Technical conditions
GOST 4523-77Reagents. Magnesium sulfate 7-water. Technical conditions
GOST 4919.1-77Reagents and highly pure substances. Methods for preparing solutions of indicators. Replaced by GOST 4919.1-2016.
GOST 5456-79Reagents. Hydroxylamine hydrochloride. Technical conditions
GOST 6552-80Reagents. Orthophosphoric acid. Technical conditions
GOST 9147-80Porcelain laboratory utensils and equipment. Technical conditions
RMG 76-2004State system for ensuring the uniformity of measurements. Internal quality control of the results of quantitative chemical analysis. Replaced by RMG 76-2014.
GOST ISO / IEC 17025-2009General requirements for the competence of testing and calibration laboratories. Replaced by GOST ISO / IEC 17025-2019.
GOST 31861-2012Water. General requirements for sampling
GOST 31862-2012Drinking water. Sample selection
GOST OIML R 76-1-2011State system for ensuring the uniformity of measurements. Scales of non-automatic operation. Part 1. Metrological and technical requirements. Testing
GOST R 56237-2014Drinking water. Sampling at water treatment plants and pipeline distribution systems

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INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

TIN-ZINC BRONZE BARS

Technical conditions

Official edition

Standardinform

Foreword

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic provisions "and GOST 1.2-97" Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for Development, Acceptance, Application, Update and Cancellation ".

Information about the standard

1 DEVELOPED by the Technical Committee for Standardization TK 106 "Tsvetmetprokat", Research, Design and Engineering Institute of Alloys and Processing of Nonferrous Metals "Open Joint Stock Company" Institute Tsvetmetobrabotka "(JSC" Institute Tsvetmetobrabotka ")

2 SUBMITTED by the Technical Secretariat of the Interstate Council for Standardization, Metrology and Certification

3 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification (minutes of November 14, 2014 No. 72-P)

4 By order of the Federal Agency for Technical Regulation and Metrology dated November 26, 2014 No. 1829-st, the interstate standard GOST 6511-2014 was put into effect as a national standard of the Russian Federation from September 1, 2015.

Information about changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notice and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

In the Russian Federation, this standard cannot be fully or partially reproduced, replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology.

Appendix B (mandatory)

Method of ultrasonic testing of press sinkers

The technique is intended for ultrasonic testing in order to detect and determine the place of the end of the press bite in pressed rods of non-ferrous metals and alloys with a diameter of 10 mm or more using ultrasonic flaw detection tools with a contact method of inputting ultrasonic vibrations from the cylindrical surface of the product.

B.1 Apparatus and reference materials

B.1.1 For control, use: devices for scanning with built-in separately-aligned or with direct aligned ultrasonic transducers; Ultrasonic flaw detector, standard samples; auxiliary devices and devices for ensuring constant control parameters (angle of entry, acoustic contact, scanning step).

B.1.2 It is allowed to use any ultrasonic flaw detector in conjunction with sensors that provide sufficient sensitivity, the value of which is set by setting according to a standard sample.

B.1.3 A standard sample for adjusting the sensitivity of ultrasonic equipment during testing is a section of a defect-free rod 300 mm long with a diameter of 100; 60; 40; 25 mm, made of the same material as the inspected bar, or a material with similar acoustic properties and having the same surface quality as the inspected bar.

B.1.5 The section of the product from which the standard sample is made should not have internal defects of metallurgical origin, which could have been detected by the ultrasonic method when setting the flaw detector to the highest real sensitivity.

B.1.6 The state of the outer surface of the standard sample should be no worse than the controlled items.

B.1.7 The standard sample must have a certificate approved by the head of the enterprise.

B.2 Preparation for control

B.2.1 Before testing, the rods should be cleaned of dirt, dust, oils and other contaminants.

B.2.2 Connecting the flaw detector to the network and working with it is carried out in accordance with the technical description and operating instructions for the flaw detector used for testing.

B.3 Monitoring

B.3.1 Quality control of the metal continuity of the bars is based on the use of the echo method.

B.3.2 The introduction of ultrasonic vibrations into the metal of the bar is carried out by the contact method.

B.3.3 Inspection of the metal of the bar for the absence of defects is achieved by scanning the surface of the inspected bar with an ultrasonic beam. The control place should be convenient and provide free access around the circumference to the controlled end of the bar.

B.3.4 Control is carried out starting from the rear end of the pressed bar. The temperature of the controlled bar should be no higher than 40 0 С.

B.3.5 When checking, it should be taken into account that the press-sink in the bars has an elongated shape and different orientations of the reflecting surfaces in relation to the generatrix and is most often located close to the end of the bar, therefore, its detectability from different parts of the surface can be different.

B.3.6 For mechanized scanning of the sensor over the surface of the controlled bar, it is recommended to use roller, prismatic or other devices with built-in ultrasonic sensors.

B.3.7 Bars with a diameter of less than 60 mm are monitored at an ultrasonic frequency of 5 MHz, and rods with a diameter of more than 60 mm - at an ultrasonic frequency of 2.5 MHz. When determining the location of the end of the press bite in bars made of a material with elastic anisotropy with a coarse-grained structure, it is recommended to use lower frequencies.

B.3.8 During the inspection, the device for scanning is installed on the controlled end of the bar and the sensor is tightly pressed to its surface, while the bottom echo signal should appear on the flaw detector screen. With the appearance of the bottom echo, the scanning device begins to move around the circumference and along the bar.

B.3.9 The scanning speed of the sensor along the surface of the bar is selected on the basis of the conditions for obtaining reliable acoustic contact; it should not exceed 0.5 m / s in automated devices and 0.15 m / s in manual scanning.

B.3.10 The correctness of the flaw detection equipment adjustment is checked at least once within 2 hours of device operation using a standard sample.

B.3.11 When moving the sensor along and around the bar, it is necessary to follow the flaw detector screen for the presence of an acoustic contact. A stable back-wall echo indicates a satisfactory ultrasonic probe insertion into the bars. If the echo signal disappears with a working sensor and the correct setting of the equipment, then the reliability of the acoustic contact is checked by

increasing the supply of couplant and wiping the surface of the bar with a rag.

B.3.12 After detecting the press sink, the sensor is moved along the bar in order to determine the length of the press sink and the place of its end. In the area where there is a complete disappearance of the additional echo signal to the left of the back reflection, by rotating the device for scanning around the bar, one is convinced of the end of the press bracing along the entire circumference of the bar.

B.3.13 Having determined with the help of ultrasound the exact place of the end of the press-tightening, a well-visible mark is applied to the product along the circumference of the bar to cut it.

B.3.14 When testing alloys with an elastically inhomogeneous coarse-grained structure, it is necessary to carefully control the rear end of the bar, where the structural interference is lower and the bottom echo is stable. Against the background of unstable structural interferences, the location of the echo signal from the press bite is noticed on the flaw detector screen. Moving the scanning device along the bar, they continuously observe the echo signal from the press bite, which, in contrast to structural interference, is stable.

B.4 Evaluation of results

B.4.1 Evaluation of the solidity of the metal of the bars is carried out according to the results of the analysis of information.

B.4.2 The presence of a press sink is judged by the appearance of an additional echo signal to the left of the back reflection.

B.4.3 The disappearance of an additional echo signal to the left of the back reflection indicates the end of the press-sinking.

UDC 669.6'5-422: 006.354 MKS 77.150.30

Key words: rods of tin-zinc bronze, nominal diameter, grades, chemical composition, curvature, mechanical properties

Signed for printing on 03/02/2015. Format 60x84V 8.

Uel. print l. 1.86. Circulation 38 copies. Zach. 725.

Prepared on the basis of the electronic version provided by the developer of the standard

FSUE "STANDARTINFORM"

123995 Moscow, Granatny per., 4. www.gostinfo.ru [email protected]

M E F G O COURT A R S T V E N N Y Y

STANDARD

TIN-ZINC BRONZE Specifications

Wrought tin-zinc bronze rods. Specification

Date of introduction - 2015-09-01

1 area of use

This standard applies to drawn rods of round, square and hexagonal cross-sections and extruded rods of circular cross-section of tin-zinc bronze used in various industries.

The standard establishes the assortment, technical requirements, acceptance rules, control and test methods, marking, packaging, transportation and storage of bars.

2 Normative references

This standard uses normative references to the following interstate standards:

The same, drawn, round, of normal manufacturing accuracy, solid, 12 mm in diameter, unmeasured length, for processing on automatic machines made of bronze brand BrOTs 4-3

The same, pressed, round, with a diameter of 60 mm, of unmeasured length made of bronze grade BrOTs 4-3 Bar GKRHKh 60 ND BrOTs 4-3 GOST 6511-2014

The same, drawn, square, high-precision manufacturing, 10 mm in diameter, of unmeasured length, made of BROTS 4-3 bronze, in free-wound coils:

If special conditions are not specified in the order by the consumer, then the rods are made with the performance conditions at the discretion of the manufacturer.

5 Technical requirements

5.1 Bars are manufactured in accordance with the requirements of this standard for technological regulations, approved in the prescribed manner.

5.2 Bars are made of bronze grade BrOTs 4-3 in accordance with GOST 5017.

5.3 The surface of the bars should be free from contamination that hinders visual inspection, without cracks, delamination, nicks, scratches and scale.

On the surface, separate captivity, dents, shells are allowed,

risks, seizure marks and other defects, as well as ringing, traces of straightening, if during control cleaning they do not bring the rods beyond the maximum deviations in diameter.

5.4 Internal defects in the form of cavities, non-metallic inclusions and press-weights are not allowed in the bars.

Broken end of the bar after removing the press-tightening method

kinks are not cut off when dispatched to the consumer.

5.5 At the request of the consumer, the rods must be evenly cut on both sides. The cut should be perpendicular to the bar axis.

5.6 If the consumer does not specify the shape of the ends of the rods with a diameter of 15 mm or less, it is allowed to chop off, while the oblique cut is not regulated.

5.7 Deviation from the cross-sectional shape is allowed within the diameter tolerance.

5.8 Square and hexagonal rods should not have twisting visible to the naked eye.

5.9 Bars should be straightened. The maximum curvature of rods per 1 m of length should not exceed the values indicated in table 3.

Table 3 - Maximum curvature of bars

Method of making rods	Maximum curvature of a bar per 1 m of bar length at a nominal diameter or distance between parallel sides of a bar, mm
Method of making rods	up to 18 incl.	St. 18 to 40 incl.

Drawn for processing on automatic machines
Pressed

5.10 The total curvature of the bar should not exceed the product of the value of the permissible curvature by 1 m by the total length of the bar in meters.

Curvature is not set:

For rods made in coils.

5.11 The mechanical properties of the bars must comply with the requirements specified in table 4.

Table 4 - Mechanical properties of bars

making	Nominal diameter or distance between parallel faces, mm	Ultimate tensile strength sb, MPa (kgf / mm2), not less	Elongation after rupture,%, d 5 not less
	From 5 to 12 inclusive
	Sv 12 to 25 inclusive
	Sv 25 to 35 inclusive
	Sv 35 to 40 inclusive
Pressed	From 42 to 120 inclusive

At the request of the consumer, drawn rods with a diameter of 5 to 15 mm inclusive must be tested for bending, while they must withstand, in a cold state, without the appearance of tear marks and without delamination, a 90 ° bend around the mandrel with a radius of curvature equal to the diameter of the bar.

6 Acceptance rules

6.1 Bars are accepted in batches. A batch should consist of bars of the same alloy grade, one section shape, one size, one manufacturing method, one material condition, one manufacturing accuracy. The batch must be completed with one quality document containing:

Trademark or name and trademark of an enterprise

manufacturer;

The legal address of the manufacturer and (or) the seller;

Test results (at the request of the consumer);

Batch number;

The mass of the party.

The mass of the batch should be no more than 2000 kg.

It is allowed to draw up one quality document for several batches of bars shipped simultaneously to one consumer.

6.2 Checking the dimensions and quality control of the surface of the bars are subjected to each bar of the batch.

6.3 To check the curvature, take at least three rods or three bundles from 2000 kg or less.

6.4 Checking for the absence of a press bite at the end of the bar adjacent to the press residue is carried out on each pressed bar.

6.5 To check the fracture of the drawn bars, two bars are taken from the batch.

6.6 For tensile and flexural tests, select two rods from each lot.

6.7 To check the chemical composition, select two rods, two bundles or two coils from 2000 kg or less. The manufacturer is allowed to check the chemical composition on a sample taken from the molten metal.

6.8 Upon receipt of unsatisfactory test results for at least one of the indicators, in addition to the surface quality, a repeated test is carried out on it on a double sample taken from the same batch.

The results of repeated tests are valid for the entire batch.

7 Methods of inspection and testing

7.1 Inspection of the surface of the bars is carried out without the use of magnifying devices.

7.2 Checking the dimensions is carried out on each selected bar or coil according to 6.2 and on 10% of the bars in each bundle.

7.3 Control of the diameters of drawn bars is carried out with a micrometer in accordance with GOST 6507, diameters of pressed bars - with a caliper in accordance with GOST 166.

The length of the bars is measured with a tape measure in accordance with GOST 7502 or a metal ruler in accordance with GOST 427.

7.4 Twisting, curvature, oblique cut, deviation from the shape of the cross-section of the bars are measured in accordance with GOST 26877.

It is allowed to use other measuring and control instruments that provide the required accuracy.

7.5 Checking for the presence of internal defects and the absence of a press-tightening in the pressed bars is carried out at the end of the bar adjacent to the press-residue, by a non-destructive test method according to the method described in Appendix B, or by the fracture method. In the fracture of the bars, there should be no press sinkers, cavities, non-metallic inclusions. A fracture during the delivery of the bars is not cut off.

Control for the presence of cavities and non-metallic inclusions is carried out according to the manufacturer's method.

7.6 Checking drawn bars for the presence of internal defects is carried out by the fracture method. Both ends of the bar are checked.

In the fracture of the bars, there should be no press bumps, cavities, non-metallic inclusions. Kink at delivery of bars is not cut

7.7 To check the metal for internal defects by fracture, the rods should be notched on one or both sides.

7.8 The notch shall be made in such a way that the fracture passes through the center of the bar.

The width of the break should be:

Not less than 6 0% of the diameter - for rods with a diameter up to 16 mm inclusive;

Not less than 10 mm - for rods with a diameter of more than 16 mm.

Inspection of the fracture is carried out visually without the use of magnifying devices.

7.9 Sampling for tensile testing is carried out in accordance with GOST 24047.

It is allowed for bars with a cross-sectional area of up to 120 mm 2 to grind specimens with a diameter of 6.0; 8.0; 10.0 mm from the center of the bar.

The tensile test is carried out in accordance with GOST 1497.

7.10 To check the chemical composition, take one sample from each selected by

6.7 rods or coils and one sample from each selected bundle. Sampling and preparation of samples for chemical analysis is carried out in accordance with GOST 24231.

The chemical composition of the rods is determined according to GOST 1953.1-GOST 1953.16 or other methods that are not inferior in accuracy to standard ones.

If disagreements arise in assessing the quality, the chemical composition of the rods is determined according to GOST 1953.1 - GOST 1953.16.

7.11 The manufacturer is allowed to apply other test methods that provide the required accuracy specified in this standard.

7.12 In case of disagreements in assessing the quality of bars, the consumer and the manufacturer are guided by the requirements established by this standard.

8 Marking, packaging, transportation and storage

8.1 Each bundle or coil should be affixed with a metal, cardboard or plywood tag indicating:

Trademark or name and trademark of the manufacturer;

Country of origin;

Conventional designation of bars;

Batch number;

Inspection stamp or controller number.

At the end of rods with a diameter of more than 40 mm, the following should be knocked out:

Alloy grade or conventional designation of the alloy grade;

Batch number;

Brand of technical control.

8.2 Bars are delivered unpacked.

8.3 Bars with a diameter of 5 to 40 mm are tied into bundles or coils weighing not more than 80 kg each. Each bundle must consist of at least three rods and must be tied with a wire in two turns with a diameter of at least 1.2 mm in accordance with GOST 3282 in at least two places so that mutual movement of the rods in the bundle is excluded. The ends of the wire are connected by twisting at least five turns. Each coil must be tied with wire in accordance with GOST 3282 in at least three places evenly around the circumference of the coil.

A bunch of bundles is allowed using a packing tape with a cross-section

8.4 By agreement between the manufacturer and the consumer, the mass of beams and coils is more than 80 kg for mechanized loading and unloading.

8.5 Bars up to 35 mm in diameter weighing more than 25 kg each, as well as rods with a diameter of more than 35 mm are not bundled into bundles.

On the ends of rods with a diameter of more than 35 mm and the lateral part of rods with a diameter of 35 or less, not tied into bundles, the following shall be stamped: the trademark of the manufacturer and the alloy brand.

For marking bars, it is allowed to use the letter designation "BOTS"

8.6 At the request of the consumer, drawn rods with a diameter of up to 10 mm inclusive of high and increased manufacturing accuracy, tied in bundles or coils, are packed in synthetic or nonwoven materials in accordance with regulatory documents, ensuring the preservation of the quality of the rods.

8.7 Bars are transported by all types of transport in covered vehicles in accordance with the rules for the carriage of goods in force for this type of transport.

8.8 Transport marking - in accordance with GOST 14192 with additional inscription of the batch number.

8.9 Bars should be stored in covered rooms and protected from mechanical damage, moisture and active chemicals.

9 Manufacturer's warranty

9.1 The manufacturer guarantees the compliance of the bars with the requirements of this standard, provided that the consumer observes the conditions of transportation and storage.

Appendix A (informative)

Diameters, cross-sectional area and linear density of drawn and extruded bars

Table A.1

Nominal diameter, mm	Cross-sectional area of bars, mm 2			Theoretical weight of 1 m of rods, kg
Nominal diameter, mm		square	hex		square	hex

Note - When calculating the theoretical mass, the density of bronze is taken to be 8.8 g / cm a.

Interstate standard GOST 4974-2014

"DRINKING WATER. DETERMINATION OF MANGANESE CONTENT BY PHOTOMETRIC METHODS"

(brought into force by order of the Federal Agency for Technical Regulation and Metrology of November 11, 2014 N 1539-st)

Drinking water. Determination of manganese content by photometric methods

Instead of GOST 4974-72

Foreword

The goals, basic principles and procedure for carrying out work on interstate standardization are established by GOST 1.0-92 "Interstate standardization system. Basic provisions" and GOST 1.2-2009 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for development, adoption, application , updates and cancellations "

Information about the standard

1 Prepared by the Protector Limited Liability Company in conjunction with the Lumex Marketing Limited Liability Company

2 Submitted by the Federal Agency for Technical Regulation and Metrology, Technical Committee for Standardization TC 343 "Water Quality"

3 Adopted by the Interstate Council for Standardization, Metrology and Certification (minutes of October 20, 2014 N 71-P)

4 This standard has been developed taking into account the basic regulations of the international standard ISO 6333: 1986 Water quality - Determination of manganese - Formaldoxime spectrometric method, in part of clause 7

Degree of Compliance - Non-Equivalent (NEQ)

5 Replaces GOST 4974-72

6 By order of the Federal Agency for Technical Regulation and Metrology of November 11, 2014 N 1539-st, the interstate standard GOST 4974-2014 was put into effect as a national standard of the Russian Federation from January 1, 2016.

1 area of use

This standard applies to drinking water, including packaged in containers, and water from underground and surface sources of drinking water supply and establishes photometric methods for determining the content of manganese in the range of mass concentrations from 0.01 to 5.00 mg / dm 3 using:

Oxidation of manganese compounds to permanganate ions after removing the interfering effect of chloride ions (method A);

Formation of a colored compound with formaldoxime (method B).

If the mass concentration of manganese exceeds 5 mg / dm 3, then the analyzed sample is diluted with distilled water, but not more than 100 times.

The methods provide comparable results.

2 Normative references

This standard uses normative references to the following interstate standards:

GOST OIML R 76-1-2011 State system for ensuring the uniformity of measurements. Scales of non-automatic operation. Part 1. Metrological and technical requirements. Testing

GOST 17.1.5.05-85 Nature protection. Hydrosphere. General requirements for sampling surface and sea waters, ice and atmospheric precipitation

GOST 195-77 Reagents. Sodium sulfate. Technical conditions

GOST 1277-75 Reagents. Silver nitrate. Technical conditions

GOST 1625-89 Technical formalin. Technical conditions

GOST 1770-74 (ISO 1042-83, ISO 4788-80) Laboratory glassware. Cylinders, beakers, flasks, test tubes. General specifications

GOST 3760-79 Reagents. Ammonia water. Technical conditions

GOST 4146-74 Reagents. Potassium persulphate. Technical conditions

GOST 4204-77 Reagents. Sulfuric acid. Technical conditions

GOST 4208-72 Reagents. Salt of ferrous oxide and ammonium double sulfate (Mohr's salt). Technical conditions

GOST 4328-77 Reagents. Sodium hydroxide. Technical conditions

GOST 4461-77 Reagents. Nitric acid. Technical conditions

GOST 4523-77 Reagents. Magnesium sulfate 7-water. Technical conditions

GOST 4919.1-77 Reagents and highly pure substances. Methods for preparing indicator solutions

GOST 5456-79 Reagents. Hydroxylamine hydrochloride. Technical conditions

GOST ISO 5725-6-2003 Accuracy (correctness and precision) of measurement methods and results. Part 6. Using precision values in practice

GOST 6552-80 Reagents. Orthophosphoric acid. Technical conditions

GOST 6709-72 Distilled water. Technical conditions

GOST 9147-80 Porcelain laboratory ware and equipment. Technical conditions

GOST 10652-73 Reagents. Disodium ethylenediamine-N, N, N ", N" -tetraacetic acid 2-aqueous salt (Trilon B). Technical conditions

GOST 10733-98 Wrist watches and mechanical pocket watches. General specifications

GOST 10929-76 Reagents. Hydrogen peroxide. Technical conditions

GOST 14919-83 Household electric stoves, hotplates and electric ovens. General specifications

GOST ISO IEC 17025-2009 General requirements for the competence of testing and calibration laboratories

GOST 19908-90 Crucibles, bowls, glasses, flasks, funnels, test tubes and tips made of transparent quartz glass. General specifications

GOST 20478-75 Reagents. Ammonium persulphate. Technical conditions

GOST 23350-98 Wrist and pocket electronic watches. General specifications

GOST 24147-80 High purity water ammonia. Technical conditions

GOST 25336-82 Laboratory glassware and equipment. Types, main parameters and dimensions

GOST 26272-98 Electronic-mechanical quartz wrist and pocket watches. General specifications

GOST 29227-91 (ISO 835-1-81) Laboratory glassware. Graduated pipettes. Part 1. General requirements

GOST 31861-2012 Water. General requirements for sampling

GOST 31862-2012 Drinking water. Sample selection*

Note - When using this standard, it is advisable to check the operation of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current year, and by the issues of the monthly information index "National Standards" for the current year. If the reference standard is replaced (changed), then when using this standard, the replacing (modified) standard should be followed. If the reference standard is canceled without replacement, then the provision in which the reference to it is given applies to the extent not affecting this reference.

3 Sampling

3.1 Water samples are taken in accordance with GOST 31861, GOST 31862 and GOST 17.1.5.05 with a volume of at least 1000 cm 3 in containers made of glass or polymer material.

3.2 If the determination of manganese by method A is supposed to be carried out not earlier than 12 hours after sampling, then the selected sample is preserved by adding concentrated nitric acid at the rate of 5 cm 3 of acid per 1000 cm 3 of the sample. If the pH of the preserved sample is higher than 2, then add nitric acid until the pH reaches less than 2 (control by universal indicator paper).

3.3 When using method B, the sample is preserved by adding 10 cm 3 of a sulfuric acid solution according to 7.3.6. If the pH of the preserved sample is higher than 2, then add a solution of sulfuric acid until the pH is less than 2 (control by universal indicator paper).

3.4 The shelf life of a sample preserved according to 3.2 or 3.3 is no more than 1 month. at a temperature from 2 ° C to 8 ° C.

4 Requirements for measurement conditions

4.1 When preparing for measurements and during their conduct, it is necessary to comply with the conditions established in the operating manuals or in the passports of measuring instruments and auxiliary equipment.

4.2 Measurements of volumes of water and solutions are carried out at an ambient temperature of 15 ° C to 25 ° C.

4.3 All solutions, unless otherwise specified, should be stored at an ambient temperature of 15 ° C to 25 ° C in closed containers.

4.4 Laboratories conducting tests must comply with the requirements of GOST ISO / IEC 17025.

INTERSTATE COUNCIL FOR STANDARDIZATION. METROLOGY AND CERTIFICATIONS

INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

DRINKING WATER

Determination of manganese content by photometric methods

(ISO 6333: 1986, NEQ)

Official edition

Standardinform

Foreword

The goals, basic principles and procedure for carrying out work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic Provisions "and GOST 1.2-2009" Interstate Standardization System. Interstate standards, rules and recommendations for interstate standardization. Rules for development, acceptance, application, updating and cancellation "

Information about the standard

1 PREPARED by Limited Liability Company "Protector" together with Limited Liability Company "Lumex Marketing"

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology. Technical Committee for Standardization TC 343 "Water Quality"

3 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification (minutes of October 20, 2014 N? 71-P)

4 This standard has been developed taking into account the main provisions of the international standard ISO 6333: 1986 Water quality - Determination of manganese - Formaldoxime spectrometric method, in part of clause 7

Degree of Compliance - Non-Equivalent (NEQ)

6 By order of the Federal Agency for Technical Regulation and Metrology of November 11, 2014 No. 1539-st, the interstate standard GOST 4974-2014 was put into effect as a national standard of the Russian Federation from January 1, 2016.

10% solution of magnesium sulfate (6.3.1.2). mix again and leave until sediment of magnesium hydroxide, with which manganese is coprecipitated, to the bottom of the glass. Depending on the expected value of the mass concentration of manganese, the volume of the aliquot can be increased to 500 cm 3. In this case, the volume of the added solutions of sodium hydroxide and magnesium sulfate is changed proportionally.

If the water sample was preserved during sampling, then the volume of sodium hydroxide solution determined in accordance with 6.3.1.11.1 is added to the sample aliquot and then all the operations provided for the unconserved sample are carried out, starting with the addition of magnesium sulfate solution.

6.3.1.11.3 After settling, most of the solution is decanted over the precipitate, and the residue is filtered through an ash-free "red ribbon" filter. The filter cake is washed two to three times with distilled water and dissolved in 10 cm 3 of orthophosphoric acid solution (6.3.1.3), collecting the filtrate in a volumetric flask with a capacity of V 2 = 50 cm 3.

Wash the filter with distilled water two to three times like this. so that the total volume of the filtrate and wash water in the flask is approximately 35 cm 3. Then add 10 cm 3 of 1% silver nitrate solution (6.3.1.5) and mix. In this case, there should be no clouding of the solution due to the formation of silver chloride. About 0.3 g of ammonium persulfate or potassium persulfate is added to the solution, brought to a boil on a hotplate and kept in a boiling water bath for 10 minutes.

After cooling, the solution is brought to the mark with distilled water and the optical density is measured according to 6.3.2.

6.3.1.11.4 If, after adding the silver nitrate solution (6.3.1.5), a white precipitate or cloudiness forms, shake the flask containing the solution until then. until the precipitate gathers into lumps and the solution clears. Then the solution is centrifuged or filtered through a dry "red tape" filter into another volumetric flask with a capacity of 50 cm 3, the precipitate is washed 2-3 times with a small amount of distilled water and discarded. 0.3 g of ammonium persulfate or potassium persulfate (Section 5) is added to the filtrate with wash water. bring to a boil on a hotplate and incubate in a boiling water bath for 10 minutes. After cooling, the solution is brought to the mark with distilled water and the optical density is measured according to 6.3.2.

6.3.1.11.5 Prepare a blank sample in the same way, replacing the sample of the analyzed water with distilled water. If the water sample has been preserved (see 3.2), then before the analysis of the blank sample, add nitric acid to it in the same volume as when preserving the water sample.

6.3.2 Conduct of measurements

Measure the optical density of the sample and the blank sample prepared in accordance with 6.3.1.11 with respect to distilled water at least three times under the same conditions in which the calibration solutions were measured (see 6.3.1.8).

Calculate the arithmetic mean of the values obtained.

If the value of the optical density of the prepared sample is outside the upper limit of the range of the calibration characteristic, then the analysis of the sample is repeated by taking a smaller aliquot, or the water sample is diluted with distilled water before the start of the analysis and all operations are carried out with the diluted sample according to 6.3.1.11.1 6.3.1.11.4 ...

Dilution factor (calculated by the formula

where V is the volume of the volumetric flask used to dilute the sample, cm 3;

The volume of the sample aliquot taken for dilution, cm 3.

6.3.3 Processing of measurement results

6.3.3.1 If there is a computer (microprocessor) system for collecting and processing information, the procedure for processing the results is determined by the manual (instruction) for the operation of the device.

6.3.3.2 In the absence of a computer (microprocessor) system for collecting and processing information, the mass concentration of manganese in a water sample X. mg / dm 3 is calculated by the formula

Information about changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments is published in the monthly information index "National Standards". In the event of a resehot (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notice and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

In the Russian Federation, this standard cannot be reproduced in whole or in part. replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology

1 area of use............................................... .................................................. ....................................one

3 Sampling ............................................... .................................................. .................................................. ..2

4 Requirements for the conditions of measurements ............................................ ............................................ 2

5 Measuring instruments, auxiliary equipment, reagents, materials ...................................... 3

6 Determination of manganese content using oxidation to permanganate ions

(method A) .............................................. .................................................. .................................................. ......4

7 Determination of manganese content using formaldoxime (method B) .......................... 11

Bibliography................................................. .................................................. ..............................................15

INTERSTATE STANDARD

DRINKING WATER Determination of manganese content by photometric methods Drinking water. Determination ot manganese content by photometric methods

Date of introduction - 2016-01-01

1 area of use

This standard applies to drinking water, including packaged in containers. and water from underground and surface sources of drinking water supply and establishes photometric methods for determining the content of manganese in the range of mass concentrations from 0.01 to 5.00 mg / dm 3 using:

Oxidation of manganese compounds to permanganate ions after removing the interfering effect of chloride ions (method A);

Formation of a colored compound with formaldoxime (method B).

If the mass concentration of manganese exceeds 5 mg / dm 3. then the analyzed sample is diluted with distilled water, but not more than 100 times.

The methods provide comparable results.

This standard uses normative references to the following interstate standards:

GOST OIML R 76-1-2011 State system for ensuring the uniformity of measurements. Scales of non-automatic operation. Part 1. Metrological and technical requirements. Testing

4.2 Measurements of volumes of water and solutions are carried out at an ambient temperature of 15 ° C to 25 ° C.

4.3 All solutions, unless otherwise specified, should be stored at an ambient temperature of 15 ° C to 25 “C in closed containers.

4.4 Laboratories conducting tests must comply with the requirements of GOST ISO / IEC 17025.

5 Measuring instruments, auxiliary equipment, reagents, materials

Photometer, spectrophotometer, photoelectrocolorimeter, photometric analyzer (hereinafter referred to as the device), allowing to measure the optical density of a solution in the wavelength range from 400 to 700 nm with an admissible absolute measurement error of the spectral transmittance of no more than ± 2% in optical cells with a thickness of the light-absorbing layer from 1 to 10 cm.

Interstate standard sample of the composition of aqueous solutions of manganese (II) ions with a mass concentration of 1 g / dm 3 with a permissible relative error of the certified value of no more than ± 2% at a confidence level of P = 0.95.

Scales of non-automatic operation in accordance with GOST OIML R 76-1 with limits of permissible absolute error no more than ± 0.001 g.

Volumetric flasks 2-50-2. 2-100-2, 2-200-2. 2-1000-2 in accordance with GOST 1770.

Measuring cylinders 2-10-2, 2-25-2. 2-50-2. 2-100-2. 2-200-2, 2-500-2, 2-1000-2 in accordance with GOST 1770.

Pipettes, graduated 1-1-2-1, 1-1-2-2. 1-1-2-5. 1-1-2-10 or other types and designs in accordance with GOST 29227.

Household electric stove in accordance with GOST 14919.

Water bath of any type.

Mechanical or electronic stopwatch or mechanical clock according to GOST 10733. or electronic clock according to GOST 23350. or electronic-mechanical quartz clock according to GOST 26272 of any brand or timer.

Centrifuge of any type, suitable for centrifugation of liquid volumes up to 100 cm 3 and providing a rotation speed of at least 85 s "(5000 rpm)

Household refrigerator of any type, providing a temperature from 2 ° C to 8 J C.

Conical heat-resistant flasks with a capacity of 50.100.250.500.1000. 1500 cm 3 in accordance with GOST 25336.

Chemical glasses with a capacity of 1000 cm 3 in accordance with GOST 25336.

Evaporation bowls are porcelain GOST 9147 or quartz bowls in accordance with GOST 19908.

Glass sticks

Ash-free filters "red tape"

Ammonium persulphate (persulfate) in accordance with GOST 20478. analytical grade.

Magnesium sulfate 7-water in accordance with GOST 4523. x. h. or h. d. a.

Sodium hydroxide (sodium hydroxide) in accordance with GOST 4328. х. h. or h. d. a.

Orthophosphoric acid in accordance with GOST 6552, x. h. or h. d. a.

Nitric acid in accordance with GOST 4461, x. h. or h. d. a.

Sulfuric acid in accordance with GOST 4204, analytical grade.

Silver nitrate according to GOST 1277, analytical grade

Mercury sulfate oxide. p.a., mass fraction of the main substance not less than 98%

Distilled water in accordance with GOST 6709.

Potassium persulfate (persulfate) according to GOST 4146 or sodium persulfate (persulfate), analytical grade a.

Sodium sulfate (sodium sulfate) in accordance with GOST 195. anhydrous, analytical grade.

Sodium sulfite in accordance with GOST 195, anhydrous, analytical grade.

Hydrogen peroxide in accordance with GOST 10929. x. h. or h. d. a.

Disodium salt ethylenediamine-MM.1CH \ N "-tetrauceenic acid 2-aqueous (Trilon B) according to GOST 10652.

Note - It is allowed to use tetrahydrate (CioHuN; Na «Oj-4H; 0) or dihydrate (CtoHijl4.-NaiOa-2HiO) tetrasodium salt of ethylenediaminetetrasucetic acid.

Hydroxylamine hydrochloride according to GOST 5456.

Formaldehyde (YASNO), aqueous solution (formalin) according to GOST 1625.

Ammonia water in accordance with GOST 3760. chemically pure. or according to GOST 24147, special ch.

Salt of ferrous oxide and ammonium double sulfate (Mohr's salt) in accordance with GOST 4208.

Phenolphthalein (indicator), alcohol solution with a mass fraction of 0.1% according to GOST 4919.1.

Universal indicator paper.

Note - It is allowed to use other measuring instruments, apparatus, auxiliary devices and materials with metrological and technical characteristics not worse than those specified in this standard, as well as chemical reagents of a higher qualification.

6 Determination of manganese content using oxidation to permanganate ions (method A)

6.1 The essence of the method

The essence of the method lies in the catalytic oxidation of manganese compounds with potassium persulfate or sodium persulfate to permanganate ions, followed by measuring the optical density of the solution and calculating the mass concentration of manganese in the water sample. When using an instrument equipped with a monochromator, set the operating wavelength to 525 nm. when using filter devices, choose a filter that has an absorption maximum in the region of (530 ± 20) nm.

Depending on the method for eliminating the interfering effect of chloride ions, the following method options are established:

1 using magnesium hydroxide coprecipitation;

2 with evaporation with sulfuric acid:

3 - using complexation with mercury (II).

6.2 Disturbing influences

Interfering influences are eliminated during sample preparation. Elimination of interfering influences in variant 3 is effective if the content of chloride ions in an aliquot of a sample taken for analysis does not exceed 0.1 g.

6.3 Determination of manganese content with elimination of the interfering effect of chloride ions

coprecipitation with magnesium hydroxide (option 1)

6.3.1 Preparing for measurements

6.3.1.1 Preparation of a stock solution of manganese with a mass concentration of 10 mg / dm 1

In a volumetric flask with a capacity of 100 cm, 1 cm of a standard sample of a solution of manganese (II) ions with a mass concentration of 1 g / dm 3 is pipetted, diluted with distilled water to about half of the volume of the flask, add 0.5 cm 3 of concentrated nitric acid and bring to the mark with distilled water ...

The shelf life of the solution is no more than 1 month.

6.3.1.2 Preparation of a 10% solution of magnesium sulfate

In a conical flask (or glass) with a capacity of 100 ml, 10 g of 7-aqueous magnesium sulfate is introduced and dissolved in 90 cm 3 of distilled water.

The shelf life of the solution is no more than 6 months.

6.3.1.3 Preparation of a 20% volume fraction of phosphoric acid solution

800 cm 3 of distilled water is placed in a glass with a capacity of 1000 cm 3 and 200 cm 3 of orthophosphoric acid is added carefully with stirring and, if necessary, with external cooling.

The shelf life of the solution is no more than 1 year.

6.3.1.4 Preparation of 4% sodium hydroxide solution

In a conical flask with a capacity of 100 cm 3 place 96 cm 3 of distilled water and add 4 g of sodium hydroxide After dissolving sodium hydroxide, the solution is transferred into a vessel made of polymeric material.

The shelf life of the solution is no more than 2 months.

6.3.1.5 Preparation of 1% silver nitrate solution

In a volumetric flask with a capacity of 100 cm 'add 1 g of silver nitrate, dissolve in distilled water and then bring to the mark with distilled water.

The shelf life of the solution in a dark glass container is no more than 1 month.

6.3.1.6 Preparation of calibration solutions

In conical heat-resistant flasks with a capacity of 50 or 100 cm 1 add with a pipette 0.00; 0.25; 0.50; 1.00; 2.00; 3.00; 4.00; 5.00 cm 3 stock solution of manganese (6.3.1.1). Add to each flask 10 cm 3 of a 20% volume fraction of phosphoric acid solution (see 6.3.1.3), 10 cm 3 of silver nitrate solution (see 6.3.1.5) and 0.3 g of potassium persulfate or sodium persulfate. The contents of the flasks are diluted with distilled water to about 40 cm 3, brought to a boil on a hotplate and boiled for 3 minutes.

The solutions are cooled in a stream of cold water, transferred to volumetric flasks with a capacity of 50 cm 3, brought to the mark with distilled water and mixed. The mass concentration of manganese in the prepared calibration solutions is equal to 0.00, respectively; 0.05; 0.10; 0.20; 0.40; 0.60; 0.80; 1.00 mg / dm 3.

The manganese-free calibration solution is a blank for calibration.

Calibration solutions are prepared on the day of use.

6.3.1.7 Preparing the device

The preparation of the device for operation is carried out in accordance with the manual (instruction) for the operation of the device.

6.3.1.8 Instrument calibration

Measure the absorbance of all calibration solutions and the calibration blank (6.3.1.6) three times at the wavelength specified in 6.1. in an optical cell with a thickness of the light-absorbing layer from 2 to 4 cm. using distilled water as a reference solution.

For each calibration solution, the arithmetic mean value is calculated from the obtained optical density values.

The calibration characteristic is set in the form of the dependence of the arithmetic mean values of the optical density of the calibration solutions minus the arithmetic mean of the optical density of the blank sample from the mass concentration of manganese in the corresponding solution. Wherein;

If the device is equipped with a computer (microprocessor) system for collecting and processing information. then the calibration characteristic is set in accordance with the manual (instruction) for the operation of the device;

If the device does not provide for automated calibration, then the obtained calibration characteristics are processed by the linear regression method using the software intended for this purpose. In the absence of such a possibility, the slope of the calibration characteristic b is calculated. (optical density units) dm 3 mg ". according to the formula

where the mass concentration of manganese in the th calibration solution, mg / dm 3;

A, is the arithmetic mean of the optical density of the i-th calibration solution minus the optical density of the blank sample for calibration, the unit of optical density;

I is the number of calibration solutions.

Note - The software for some devices allows you to calculate the calibration coefficient K, equal to 1 / b.

6.3.1.9 Verification of the acceptability of the calibration characteristic

The verification of the acceptability of the calibration characteristic using a computer (microprocessor) system for collecting and processing information is carried out in accordance with the manual (instruction) for the operation of the device.

If the device does not have software that provides for automated calibration, then for each calibration solution, calculate the value of the slope of the calibration characteristic Lc (optical density unit) dm 3 mg according to the formula

where A, and Cr see 6.3.1.8.

The calibration characteristic is recognized as acceptable when the conditions are met at each calibration point

where b is the value of the slope of the calibration characteristic, calculated by the formula (1), (units of optical density) dm 3 mg 1.

If this condition is not met, then the establishment of the calibration characteristic is repeated.

6.3.1.10 Control of the stability of the calibration characteristic

The stability of the calibration characteristic is monitored at least once a quarter, as well as when replacing reagents, after repair or a long downtime of the device. For control, use one or two newly prepared calibration solutions according to 6.3.1.6 (hereinafter referred to as control solutions).

Measure the optical density of the control solutions in the same way as in 6.3.1.8 and, using the calibration characteristic, from the obtained optical density values, calculate the value of the mass concentration of manganese in the control solutions.

The calibration characteristic is considered stable when the condition

1 C - C, 1 10.12, (4)

where C „iM” is the mass concentration of manganese in the calibration solution obtained with the control

measurement, mg / dm 3;

С „- the actual value of the mass concentration of manganese in the calibration solution. mg / dm 3.

If condition (4) is not met for only one control solution, then this control solution is prepared again and repeated measurements are made. The results of the repeated control are considered final. In this case, if the condition of stability of the calibration characteristic is not met. then the instrument is calibrated again.

6.3.1.11 Preparing water samples for analysis

6.3.1.11.1 If the water sample has been preserved (3.2), then determine the volume of 4% sodium hydroxide solution required to neutralize the acid.

To do this, take an aliquot of water with a volume of V \ = 100 cm 3, add 3 to 5 drops of a 1% alcohol solution of phenolphthalein and pour from a graduated pipette a 4% sodium hydroxide solution (6.3.1.4) until it does not disappear for 30 s pink in color. Record the volume of the sodium hydroxide solution consumed and, if necessary, recalculate it by the volume of the aliquot of the sample taken for the determination according to 6.3.1.11.2. Discard the aliquot used to find the volume of the sodium hydroxide solution.

6.3.1.11.2 If the water sample was not preserved during sampling, add 2 ml of a 4% sodium hydroxide solution (6.3.1.4) to a 100 ml aliquot J of the sample. mix, add 2 cm "

INTERSTATE COUNCIL FOR STANDARDIZATION. METROLOGY AND CERTIFICATIONS

INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

DRINKING WATER

Determination of manganese content by photometric methods

(ISO 6333: 1986, NEO)

Official edition

Stagesartyforms

Foreword

The goals, basic principles and procedure for carrying out work on interstate standardization are established by GOST 1.0-92 and the Interstate Standardization System. Basic provisions) "and GOST 1.2-2009" Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for development, acceptance, application, updating and cancellation "

Information about the standard

1 PREPARED by Limited Liability Company "Protector" together with Limited Liability Company "Lumex Marketing"

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology. Technical Committee for Standardization TC 343 "Water Quality"

3 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification (minutes of October 20, 2014 No. 71 -P)

4 This standard has been developed taking into account the main provisions of the international standard ISO 6333: 1986 Water quality - Determination of manganese - Fonmaldoxime spectrometric method. in part of section 7

Compliance Degree - Non-Equivalent (NEO)

5 REPLACE GOST 4974-72

Information about changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information. notice and texts are also posted on the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

1 area of use............................................... .................................................. ....................................one

3 Sampling ............................................... .................................................. ..................................

4 Requirements for the conditions of measurements ............................................ ..........................

5 Measuring instruments, auxiliary equipment, reagents, materials ....................

6 Determination of manganese content using oxidation to permanganate ions

INTERSTATE STANDARD

DRINKING WATER

Determination of manganese content by photometric methods Drinking water. Determination ot manganese content by photometric methods

Date of introduction - 2016-01-01

1 area of use

* oxidation of manganese compounds to permanganate ions after elimination of the interfering effect of chloride ions (method A):

Formation of a colored compound with formaldoxime (method B).

If the mass concentration of manganese exceeds 5 mg / dm 3. then the analyzed sample is diluted with distilled water, but not more than 100 times.

The methods provide comparable results.

This standard uses normative references to the following interstate standards:

GOST OIML R 76-1-2011 State system for ensuring the uniformity of measurements. Scales of non-automatic operation. Part 1. Metrological and technical requirements. Testing

GOST 17.1.5.05-65 Nature Protection. Hydrosphere. General requirements for sampling of surface and sea waters. ice and precipitation

GOST 195-77 Reagents. Sodium sulfate. Specifications GOST 1277-75 Reagents. Silver nitrate. Specifications GOST 1625-89 Technical formalin. Technical conditions

GOST 1776-74 (ISO 1042-63, ISO 4788-60) Laboratory glassware. Cylinders. beakers, flasks, test tubes. General specifications

GOST 3760-79 Reagents. Ammonia water. Specifications GOST 4146-74 Reagents. Potassium perhydrate. Specifications GOST 4204 - 77 Reagents. Sulfuric acid. Technical conditions

GOST 4208-72 Reagents. Salt of ferrous oxide and ammonium double sulfate (Mohr's salt). Technical conditions

GOST 4328-77 Reagents. Sodium hydroxide. Specifications GOST 4461-77 Reagents. Nitric acid. Specifications GOST 4523 -77 Reagents. Magnesium sulfate 7-water. Specifications GOST 4919.1-77 Reagents and highly pure substances. Methods for preparing indicator solutions

GOST 5456-79 Reagents. Hydroxylamine hydrochloride. Technical conditions

Official edition

GOST ISO 5725-6-2003 Accuracy (correctness and precision) of measurement methods and results. Part 6. Using precision values in practice

GOST 6552-80 Reagents. Orthophosphorium acid. Specifications GOST 6709-72 Distilled water. Technical conditions

GOST 9147 * 80 Porcelain laboratory glassware and equipment. Specifications GOST 10652-73 Reagents. Disodium salt ethylenediamine-MXN ".M'-tetraacetic acid 2-aqueous (Trilon B). Specifications

GOST 10733 * 98 Mechanical wrist and pocket watches. General specifications GOST 10929 * 76 Reagents. Hydrogen peroxide. Technical conditions

GOST 14919-83 Household electric stoves, hotplates and electric ovens. General specifications

GOST ISO IEC 17025-2009 General requirements for the competence of testing and calibration laboratories

GOST 19908 * 90 Crucibles, bowls, glasses, flasks, funnels, test tubes and tips made of transparent quartz glass. General specifications

GOST 20478-75 Reagents. Ammonium persulphate. Technical conditions

GOST 23350 * 98 Wrist watches and electronic pocket watches. General specifications

GOST 24147-80 High purity water ammonia. Technical conditions

GOST 25336-82 Laboratory glassware and equipment. Types, main parameters and dimensions

GOST 26272 * 98 Electronic * mechanical quartz wrist and pocket watches. General specifications

GOST 29227-91 (ISO 835-1-61) Laboratory glassware. Graduated pipettes. Part 1. General requirements

GOST 31861-2012 Water. General requirements for sampling GOST 31862-2012 Drinking water. Sample selection"

Note - When using this standard, it is advisable to check the validity of the reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrolopes on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current pod. and on the issues of the monthly information index "National Standards" for the current year. If the reference "1st standard is replaced (changed), then when using this standard, one should be guided by the replacing (modified) standard. If the reference standard is canceled without replacement, then the provision in which the reference to it is given applies to the extent not affecting this reference.

3 Sampling

3.1 Water samples are taken in accordance with GOST 31861. GOST 31862 and GOST 17.1.5.05 with a volume of at least 1000 cm 3 in containers made of glass or polymer material.

3.2 If the determination of manganese by method A is supposed to be carried out not earlier than 12 hours after sampling, then the selected sample is preserved by adding concentrated nitric acid at the rate of 5 cm 3 of acid per 1000 cm 3 of the sample. If the pH of the preserved sample is higher than 2., add nitric acid until the pH reaches less than 2 (control using universal indicator paper).

3.3 When using method B, the sample is preserved by adding 10 cm 3 of a sulfuric acid solution according to 7.3.6. If the pH of the preserved sample is higher than 2, then add a solution of sulfuric acid until the pH reaches less than 2 (control by universal indicator paper).

3.4 The shelf life of a sample preserved according to 3.2 or 3.3 is no more than 1 month. at a temperature from 2 ° C to 8 ° C.

4 Requirements for measurement conditions

The Russian Federation has GOST R 56237 * 2014 (ISO 5667-6: 2006)

4.2 Measurements of the volumes of water and solutions are carried out at an ambient temperature of 15 ° C to 25 ° C.

4.3 All solutions, unless otherwise specified, should be stored at an ambient temperature of 15 ° C to 25 ° C in closed containers.

4.4 Laboratories conducting tests must comply with the requirements of GOST ISO / IEC 17025.

5 Measuring instruments, auxiliary equipment, reagents, materials

Scales of non-automatic operation in accordance with GOST OIML R 76-1 with limits of permissible absolute error no more than ± 0.001 g.

Volumetric flasks 2-50-2,2-100-2, 2-200-2.2-1000-2 in accordance with GOST 1770.

Measuring cylinders 2-10-2, 2-25-2, 2-50-2.2-100-2. 2-200-2.2-500-2, 2-1000-2 in accordance with GOST 1770.

Pipettes, graduated 1-1 -2-1, 1-1 -2-2. 1-1 -2-5. 1-1-2-10 or other types and designs in accordance with GOST 29227.

Household electric stove in accordance with GOST 14919.

Water bath of any type.

Mechanical or electronic stopwatch or mechanical clock according to GOST 10733, or electronic clock according to GOST 23350. or electronic-mechanical quartz clock according to GOST 26272 of any brand or timer.

A centrifuge of any type, suitable for centrifuging liquid volumes up to 100 cm3 and providing a rotation speed of at least 85 s "(5000 obUminugu)

Household refrigerator of any type, providing temperature from 2 ° С to 8 ° С.

Conical heat-resistant flasks with a capacity of 50.100, 250.500.1000.1500 cm 3 in accordance with GOST 25336.

Chemical glasses with a capacity of 1000 cm 3 in accordance with GOST 25336.

Evaporation bowls are porcelain GOST 9147 or quartz bowls in accordance with GOST 19908.

Glass sticks

Ash-free filters and red tape "

Ammonium persulphate (persulfate) in accordance with GOST 20478. analytical grade.

Magnesium sulfate 7-aodic according to GOST 4523. x. h. or h. d. a.

Sodium hydroxide (sodium hydroxide) in accordance with GOST 4328. х. h. or h. d. a.

Orthophosphoric acid in accordance with GOST 6552. х. h. or h. d. a.

Nitric acid in accordance with GOST 4461. х. h. or h. d. a.

Sulfuric acid in accordance with GOST 4204, analytical grade.

Silver nitrate according to GOST 1277, analytical grade

Mercury sulfate oxide. p.a., mass fraction of the main substance not less than 98%

Distilled water in accordance with GOST 6709.

Potassium persulfate (persulfate) according to GOST 4146 or sodium persulfate (persulfate), analytical grade

Sodium sulfate (sodium sulfate) in accordance with GOST 195. anhydrous, analytical grade.

Sodium sulfite in accordance with GOST 195. anhydrous, analytical grade.

Hydrogen peroxide in accordance with GOST 10929. x. h. or h. d. a.

Disodium ethylenediamium salt-MMNo.No "Tetraacetic acid 2-aqueous (Trilon B) according to GOST 10652.

Note - It is allowed to use tetrahydrate (C.oHuNiNa ^^ H.-O) or dihydrate (CioHwl4 / Na «Oo * 2H-0) of tetra sodium salt of ethylenediaminetraacetic acid.

Hydroxylamine hydrochloride according to GOST 5456.

Formaldehyde (НСНО), aqueous solution (formalin) according to GOST 1625.

Ammonia water in accordance with GOST 3760. chemically pure. or according to GOST 24147, special ch.

Salt of ferrous oxide and ammonium double sulfate (Mohr's salt) in accordance with GOST 4208.

Phenolphthalein (indicator), alcohol solution with a mass fraction of 0.1% according to GOST 4919.1.

Universal indicator paper.

6 Determination of manganese content using oxidation to permanganate ions (method A)

6.1 The essence of the method

The essence of the method lies in the catalytic oxidation of manganese compounds with potassium persulfate or sodium persulfate to permanganate ions, followed by measuring the optical density of the solution and calculating the mass concentration of manganese in the water sample. When using an instrument equipped with a monochromator, set the operating wavelength to 525 nm. when using filter devices, select a filter that has an absorption maximum in the region of (530 ± 20) nm.

Depending on the method for eliminating the interfering effect of chloride ions, the following method options are established:

1 using magnesium hydroxide coprecipitation:

2 with evaporation with sulfuric acid:

3 using complexation with mercury (II).

6.2 Interfering influences

6.3 Determination of manganese content with elimination of the interfering effect of chloride ions

coprecipitation with magnesium hydroxide (option 1)

6.3.1 Preparing for measurements

6.3.1.1 Preparation of a stock solution of manganese with a mass concentration of 10 mg / dm e

In a volumetric flask with a capacity of 100 cm 3, pipette 1 cm 3 of a standard sample of the composition of a solution of manganese (II) ions with a mass concentration of 1 g / dm 3, dilute with distilled water to about half the volume of the flask, add 0.5 cm3 of concentrated nitric acid and bring to the mark with distilled water.

6.3.1.2 Preparation of a 10% solution of magnesium sulfate

In a conical flask (or glass) with a capacity of 100 cm 3, add 10 g of 7-aqueous magnesium sulfate and dissolve in 90 cm 3 of distilled water.

The shelf life of the solution is not more than 6 months.

6.3.1.3 Preparation of a 20% volume fraction of phosphoric acid solution

800 cm 3 of distilled water is placed in a glass with a capacity of 1000 cm 3 and 200 cm 3 of e orthophosphoric acid is added carefully with stirring and, if necessary, with external cooling.

6.3.1.4 Preparation of 4% sodium hydroxide solution

In a conical flask with a capacity of 100 cm 3 place 96 cm 3 of distilled water and add 4 g of sodium hydroxide. After dissolving sodium hydroxide, the solution is transferred to a vessel made of polymeric material.

The shelf life of the solution is no more than 2 months.

6.3.1.5 Preparation of 1% silver nitrate solution

1 g of silver nitrate is introduced into a volumetric flask with a capacity of 100 cm 3, dissolved in distilled water and then brought to the mark with distilled water.

6.3.1.6 Preparation of calibration solutions

In conical heat-resistant flasks with a capacity of 50 or 100 ml oe add 0.00: 0.25 with a pipette; 0.50; 1.00; 2.00; 3.00: 4.00; 5.00 cm 3 stock solution of manganese (6.3.1.1). Add to each flask 10 ml of phosphoric acid solution 20% by volume (see 6.3.1.3). 10 cm 3 of silver nitrate solution (see 6.3.1.5) and 0.3 g of potassium persulfate or sodium persulfate. The contents of the flasks are diluted with distilled water to about 40 cm 3, brought to a boil on a hotplate and boiled for 3 minutes.

The solutions are cooled in a stream of cold water, transferred to volumetric flasks with a capacity of 50 ml oe. bring to the mark with distilled water and mix. The mass concentration of manganese in the prepared calibration solutions is equal to 0.00, respectively; 0.05; 0.10; 0.20; 0.40; 0.60; 0.80; 1.00 mg / dm 3.

The manganese-free calibration solution is a blank for calibration.

6.3.1.7 Preparing the device

6.3.1.8 G instrument radiometer

For each calibration solution, the arithmetic mean value is calculated from the obtained optical density values.

1 (C,) 2

where C is the mass concentration of manganese in the w calibration solution, mg / dm 3;

A is the arithmetic mean of the optical density of the / th calibration solution minus the optical density of the blank sample for calibration, optical density units:

I is the number of calibration solutions.

Note - The software for some devices allows you to calculate the calibration coefficient K, equal to 1 / b.

6.3.1.9 Verification of the acceptability of the calibration characteristic

If the device does not have software providing for automated calibration, then for each calibration solution, calculate the value of the slope of the calibration characteristic L * (optical density units) dm 3 mg ". According to the formula

where A and C, - see 6.3.1.8.

The calibration characteristic is recognized as acceptable when the conditions are met at each calibration point

! ^ - 4s0.10. (3)

where 6 is the value of the slope of the calibration characteristic, calculated by the formula (1). (optical density units) dm 3 * mg ".

If this condition is not met, then the establishment of the calibration characteristic is repeated.

6.3.1.10 Control of the stability of the calibration characteristic

Measure the absorbance of the control solutions in the same way as in 6.3.1.8 and. using the calibration characteristic, on the obtained values of the optical density, the value of the mass concentration of manganese in the control solutions is calculated.

The calibration characteristic is considered stable when the condition

I 0 - "- ~ C" I $ 0.12. (4)

where C meas is the mass concentration of manganese in the calibration solution obtained with the control

measurement. mg / dm 3;

C i is the actual value of the mass concentration of manganese in the calibration solution. mg / dm 3.

6.3.1.11 Preparing water samples for analysis

6.3.1.11.1 If the water sample has been preserved (3.2), then determine the volume of 4% sodium hydroxide solution required to neutralize the acid.

To do this, take an aliquot of water with a volume of Vi = 100 cm 3, add 3 to 5 drops of a 1% alcohol solution of phenolphthalein and pour in a 4% sodium hydroxide solution (6.3.1.4) from a graduated pipette until a pink color appears for 30 s. coloring. Record the volume of the sodium hydroxide solution consumed and, if necessary, recalculate it by the volume of the aliquot of the sample taken for the determination according to 6.3.1.11.2. Discard the aliquot used to find the volume of the sodium hydroxide solution.

6.3.1.11.2 If the water sample was not preserved during sampling, add 2 ml of a 4% sodium hydroxide solution (6.3.1.4) to a 100 ml aliquot of the sample. stir, add 2 cm 3 of a 10% solution of magnesium sulfate (6.3.1.2). mix again and leave until sediment of magnesium hydroxide, with which manganese is coprecipitated, to the bottom of the glass. 8 depending on the expected value of the mass concentration of manganese, the volume of the aliquot can be increased to 500 cm 3. In this case, the volume of the added solutions of sodium hydroxide and magnesium sulfate is changed proportionally.

6.3.1.11.3 After settling, most of the solution is decanted over the precipitate, and the remainder is filtered through an obesopic filter "red penta". The filter cake is washed two to three times with distilled water and dissolved in 10 cm 3 of orthophosphoric acid solution (6.3.t.3), collecting the filtrate in a volumetric flask with a capacity of V? = 50 cm 3.

After cooling, the solution is brought to the mark with distilled water and the optical density is measured according to 6.3.2.

6.3.1.11.4 If, after adding the silver nitrate solution (6.3.1.5), a white precipitate or cloudiness forms, shake the flask containing the solution until then. until the precipitate gathers into lumps and the solution clears. Then the solution is centrifuged or filtered through a dry "red tape" filter into another volumetric flask with a capacity of 50 ml of e. the precipitate is washed 2-3 times with a small amount of distilled water and discarded. 0.3 g of ammonium persulfate or potassium persulfate (Section 5) is added to the filtrate with wash water. bring to a boil on a hotplate and incubate in a boiling water bath for 10 minutes. After cooling, the solution is brought to the mark with distilled water and the optical density is measured according to 6.3.2.

6.3.1.11.5 Prepare a blank sample in the same way, replacing the sample of the analyzed water with distilled water. If the water sample has been preserved (see 3.2). then, before analyzing a blank sample, nitric acid is added to it in the same volume as when the water sample was preserved.

6.3.2 Carrying out measurements

Calculate the arithmetic mean of the values obtained.

Dilution factor (calculated by the formula

where V t is the volume of the volumetric flask used to dilute the sample, cm 3:

V A is the volume of the sample aliquot taken for dilution, cm 3.

6.3.3 Processing of measurement results

6.3.3.2 In the absence of a computer (microprocessor) system for collecting and processing information, the mass concentration of manganese in the water sample X, mg / dm 3. calculated by the formula

where A is the optical density of the prepared water sample (6.3.2). optical density units;

A a is the optical density of a blank water sample (6.3.2). optical density units:

V 2 is the volume of the sample prepared according to 6.3.1.11.3, cm 3:

/ is the dilution factor (formula (5)].

b is the slope of the calibration characteristic [formula (1)]. (optical density units) dm 3 mg

Vt is the volume of the sample aliquot (original or diluted according to 6.3.2). taken to carry out the definition no 6.3.1.11.1 or 6.3.1.11.2. cm 3:

6.3.3.3 The arithmetic mean of the results of two measurements X and Xr is taken as the result of measurements of the mass concentration of manganese. obtained under repeatability conditions, when the condition

200 | X 1 -X 2 | £ g (X 1 - "- X 2), (7)

where r is the value of the repeatability limit according to table 1.

If condition (7) is not met, methods of checking the acceptability of measurement results are used. obtained under repeatability conditions, and establishing the final measurement result in accordance with GOST ISO 5725-6, subsection 5.2.

Note - When obtaining measurement results in two laboratories, the arithmetic mean value of the measurement results obtained in two laboratories X \ POS and X?

where R is the value of the reproducibility limit by tabts | e 1.

If condition (8) is not met, each laboratory shall follow the procedures in accordance with ISO 5725-6 clauses 5.2.2 to verify acceptability under reproducibility conditions. 5.3.2.2.

6.3.4 Metrological characteristics

The method provides for obtaining measurement results with metrological characteristics not exceeding the values given in Table 1. with a confidence level of P = 0.95.

Table 1

	Repeatability length	Reproducibility limit	Accuracy index
	(relative value	(otiositep value	(boundaries * relative
	acceptable discrepancy	acceptable discrepancy	error at
Measurement range of mass	between the two result-		probabilities

	under the same conditions, repeating	conditions reproducibly
	capacity at P "0.95)
			P - 0.95) 1 b. %
0.01 to 0.05 incl.
Behold. 0.05 to 5.00 incl.
* The established numerical values of the gram of the relative error correspond to the numerical
expanded uncertainty values (in relative units) 1) c. h with a coverage ratio k = 2.

If the water sample was diluted according to 6.3.2. then use the values of the metrological characteristics according to table 1 for the diluted sample.

6.3.5 Quality control of measurement results

Quality control of measurement results in the laboratory provides for monitoring the stability of measurement results taking into account the requirements of GOST ISO 5725-6 or recommendations (1).

6.3.6 Registration of measurement results

The measurement results are recorded in a test report, which is drawn up in accordance with the requirements of GOST ISO / IEC 17025. In this case, the test report must contain a reference to this standard indicating the measurement method.

Results of measurements of the mass concentration of manganese. mg / dm e. represent in the form

X ± 0.01-5-X at P = 0.95 or X ± 0.01 U cmH X at k = 2. (9)

where b - confidence limits of the relative measurement error of the mass concentration of manganese according to table 1,%;

Tsm "- relative expanded uncertainty. %, with a coverage factor of k = 2 according to table 1.

The numerical value of the measurement result must end with a digit of the same digit as the absolute value of the measurement accuracy, expressed in milligrams per cubic decimeter. The absolute value of the measurement accuracy indicator is represented by two significant digits, if the first digit does not exceed three. In other 8 cases, one significant digit is left.

6.4 Determination of manganese content with elimination of the interfering effect of chloride * ions

by evaporation with sulfuric acid (option 2)

6.4.1 Preparation for measurements - according to 6.3.1 with the following clarifications below.

6.4.1.1 Preparation of a solution of silver nitrate with a molar concentration of 0.1 mol / dm 3

In a conical flask with a capacity of 1500 cm 3 dissolve 17 g of silver nitrate in 1000 cm 3 of distilled water.

The shelf life of the solution in a dark glass container is no more than 1 month.

Note - It is allowed to prepare a smaller volume of solution, based on the need.

6.4.1.2 Preparation of a solution of sulfuric acid with a volume fraction of 33.3%

In a heat-resistant glass with a capacity of 1000 cm 3 is placed 500 cm 3 of distilled water and carefully, with stirring and external cooling, poured 250 cm 3 of concentrated sulfuric acid.

The shelf life of the solution is not limited.

6 4.1.3 Preparing water samples for analysis

In a porcelain bowl, add an aliquot of the water sample, measured with a cylinder, carefully add 5 cm 3 of the sulfuric acid solution (6.4.1.2) and evaporate first in a water bath and then on an electric stove to completely remove the acid.

Note - The recommended volume of a sample aliquot is 100 cm 3 with the expected value of the mass concentration of manganese in the sample from 0.05 to 1 mg / dm 3. At a higher manganese content (from 0.01 to 0.05 mg / dm 3), the volume of liquid should be increased to 250 500 cm 3, and at a higher (over 1 mg / dm 3), it should be reduced to 20 or 25 cm 3.

The dry residue is moistened with a small amount of distilled water, 5 cm 3 of concentrated nitric acid are added (Section 5). 10 cm 3 of hot distilled water and heated until the precipitate dissolves. The solution is transferred into a heat-resistant conical flask with a capacity of 50 cm 3, add 3 cm 3 of a solution of silver nitrate with a molar concentration of 0.1 mol / dm 3 (see 6.4.1.1), add 0.2 g of ammonium persulfate (section 5). heat to a boil and boil on a hotplate for 3 minutes.

The flask is cooled under a stream of cold water, its contents are quantitatively transferred into a volumetric flask with a capacity of 50 cm 3 and its volume is brought up to the mark with distilled water, then measurements are carried out according to 6.4.2.

6.4.1.4 Prepare a blank sample according to 6.3.1.11.5.

6.4.2 Carrying out measurements - according to 6.3.2 using the calibration characteristic according to 6.3.1.8. Distilled water is used as a reference solution.

6.4.3 Processing of measurement results - according to 6.3.3.

6.4.4 Metrological characteristics - according to 6.3.4.

6.4.5 Quality control of measurement results - according to 6.3.5.

6.4.6 Registration of measurement results - according to 6.3.6.

6.5 Determination of manganese content with elimination of the interfering effect of chloride ions

adding mercury sulfate (option 3)

6.5.1 Preparation for measurements - according to 6.3.1 with the following clarifications below.

6.5.1.1 Preparing mixed reagent

In a heat-resistant conical flask with a capacity of 1000 cm 3 add 200 cm 3 of distilled water. 40 (Concentrated nitric acid and 75 g of oxide mercury sulfate, then add 200 cm 3 of orthophosphoric acid (section 5) and (35 ± 1) g of silver nitrate (section 5). After cooling, the contents of the flask are transferred into a volumetric flask with a capacity of 1000 cm 3 and bring to the mark with distilled water.

The shelf life of the mixed reagent is no more than 6 months.

Note - It is allowed to prepare a smaller volume of the mixed reagent, depending on the need.

6.5.1.2 Preparing calibration solutions

In heat-resistant conical flasks with a capacity of 100 cm 3 pipettes add 0.00: 0.50: 1.00; 2.00: 4.00; 6.0; 8.0 and Yu.O cm 3 stock solution of manganese (6.3.1.1).

The contents of the flasks are diluted with distilled water to a volume of 80 - 90 cm 3 and 5 cm 3 of the mixed reagent (6.5.1.1), 1.0 g of ammonium persulfate (section 5) are added to each flask. bring the solution to a boil and boil on an electric stove for 3 minutes.

The flasks are quickly cooled under a stream of cold water, their contents are transferred into volumetric flasks with a capacity of 100 cm 3, brought to the mark with distilled water and mixed.

A manganese-free calibration solution (with a mass concentration of manganese equal to zero) is a blank for calibration. The mass concentration of manganese in the rest of the calibration solutions is 0.05, respectively; 0.Yu; 0.20: 0.40; 0.60; 0.80; 1.00 mg / dm 3.

The calibration solutions are prepared on the day of use.

6.5.1.3 Preparing the device

The preparation of the device for operation is carried out in accordance with the manual (instruction) for the operation of the device.

6.5.1.4 Calibration of the device - according to 6.3.1.8 using calibration solutions according to 6.5.1.2. verification of the acceptability of the calibration characteristic - according to 6.3.1.9, control of the stability of the calibration characteristic - according to 6.3.1.10.

6.5.1.5 Preparing water samples for analysis

In a heat-resistant conical flask with a capacity of 100, 250 or 500 cm 3, add an aliquot of a water sample with a cylinder, add 1 drop of hydrogen peroxide (Section 5). 5 cm 3 of the mixed reagent (6.5.1.1) and the sample is concentrated by evaporation on a hotplate to 90 cm 3 or diluted with distilled water to the same volume. Then add 1.0 g of ammonium persulfate (section 5) and bring the solution to a boil on an electric hot plate and boil for 3 minutes.

The flask is cooled under a stream of cold water, its contents are transferred into a volumetric flask with a capacity of 100 cm 3, brought to the mark with distilled water and mixed.

Note - The recommended volume of an aliquot of the sample is 100 cm 3 with the expected value of the mass concentration of manganese in the sample from 0.05 to 1 mg / dm 3. At a lower manganese content (from 0.01 to 0.05 mg / dm 3), the volume of a / quota should be increased to 250 * 500 cm 3, and at a higher (over 1 mg / dm 3) - reduced to 20 or 25 cm 3.

6.5.1.6 Prepare a blank sample according to 6.3.1.11.5.

6.5.2 Carrying out measurements - according to 6.3.2 using the calibration characteristic according to 6.5.1.4. Distilled water is used as a reference solution.

6.5.3 Processing of measurement results - according to 6.3.3.

6.5.4 Metrological characteristics - cl 6.3.4.

6.5.5 Quality control of measurement results - in accordance with 6.3.5.

6.5.6 Registration of measurement results - according to 6.3.6.

7 Determination of manganese content using formaldoxime (method B)

7.1 The essence of the method

The essence of the method is the formation of a complex compound of manganese with al-doxyme in an alkaline medium, followed by measuring the optical density of the solution and calculating the mass concentration of manganese in the water sample. When using a device equipped with a monochromator. set the working wavelength to 455 nm. when using filter devices, select a filter that has an absorption maximum in the region of (440 ± 20) nm.

7.2 Interfering influences

Iron (II) ions form a violet complex with formaldoxime. which interferes with the determination of manganese. This influence is eliminated during sample preparation by adding solutions of sodium ethyl acetate-mintetraacetate (7.3.1). a mixed solution of hydroxylamine hydrochloride and ammonia (7.3.5) and Mohr's salt (7.3.7). containing iron (II) ions. into all calibration solutions, blank and aliquot of water sample.

The presence of 1 mg / dm 3 cobalt (which is unlikely for water within the scope of this standard) gives a response equivalent to 40 μg / dm 3 manganese.

In the presence of calcium, orthophosphate ions with a content above 2 mg / dm 3 (in terms of phosphorus) may underestimate the results. The combined presence of calcium and magnesium with a total mass concentration of more than 300 mg / dm 3 causes an overestimation of the results. These interfering influences are eliminated when preparing a water sample according to 7.3.13.

7.3 Preparation for measurements

7.3.1 Preparation of a solution of sodium ethyl diamine tetraacetate with a molar concentration of 0.24 mol / dm e

In a volumetric flask with a capacity of 1000 cm 3, half filled with water, add 90 g of Trilon B. add 19 g of sodium hydroxide and, after complete dissolution, bring to the mark with distilled water.

Note - Similarly, you can obtain the specified solution by dissolving in distilled water 109 g of tetrahydrate (CtoHwN ^ Na ^^ MjO) or 100 g of dihydrate (C, 0 H, rN.Na4O e -2HyO) tetrahydrogen salt of ethylenediaminetetraacetic acid in distilled water and bring to distilled water marks.

7.3.2 Preparation of formaldoxime solution

In a volumetric flask with a capacity of 100 cm 3, add 50 cm 3 of distilled water, add 10 g of hydroxylamine hydrochloride and after its dissolution add 5 cm 3 of an aqueous solution of formaldehyde (formalin) and bring to the mark with distilled water.

The shelf life of the solution at a temperature from 2 ° C to 8 * C is no more than 1 month.

7.3.3 Preparation of a solution of hydroxylamine hydrochloride with a molar concentration of 6 mol / dm 3

In a volumetric flask with a capacity of 100 cm 3 add 42 g of hydroxylamine hydrochloride, dissolve in distilled water and then bring to the mark with distilled water.

The shelf life of the solution at a temperature of 2 ° C to 8 ° C is no more than 1 month.

7.3.4 Preparation of ammonia solution with molar concentration of 4.7 mol / dm 3

In a volumetric flask with a capacity of 200 cm 3, add 50 cm 3 of distilled water, add 70 cm 3 of concentrated aqueous ammonia solution (section 5) and bring to the mark with distilled water.

The shelf life of the solution in a tightly closed container made of polymer material is no more than 2

7.3.5 Preparation of a mixed solution of hydroxylamine hydrochloride and ammonia

Mix equal volumes of the solutions of ammonia (7.3.4) and hydroxylamine hydrochloride (7.3.3).

The shelf life of the solution at a temperature of 2 s C to 8 ° C in a tightly closed container made of polymeric material is no more than 7 days.

7.3.6 Preparation of a solution of sulfuric acid with a molar concentration of about 3 mol / dm 3

In a heat-resistant glass with a capacity of 1000 cm 3, 750 cm 3 of distilled water is added, carefully with stirring and, if necessary, cooling add 170 cm 3 of concentrated sulfuric acid. The contents of the glass are allowed to cool, transferred to a volumetric flask with a capacity of 1000 cm 3 and brought to the mark with distilled water.

The shelf life of the solution is no more than 1 year.

7.3.7 Preparation of Mohr's salt solution of mass concentration 700 mg / dm 3

Into a volumetric flask with a capacity of 1000 cm 3 add 500 cm 3 of distilled water, add 700 mg of Mohr's salt ((NHifeFefSO ^? 6HgO], after dissolution add 1 cm 3 of sulfuric acid solution (7.3.6) and bring to the mark with distilled water.

The shelf life of the solution at a temperature of 2 ° C to 8 J C in a dark place is no more than 3 months.

7.3.8 Preparation of a sodium hydroxide solution with a molar concentration of 4 mol / dm 3

In a glass or conical flask, place from 500 to 600 cm 1 of distilled water, add 160 g of sodium hydroxide and, after complete dissolution, transfer to a volumetric flask with a capacity of 1000 cm 3 and bring to the mark with distilled water.

The shelf life of the solution in a container made of polymeric material is no more than 2 months.

7.3.9 Preparation of an initial solution of manganese with a mass concentration of 100 mg / dm 3

In a volumetric flask with a capacity of 50 cm 3 add 5 cm 3 of a standard sample of the composition of a solution of manganese (II) ions. add 0.5 ml of sulfuric acid solution (7.3.6). bring the volume in the flask to the mark with distilled water and mix.

The shelf life of the solution is no more than 3 months.

7.3.10 Preparation of a working solution of manganese with a mass concentration of 5 mg / dm 3

Into a volumetric flask with a capacity of 50 cm 3 add 2.5 cm 3 of the stock solution of manganese (7.3.9). add 0.5 ml of sulfuric acid solution (7.3.6) and make up to the mark with distilled water.

The shelf life of the solution is no more than 1 month.

7.3.11 Preparation of calibration solutions

7.3.11.1 Preparation of manganese calibration solutions in the mass concentration range from 0.05 to 1.00 mg / dm 3

Pipettes 0.0; 0.5; 1.0; 2.0; 4.0; 6.0; 8.0 and 10.0 cm 3 of the working manganese solution according to 7.3.10. add 0.5 cm 3 of a sulfuric acid solution according to 7.3.6 and bring to the mark with distilled water. The mass concentration of manganese in the working calibration solutions is, respectively, 0.00: 0.05: 0.10: 0.20: 0.40: 0.60: 0.80 and 1.00 mg / dm 3.

7 3.11.2 Preparation of calibration solutions for the mass concentration range of manganese from 0.5 to 5.0 mg / dm 3

In a row of seven volumetric flasks with a capacity of 50 cm 3 each add 0.00: 0.25: 0.50: 1.00: 1.50; 2.00 and 2.50 cm 3 of the original manganese solution according to 7.3.9. add 0.5 cm 3 of a sulfuric acid solution according to 7.3.6 and bring to the mark with distilled water. The mass concentration of manganese in the calibration solutions is 0.0, respectively; 0.5; 1.0; 2.0: 3.0: 4.0 and 5.0 mg / dm 3.

Calibration solutions are prepared before use.

7.3.11.3 Processing of calibration solutions to form a colored compound

Transfer the calibration solutions (7.3.11.1 and 7.3.11.2) into conical flasks with a capacity of 100

Into each conical flask with calibration solutions (7.3.11.1. 7.3.11.2) add 1 ml of Mohr's solution (II) (7.3.7). 2 cm 3 of ethylenediamitetraacetate solution (7.3.1) and stir, then add 1 cm 3 of formaldoxime solution (7.3.2) and immediately add 2 cm 3 of sodium hydroxide solution (7.3.8).

The contents of each flask are thoroughly mixed and after 5 - 10 minutes add to each flask, stirring its contents. 3 cm 3 of a mixed solution of hydroxylamine hydrochloride and ammonia (7.3.5). The solutions are kept at room temperature for at least 1 hour but not more than 4 hours and then measurements are carried out according to 7.3.12.

Calibration solutions that do not contain manganese (with a mass concentration of manganese equal to zero) are a blank sample for calibration.

7.3.12 Calibration of the device - according to 6.3.1.8 using calibration solutions processed according to 7.3.11.3, and establishing separate calibration characteristics for the range from 0.05 to 1.00 mg / dm 3 using cuvettes with an absorbing layer thickness of 4 to 10 cm (recommended value 5 cm) and from 0.5 to 5.0 mg / dm 3 using cuvettes with an absorbent layer thickness of 1 cm. The absorbance value of the blank sample for calibration against distilled water is used when checking the acceptability of the absorbance of the blank sample according to 7.3.14.

Checking the acceptability of the calibration characteristics in accordance with 6.3.1.9. control of the stability of the calibration characteristics - according to 6.3.1.10.

7.3.13 Preparing water samples

7.3.13.1 If the sample has not been preserved, then it is acidified in accordance with 3.3.

7.3.13.2 If the expected value of the mass concentration of manganese in the sample is not less than 0.05 mg / dm 3. then take an aliquot of the analyzed sample (3.3. 7.3.13.1) with a volume of 50 cm 3 with a cylinder and transfer it to a conical flask with a capacity of 100 cm 3.

7.3.13.3 If the expected value of the mass concentration of manganese in the water sample is less than 0.05 mg / dm 3. then take an aliquot of the analyzed water (3.3. 7.3.13.1) with a volume of 250 cm 3 with a cylinder. Place the sample in an evaporation dish and evaporate in a water bath or electric stove, if necessary in several steps, to a volume of about 30 cm 3. During evaporation on a hot plate, the sample should not boil to avoid splashing. The one stripped off sample is transferred into a conical flask with a capacity of 100 cm 3, add 2.5 cm 3 of sodium hydroxyl solution (7.3.8) and dilute to the mark with distilled water.

Make sure that after adding the sodium hydroxide solution the pH of the sample does not exceed 3 (control with universal indicator paper). If this condition is not met, then add dropwise a solution of sulfuric acid according to 7.3.6 until a pH value of less than 3 is reached.

7.3.13.4 To the sample (7.3.13.2, 7.3.13.3) add (225 ± 25) mg of potassium persulfate or sodium persulfate as an oxidizing agent (Section 5) and boil for 40 min. cool, transfer the contents of the flask into a volumetric flask with a capacity of 50 cm 3, bring to the mark with distilled water and add about 0.5 g of sodium sulfite (Section 5) to remove excess oxidant.

7.3.13.5 Transfer the sample processed according to 7.3.13.4 into a conical flask with a capacity of 100 ml.

Add 1 ml of Mohr's salt solution (7.3.7) to the contents of the conical flask. 2 cm 3 of sodium ethylenediaminetetracetate solution (7.3.1) and mix, then add 1 cm 3 of formaldoxime solution (7.3.2) and immediately add 2.5 cm 3 of sodium hydroxide solution (7.3.6) and mix thoroughly.

After 5-10 mms, add to the analyzed sample with stirring. 3 cm 3 of a mixed solution of hydroxylamine hydrochloride and ammonia (7.3.5) and incubate at room temperature for at least 1 h.

Turbid samples are centrifuged before measurements in accordance with 7.4.

7.3.14 Analysis of a blank

Distilled water is used as a blank sample, the volume of which is equal to the volume of an aliquot of the analyzed water. Prepare a blank sample for measurements according to 7.3.13 simultaneously with water samples.

If the optical density of the prepared blank sample, measured relative to distilled water, differs significantly (by more than 0.02 optical density units) from the optical density of the blank sample for calibration (7.3.11.3). measured with respect to distilled water, the reasons for this difference should be established and eliminated. The most likely reason is contamination of the chemicals used and / or distilled water, insufficient cleanliness of the dishes.

7.4 Carrying out measurements - similarly to 6.3.2, taking into account the requirements of 7.3.12. A blank sample prepared according to 7.3.14 is used as a reference solution.

7.5 Processing of measurement results according to 6.3.3 using metrological characteristics according to table 2.

7.6 Metrological characteristics

The method provides for obtaining measurement results with metrological characteristics not exceeding the values given in Table 2. with a confidence level of P = 0.95.

table 2

Measurement range of mass concentration of manganese, mg / dm *	The repeatability limit of the allowed discrepancies. obtained about uelo - 0.95) g	Reproducibility limit acceptable discrepancy between the two results reproducibility conditions at P 0.95) R.%	Accuracy indicator ((early * relative favorability with probability
0.01 to 0.05 incl.
St. 0.05 to 0.20 incl.
St. 0.2 to 5.0 incl.
* The established numerical values of the boundaries of the relative error correspond to the numerical values of the expanded uncertainty (in small units) (Jet. With a coverage factor k = 2.

If the water sample was diluted (6.3.2. 7.4) then use the values of the metrological characteristics according to Table 2 for the diluted sample.

7.7 Quality control of measurement results - according to 6.3.5.

7.8 Registration of measurement results - according to 6.3.6 using metrological characteristics according to Table 2.

Bibliography

Recommendations for Interstate Standardization RMG 76-2004. State system for ensuring the uniformity of measurements. Internal quality control of the results of quantitative chemical analysis

UDC 628.1.033: 006.354 MKS 13.060.50 TN VED 220100000

Key words: drinking water, water from underground sources, water from surface sources, mass concentration of manganese, photometric methods, tests

Signed for printing 03.03.2015. Format 60x84%.

Uel. print l. 2.33. Circulation 31 copies. Zach. 1096

Prepared on the basis of the electronic version provided by the developer of the standard

FSUE STANDARTENFORM *. 123995 Moscow. Granatny lane .. 4.

GOST 4974 method a edition. The shelf life of the solution is not limited

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Drinking water. Determination of manganese content by photometric methods

TIN-ZINC BRONZE BARS

Technical conditions

Foreword

Method of ultrasonic testing of press sinkers

1 area of ​​use

2 Normative references

5 Technical requirements

6 Acceptance rules

7 Methods of inspection and testing

8 Marking, packaging, transportation and storage

9 Manufacturer's warranty

Diameters, cross-sectional area and linear density of drawn and extruded bars

1 area of ​​use

2 Normative references

3 Sampling

4 Requirements for measurement conditions

INTERSTATE

STANDARD

DRINKING WATER

Determination of manganese content by photometric methods

(ISO 6333: 1986, NEO)

Foreword

Information about the standard

5 REPLACE GOST 4974-72

1 (C,) 2

! ^ - 4s0.10. (3)

I 0 - "- ~ C" I $ 0.12. (4)

The shelf life of the solution is not limited.

1 area of use

1 area of use