3.2.1; 3.10.1

3.2.1; 3.3.1; 3.4

3.2.1; 3.3.1; 3.10.1

3.2.1; 3.3.1

3.2.1; 3.3.1; 3.10.1

3.2.1; 3.3.1

TU 6-09-07-1579-87

3.2.1; 3.3.1

TU 6-09-3736-79

TU 6-09-5169-84

TU 6-09-5360-87

6. The limitation of the validity period was removed by the Decree of the State Standard of the USSR of 17.05.91 N 706

7. REPUBLICATION (October 1993) with Amendments No. 1, 2, approved in March 1986, May 1991 (IUS 6-86, 8-91)

This standard applies to metaphosphoric acid, which is colorless transparent plates or sticks that deliquesce in air and become dull over time; soluble in water. The drug consists of a mixture of metaphosphoric acid and its sodium salt (stabilizer).

HPO formula.

Relative molecular weight (according to international atomic masses 1985) - 79.98.

The requirements of this standard, in addition to the requirements for mass fraction arsenic are mandatory.

1. TECHNICAL REQUIREMENTS

1.1. Metaphosphoric acid shall be manufactured in accordance with the requirements of this International Standard. technological regulations approved in the prescribed manner.

1.2. In terms of chemical parameters, metaphosphoric acid must comply with the requirements and standards specified in the table.


Name of indicator
	Pure (h) OKP 36 1213 0031 08
1. Mass fraction metaphosphoric acid (HPO), %, not less than
2. Mass fraction of sodium salt of metaphosphoric acid (NaPO),%, no more
3. Mass fraction of sulfates (SO),%, no more
4. Mass fraction of nitrates (NO),%, no more
5. Mass fraction of chlorides (Cl),%, no more
6. Mass fraction of iron (Fe),%, no more
7. Mass fraction of heavy metals (Pb),%, no more
8. Mass fraction of arsenic (As),%, no more
9. Substances that restore potassium permanganate	must withstand test according to item 3.10

2a. SAFETY REQUIREMENTS

2a.1. Metaphosphoric acid causes irritation of mucous membranes and skin.

2a.2. When working with the drug should be used individual funds protection in accordance with standard industry regulations, as well as to observe the rules of personal hygiene.

2a.1; 2a.2. (Introduced additionally, Rev. N 1).

2a.3. Premises in which work with the drug is carried out must be equipped with general supply and exhaust ventilation. The analysis of the drug should be carried out in a laboratory fume hood.

2. ACCEPTANCE RULES

2.1. Acceptance rules - according to GOST 3885-73.

2.2. The mass fraction of arsenic according to subparagraph 8 of the table is determined only at the request of consumers.

3. METHODS OF ANALYSIS

3.1a. General instructions for the analysis - in accordance with GOST 27025-86.

Weighing using laboratory scales general purpose types VLR-200 g and VLKT-500 g-M or VLE-200 g.

It is allowed to use other measuring instruments with metrological characteristics and equipment with technical specifications not worse, as well as reagents in quality not lower than those specified in this standard.

3.1. Samples are taken according to GOST 3885-73. The mass of the average sample must be at least 265 g.

3.1a; 3.1. (Changed edition, Rev. N 2).

3.2. Determination of the mass fraction of metaphosphoric acid

3.2.1. Reagents, solutions, apparatus and utensils:

bromcresol green (indicator) according to TU 6-09-07-1579-87, solution with a mass fraction of 0.2%; prepared as follows: 0.200 g of bromcresol green is dissolved in a mixture consisting of 6 ml of sodium hydroxide solution with a concentration of 0.1 mol / dm and 5 ml of alcohol. The volume of the solution is adjusted with water to 100 cm 3 and mixed;

buffer mixture with pH 4.6; prepared as follows: 100 ml of phosphate-citrate buffer solution is placed in a conical flask and 0.5 ml of bromcresol green solution is added. To prevent the development of bacteria, the buffer mixture is sterilized by heating to 60-70 ° C, 0.01 g of thymol is added and mixed. The solution is stored in a flask closed with a rubber stopper in a dark place;

distilled water according to GOST 6709-72;

sodium hydroxide according to GOST 4328-77, concentration solutions (NaOH) = 0.1 mol / dm (0.1 N) and 0.2 mol / dm (0.2 N); prepared according to GOST 25794.1-83;

rectified technical ethyl alcohol in accordance with GOST 18300-87, premium;

thymol according to TU 6-09-3736-79, part;

phosphate-citrate buffer solution pH 4.6; prepared according to GOST 4919.2-77;

burette 1-2-50-0.1 according to GOST 29251-91;

flask Kn-2-250-34 THS according to GOST 25336-82;

pipettes 4(5)-2-1(2) and 6(7)-2-5(10) according to GOST 29227-91;

cylinder 1(3)-100 according to GOST 1770-

3.3.2. Conducting an analysis

About 3.0000 g of the drug is placed in a beaker, 125 ml of water and 10 ml of nitric acid are added. The solution is heated to boiling and boiled for 30 minutes, topping it up with water during boiling to the original volume. After cooling, 1 cm3 of a solution of 2,4-dinitrophenol and a solution of sodium hydroxide with a mass fraction of 30% are added to the solution until a slightly yellow color appears and cooled again. A solution of hydrochloric acid is added to the cooled solution until the color disappears, and then another 1-2 cm of acid. The contents of the beaker are transferred to a volumetric flask, the volume of the solution is adjusted to the mark with water and mixed.

Place 25 ml of the prepared solution into two conical flasks with a pipette with a capacity of 25 ml, add 50 ml of water to each flask and mix.

The solution in one flask is titrated from a burette with a solution of sodium hydroxide at a concentration of 0.2 mol/dm in the presence of 0.2 ml of a solution of bromocresol green until the color matches the color of the buffer mixture.

The solution in the second flask is titrated from a burette with a solution of sodium hydroxide with a concentration of 0.2 mol / dm in the presence of a mixed indicator until the crimson color of the solution changes through yellow and orange to red.

3.3.3. Results processing

The mass fraction of the sodium salt of metaphosphoric acid () as a percentage is calculated by the formula

where is the volume of a solution of sodium hydroxide with a concentration of exactly 0.2 mol / dm, used for titration in determining the mass fraction of metaphosphoric acid according to clause 3.2.3, cm;

The volume of a sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, used for titration with a mixed indicator, cm;

The volume of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm3, used for titration with an indicator of bromcresol green, cm;

The weight of the sample of the drug when determining the mass fraction of metaphosphoric acid according to clause 3.2.3, g;

Weight of sample of the preparation, g;

0.02039 - the mass of the sodium salt of metaphosphoric acid, corresponding to 1 cm 3 of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, g.

The result of the analysis is taken as the arithmetic mean of the results of two parallel determinations, the absolute discrepancy between which does not exceed the allowable discrepancy equal to 1%.

Permissible absolute total error of the analysis result ± 0.7% at a confidence level

3.4. The determination of the mass fraction of sulfates is carried out according to GOST 10671.5-74 by the visual nephelometric method (method 1). At the same time, 50.00 g of the drug is placed in a glass with a capacity of 400 cm 3 and dissolved when heated in 200 cm 3 of water. The solution is boiled for 2 hours, topping it up with water during boiling to the original volume. After cooling, the solution is transferred into a volumetric flask with a capacity of 250 ml, the volume of the solution is adjusted to the mark with water and mixed - solution A.

Solution A is kept for the determination of nitrates according to paragraph 3.5, chlorides according to paragraph 3.6, iron according to paragraph 3.7, heavy metals according to paragraph 3.8, arsenic according to paragraph 3.9.

10 cm 3 of solution A (corresponding to 2.00 g of the preparation) are taken with a pipette, filtered, if it is cloudy, through an ash-free blue tape filter, previously washed three times hot water, placed in a beaker or conical flask and bring the volume of the solution to 26 cm3 with water. Further, the determination is carried out according to GOST 10671.5-74 without adding a hydrochloric acid solution, using an alcoholic solution of barium chloride instead of water. A solution of barium chloride is prepared as follows: 5.00 g of barium chloride is dissolved in a mixture consisting of 66.5 cm3 of water and 28.5 cm ethyl alcohol premium (GOST 18300-87).

The drug is considered to comply with the requirements of this standard if the observed opalescence of the analyzed solution is not more intense than the opalescence of a solution containing in the same volume: 0.02 mg SO, 1 ml hydrochloric acid solution with a mass fraction of 10%, 3 ml starch solution and 3 ml alcohol solution chloride b

3.3.1-3.3.3; 3.4. (Changed edition, Rev. N 1, 2).

3.5. The determination of the mass fraction of nitrates is carried out according to GOST 10671.2-74 using indigo carmine. At the same time, 10 cm3 of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a conical flask with a capacity of 50-100 cm3, and then the determination is carried out according to GOST 10671.2-74.

The drug is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not weaker than the color of a solution containing in the same volume: 0.01 mg of NO, 1 ml of sodium chloride solution, 1 ml of indigo carmine solution and 12 ml of concentrated sulfuric acid.

(Changed edition, Rev. N 2).

3.6. Determination of the mass fraction of chlorides is carried out according to GOST 10671.7-74 visual-nephelometric (method 2) method. At the same time, 20 cm3 of solution A (corresponding to 4 g of the drug) prepared according to clause 3.4 is taken with a pipette, filtered, if it is cloudy, through an ash-free "blue tape" filter, previously washed with a hot solution of nitric acid with a mass fraction of 1%, placed in a conical flask with a capacity of 100 cm3, the volume of the solution is adjusted to 30 cm3 with water, and then the determination is carried out to GOST 10671.7-74 without adding a solution of nitric acid.

The drug is considered to comply with the requirements of this standard if the opalescence of the analyzed solution is not more intense than the opalescence of a solution containing 0.040 mg CI, 2 ml of nitric acid solution and 1 ml of silver nitrate solution in the same volume.

3.7. The determination of the mass fraction of iron is carried out according to GOST 10555-75 by the sulfosalicylic method. At the same time, 2 cm3 of solution A (corresponding to 0.4 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a volumetric flask with a capacity of 50 cm3, the volume of the solution is adjusted to 21 cm3 with water, and then the determination is carried out according to GOST 10555-75 without adding hydrochloric acid acids.

The preparation is considered to comply with the requirements of this standard if the mass of iron does not exceed 0.008 mg.

It is allowed to carry out the determination visually.

In case of disagreement in the assessment of the mass fraction of iron, the analysis is carried out photometrically.

3.6; 3.7. (Changed edition, Rev. N 1, 2).

3.8. The determination of heavy metals is carried out according to GOST 17319-76 by the hydrogen sulfide method. At the same time, 10 ml of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a 100 ml conical flask (with ground or rubber stopper), neutralized with an ammonia solution with a mass fraction of 10% according to universal indicator paper to pH 7 and bring the volume of the solution with water to 30 cm. Further, the determination is carried out according to GOST 17319-76.

The preparation is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not more intense than the color of the solution containing in the same volume; 0.01 mg Pb, 1 cm acetic acid, 1 cm solution of ammonium acetate and 10 cm hydrogen sulfide water.

(Changed edition, Rev. N 2).

3.9. Determination of the mass fraction of arsenic is carried out according to GOST 10485-75 visual method using bromine-mercury paper in a sulfuric acid environment. At the same time, 10 cm 3 of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into the flask of the device for determining arsenic and 20 cm 3 of water are added. Further, the determination is carried out according to GOST 10485-75.

The drug is considered to comply with the requirements of this standard if the observed color of bromine-mercury paper from the analyzed solution is not more intense than the color of bromine-mercury paper from a solution prepared simultaneously with the analyzed one and containing in the same volume: 0.004 mg As, 20 ml of sulfuric acid solution, 0 .5 ml of a solution of stannous chloride and 5 g of zinc.

(Changed edition, Rev. N 1, 2).

3.10. Potassium permanganate reducing agent test

3.10.1. Reagents, solutions, equipment:

distilled water according to GOST 6709-72, distilled in the presence of potassium permanganate;

potassium permanganate according to GOST 20490-75, concentration solution (KMnO) = 0.01 mol / dm of water when heated. Then 1 cm3 of a solution of potassium permanganate is added, the solution is heated to a boil and kept in a water bath for 10 minutes.

The preparation is considered to comply with the requirements of this International Standard if the observed pink color of the analyzed solution does not disappear within 5 minutes.

3.10.1; 3.10.2. (Changed edition, Rev. N 2).

4. PACKAGING, LABELING, TRANSPORT AND STORAGE

4.1. The drug is packaged and labeled in accordance with GOST 3885-73.

Types and types of containers: 2-1, 2-4, 2-9.

Packing groups: V and VI.

(Changed edition, Rev. N 1).

4.2. The drug is transported by all means of transport in accordance with the rules for the carriage of goods in force on this type of transport.

4.3. The drug is stored in the manufacturer's packaging in covered warehouses.

5. MANUFACTURER WARRANTY

5.1. The manufacturer guarantees the compliance of metaphosphoric acid with the requirements of this standard, subject to the conditions of transportation and storage.

5.2. Guarantee period storage - 1 year from the date of manufacture.

5. (Changed edition, Rev. N 1).

6. (Deleted, Rev. N 1).

Electronic text of the document
prepared by CJSC "Kodeks" and checked against:
official publication
M.: Publishing house of standards, 1994

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STATE STANDARD

UNION SSR

REAGENTS

METAPHOSPHORIC ACID

Official edition

STANDARDS PUBLISHING HOUSE

UDC 546.185-323-41:006.354 Group L51

STATE STANDARD OF THE UNION OF THE SSR

reactive

METAPHOSPHORIC ACID

Specifications

reagents. Mctaphosphoric acids. Spcsifications

OKP 26 1213 0030 09

Introduction date 01.01.77

This standard applies to metaphosphoric acid, which is colorless transparent plates or sticks that deliquesce in air and become dull over time; soluble in water. The drug consists of a mixture of metaphosphoric acid and se sodium salt (stabilizer).

Formula NRoz.

Relative molecular weight (according to international atomic masses 1985) - 79.98.

The requirements of this standard, in addition to the requirements for the mass fraction of arsenic, are mandatory.

(Changed edition, Rev. N9 1, 2).

1. TECHNICAL REQUIREMENTS

1.1. Metaphosphoric acid must be manufactured in accordance with the requirements of this standard according to the technological regulations approved in the prescribed manner.

1.2. Chemically, metaphosphoric acid

must comply with the requirements and standards specified in the table._ _______________

Edition official reprint prohibited

Reissue with changes

P. 10 GOST 84J~36

5. MANUFACTURER WARRANTY

5.1. The manufacturer guarantees the compliance of metaphosphoric acid with the requirements of this standard, subject to the conditions of transportation and storage.

5.2. Guaranteed shelf life - 1 year from the date of manufacture.

5. (Changed edition, Rev. No. 1).

6. (Deleted, Rev. No. 1).

GOST Ml-7* S I

INFORMATION DATA

1. DESIGNED AND INTRODUCED by the Ministry chemical industry USSR

DEVELOPERS

G. V. Gryaznov, V. G. Brudz, I.L. Roteiberg, V.N. Smorodinskaya, L.V. Kndnyarova, K.P. Lesina

2. APPROVED AND INTRODUCED BY Decree State Committee standards of the Council of Ministers of the USSR dated 01/28/76 No. 229

3. Period of inspection - 1996 Periodicity of inspection - 5

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

	Item number
	3.2.1; 3.3.1; 3.10.1











	3.2.1 3.3.1; 3.4

	3.2.1; 3.3.1; 3.IO.I

b. The validity period was canceled by the Decree of the State Standard of the USSR of May 17, 1991 No. 706

7.Persian edition (October 1993) with Amendments No. 1, 2, approved in March 1986, May 1991 (IUS 6-86, 8-91)

Editor /G. A Afanasenko Technical editor O.I. Vlasova Proofreader L/. From Kabashov

Uel. oven l. 1.0. C9I8.

Rented * set 08.12.93. Signed and stamped 12/22/93. Uel. kr.-ott. 1.0. Uch. ied. l. 0.63. Circulation 464 eU. Zek.

Order "Badge of Honor" Standards Publishing House,

107076, Moscow, Kolodezny per., 14.

Typed at the PEDM Standards Publishing House.

Type. "Moscow printer". Moscow, Lilnn per., 6. Zak.S^UB

Pvimekpmmig pomtel"
Pvimekpmmig pomtel"	Pure (h) OKL 26 1213 0031 Oy
1 mass fraction of mstaphosphoric acid (WPO3),
%, ns msss
2 Mass fraction of sodium salt of mstaphosphoric
acids (ChaROz), %, no more
3 Mass fraction of sulfates (SO4). %, ns more
4 Mass fraction of nitrates (NHOz), %, ns more
5 Mass fraction of chlorides (С1), %. ns over
6. Mass fraction of iron (Fc>, %, no more
7 Mass fraction of heavy metals (Pb), %, not

8 Mass fraction of arsenic (As),%, no more
9 Substances that reduce manganese acid
	withstand
	test according to item EVIL

(Changed edition, Rev. N9 1).

2a. SAFETY REQUIREMENTS

2a. 1. Metaphosphoric acid causes irritation of mucous membranes and skin.

2a.2. When working with the drug, you should use personal protective equipment in accordance with standard industry standards, as well as observe the rules of personal hygiene.

2aL; 2a.2. (Introduced additionally, Rev. N6 1).

2a.Z, Premises in which work with the drug is carried out must be equipped with a general supply and exhaust ventilation. The analysis of the drug should be carried out in a laboratory fume hood.

2. ACCEPTANCE RULES

2.2. The mass fraction of arsenic according to subparagraph 8 of the table is determined only at the request of consumers.

GOST 34G-76 C 3

3. METHODS OF ANALYSIS

3.1a. General instructions for the analysis - in accordance with GOST 27025-86.

When weighing, general-purpose laboratory scales of the VLR-200 g and VLKT-500 g-M or VLE-200 g types are used.

It is allowed to use other measuring instruments with metrological characteristics and equipment with technical characteristics not worse, as well as reagents of a quality not lower than those specified in this standard.

GOST 18300-87, premium;

thymol according to TU 6-09-3736-79, part;

phosphate-citrate buffer solution pH 4.6; prepared according to GOST 4919.2-77;

3.2.2. Conducting an analysis

About 0.5000 g of the drug is placed in a conical flask, 70 cm 3 of water are added, heated to boiling and boiled for 20-30 minutes, adding water during boiling to the initial volume. 0.5 cm 3 of a solution of bromcresol green is added to the cooled solution and titrated from a burette with a solution of sodium hydroxide with a concentration of 0.2 mol / dm 3 until the color of the analyzed solution changes from yellow to green and then to green-blue, coinciding with the color of the buffer mixture, used for comparison.

3.2.3. Results processing

The mass fraction of metaphosphoric acid (X) as a percentage is calculated by the formula

„ 7-0,01599*100

where V is the volume of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm 3 used for titration, cm 3; t is the weight of the sample of the preparation, g;

0.01599 - mass of metaphosphoric acid, corresponding to 1 cm 3 sodium hydroxide solution, concentration exactly 0.2 mol / dm 3, g;

Permissible absolute total error of the analysis result is ± 0.6% at a confidence level Р w 0.95. 3.2.1-3.2.3. (Changed edition, Rev. No. 1, 2).

3.3. Determination of the mass fraction of the sodium salt of metaphosphoric acid

3.3.1. Reagents, solutions, apparatus and utensils: bromcresol green (indicator) according to TU 6-09-07-1579-87, solution with a mass fraction of 0.2%; prepared according to clause 3.2.1; buffer mixture with pH 4.6; prepared according to clause 3.2.1; distilled water, not containing carbon dioxide; prepared according to GOST 4517-87;

2,4-dicytrophenal (a-dinitrophenol), solution with a mass fraction of 0.1%; prepared according to GOST 4919.1-77;

GOST $41-76 S. 5

mixed indicator, alcohol solution; prepare as follows: 0.100 g of methyl red and 0.600 g of phenolphthalein are placed in a conical flask and dissolved in 100 cm 3 of alcohol;

rectified technical ethyl alcohol in accordance with GOST 18300-87, premium;

phenolphthalein (indicator) according to TU 6-09-5360-87;

3.3.2. Conducting an analysis

About 3.0000 g of the drug is placed in a beaker, 125 cm 3 of water and 10 cm 3 of nitric acid are added. The solution is heated to boiling and boiled for 30 minutes, topping it up with water during boiling to the original volume. After cooling, 1 cm 3 of a solution of 2,4-dinitrophenol and a solution of sodium hydroxide with a mass fraction of 30% are added to the solution until a slightly yellow color appears and cooled again. A solution of hydrochloric acid is added to the cooled solution until the color disappears, and then another 1-2 cm 3 of acid. The contents of the beaker are transferred to a volumetric flask, the volume of the solution is adjusted to the mark with water and mixed.

Place 25 cm 3 of the prepared solution into two conical flasks with a pipette with a capacity of 25 cm 3, add 50 cm 3 of water to each flask and mix.

The solution in one flask is titrated from a burette with a solution of sodium hydroxide with a concentration of 0.2 mol/dm 3 in the presence of 0.2 cm 3 of a solution of bromcresol green until the color matches the color of the buffer mixture.

The solution in the second flask is titrated from a burette with a sodium hydroxide solution with a concentration of 0.2 mol/dm 3 in the presence of a mixed indicator until the crimson color of the solution changes from yellow and orange to red.

3.3.3. Results processing

The mass fraction of the sodium salt of metaphosphoric acid (X\) as a percentage is calculated by the formula

_ (Kh-U 2) -0.02039-250-100 V 0.02039-100 LH "mi-25 t

where V is the volume of a solution of sodium hydroxide with a concentration of exactly 0.2 mol / dm, used for titration when determining the mass fraction of metaphosphoric acid according to clause 3.2.3, cm,

V\ is the volume of sodium hydroxide solution with a concentration of exactly 0.2 mol/dm 3 used for titration with a mixed indicator, cm 3 ;

V2 is the volume of a solution of sodium hydroxide with a concentration of exactly 0.2 mol / dm 3, used for titration with the bromocresol green indicator, cm, m is the mass of the sample of the drug when determining the mass fraction of metaphosphoric acid according to clause 3.2.3, g; t 1 is the weight of the sample of the drug, g;

0.02039 is the mass of the sodium salt of metaphosphoric acid, corresponding to 1 cm 3 of a sodium hydroxide solution with a concentration of exactly 0.2 mol / dm 3, g.

The result of the analysis is taken as the arithmetic mean of the results of two parallel determinations, the absolute discrepancy between which does not exceed the allowable discrepancy equal to 1%.

Permissible absolute total error of the analysis result is ± 0.7% at a confidence level Р w 0.95.

3.4. The determination of the mass fraction of sulfates is carried out according to GOST 10671.5-74 by the visual nephelometric method (method 1). By mouth, 50.00 g of the drug is placed in a glass with a capacity of 400 cm 3 and dissolved when heated in 200 cm 3 of water. The solution is boiled for 2 hours, topping it up with water during boiling to the original volume. After cooling, the solution is transferred into a volumetric flask with a capacity of 250 cm 3, the volume of the solution is adjusted to the mark with water and mixed - solution A.

Solution A is kept for the determination of nitrates according to paragraph 3.5, chlorides according to paragraph 3.6, iron according to paragraph 3.7, heavy metals according to paragraph 3.8, arsenic according to paragraph 3.9.

10 cm 3 of solution A (corresponding to 2.00 g of the drug) are taken

pipette, filtered if it is cloudy, through an ash-free “blue tape” filter, previously washed three times with hot water, placed in a beaker or conical flask and the volume of the solution is adjusted to 26 cm 3 with water. Further, the determination is carried out according to GOST 10671.5-74 without adding a solution of hydrochloric acid, using an alcohol solution of barium chloride instead of water. A solution of barium chloride is prepared as follows: 5.00 g of barium chloride is dissolved in a mixture consisting of 66.5 cm 3 of water and 28.5 cm 3 of premium ethyl alcohol (GOST 18300-87).

The drug is considered to comply with the requirements of this standard if the observed opalescence of the analyzed solution is not more intense than the opalescence of a solution containing in the same volume: 0.02 mg SO4, 1 cm 3 hydrochloric acid solution with a mass fraction of 10%, 3 cm 3 starch solution and 3 cm 3 alcohol solution of barium chloride.

3.3.1-3.3.3; 3.4. (Changed edition, Rev. No. 1, 2).

The preparation is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not weaker than the color of a solution containing in the same volume: 0.01 yg of NO3. 1 cm 3 sodium chloride solution, 1 cm 3 indigo carmine solution and 12 cm 3 concentrated sulfuric acid.

(Revised edition, Rev. No. 2).

The drug is considered to comply with the requirements of this standard if the opalescence of the analyzed solution is not more intense than the opalescence of a solution containing in the same

volume of 0.040 mg CI, 2 cm 3 solution of nitric acid and 1 cm 3 solution of silver nitrate.

The drug is considered to comply with the requirements of this standard, the network mass of iron will not exceed 0.008 mg.

It is allowed to carry out the determination visually.

In case of disagreement in the assessment of the mass fraction of iron, the analysis is carried out photometrically.

3.6; 3.7. (Changed edition, Rev. No. 1, 2).

3.8. The determination of heavy metals is carried out according to GOST 17319-76 by the hydrogen sulfide method. At the same time, 10 cm 3 of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a conical flask with a capacity of 100 cm 3 (with a ground or rubber stopper), neutralized with an ammonia solution with a mass fraction of 10% according to universal indicator paper to pH 7 and bring the volume of the solution with water to 30 cm 3 . Further, the determination is carried out according to GOST 17319-76.

The preparation is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not more intense than the color of the solution containing in the same volume; 0.01 mg Pb, 1 cm 3 acetic acid, 1 cm 3 ammonium acetate solution and 10 cm 3 hydrogen sulfide water.

GOST 841-76 Reagents. Metaphosphoric acid. Specifications (with Amendments No. 1, 2)

Adopted January 28, 1976
State Committee for Standards of the Council of Ministers of the USSR

GOST 841-76
Group L51
STATE STANDARD OF THE UNION OF THE SSR
Reagents
METAPHOSPHORIC ACID
Specifications
reagents. Metaphosphoric acids. Specifications
OKP 26 1213 0030 09
Introduction date 1977-01-01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of Chemical Industry of the USSR DEVELOPERS
G.V.Gryaznov, V.G.Brudz, I.L.Rotenberg, V.N.Smorodinskaya, L.V.Kidiyarova, K.P.Lesina
2. APPROVED AND INTRODUCED BY Decree of the State Committee for Standards of the Council of Ministers of the USSR dated 01/28/76 N 229
3. Period of inspection - 1996 Periodicity of inspection - 5 years
4. REPLACE GOST 841-64
5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS
Designation of the NTD to which the link is given Item numberGOST 1770-74 3.2.1; 3.3.1; 3.10.1GOST 3118-77 3.3.1GOST 3885-73 2.1; 3.1; 4.1GOST 4328-77 3.2.1; 3.3.1GOST 4461-77 3.3.1GOST 4517-87 3.3.1GOST 4919.1-77 3.3.1GOST 4919.2-77 3.2.1GOST 6709-72 3.2.1; 3.10.1GOST 10485-75 3.9GOST 10555-75 3.7GOST 10671.2-74 3.5GOST 10671.5-74 3.4GOST 10671.7-74 3.6GOST 17319-76 3.8GOST 18300-87 3.2.1; 3.3.1; 3.4GOST 20490-75 3.10.1GOST 25336-82 3.2.1; 3.3.1; 3.10.1GOST 25794.1-83 3.2.1; 3.3.1GOST 25794.2-83 3.10.1GOST 27025-86 3.1aGOST 29227-91 3.2.1; 3.3.1; 3.10.1GOST 29251-91 3.2.1; 3.3.1TU 6-09-07-1579-87 3.2.1; 3.3.1TU 6-09-3736-79 3.2.1TU 6-09-5169-84 3.3.1TU 6-09-5360-87 3.3.1
6. The limitation of the validity period was removed by the Decree of the State Standard of the USSR of 17.05.91 N 706
7. REPUBLICATION (October 1993) with Amendments No. 1, 2, approved in March 1986, May 1991 (IUS 6-86, 8-91)
This standard applies to metaphosphoric acid, which is colorless transparent plates or sticks that deliquesce in air and become dull over time; soluble in water. The drug consists of a mixture of metaphosphoric acid and its sodium salt (stabilizer).
HPO formula.
Relative molecular weight (according to international atomic masses 1985) - 79.98.
The requirements of this standard, in addition to the requirements for the mass fraction of arsenic, are mandatory.
1. TECHNICAL REQUIREMENTS
1.1. Metaphosphoric acid must be manufactured in accordance with the requirements of this standard according to the technological regulations approved in the prescribed manner.
1.2. In terms of chemical parameters, metaphosphoric acid must comply with the requirements and standards specified in the table.
2a. SAFETY REQUIREMENTS
2a.1. Metaphosphoric acid causes irritation of mucous membranes and skin.
2a.2. When working with the drug, you should use personal protective equipment in accordance with standard industry standards, as well as observe the rules of personal hygiene.
2a.1; 2a.2. (Introduced additionally, Rev. N 1).
2a.3. Premises in which work with the drug is carried out must be equipped with general supply and exhaust ventilation. The analysis of the drug should be carried out in a laboratory fume hood.
2. ACCEPTANCE RULES
2.1. Acceptance rules - according to GOST 3885-73.
2.2. The mass fraction of arsenic according to subparagraph 8 of the table is determined only at the request of consumers.
3. METHODS OF ANALYSIS
3.1a. General instructions for the analysis - in accordance with GOST 27025-86.
When weighing, general-purpose laboratory scales of the VLR-200 g and VLKT-500 g-M or VLE-200 g types are used.
It is allowed to use other measuring instruments with metrological characteristics and equipment with technical characteristics not worse, as well as reagents in quality not lower than those specified in this standard.
3.1. Samples are taken according to GOST 3885-73. The mass of the average sample must be at least 265 g.
3.1a; 3.1. (Changed edition, Rev. N 2).
3.2. Determination of the mass fraction of metaphosphoric acid
3.2.1. Reagents, solutions, apparatus and utensils:
bromcresol green (indicator) according to TU 6-09-07-1579-87, solution with a mass fraction of 0.2%; prepared as follows: 0.200 g of bromcresol green is dissolved in a mixture consisting of 6 ml of sodium hydroxide solution with a concentration of 0.1 mol / dm and 5 ml of alcohol. The volume of the solution is adjusted with water to 100 cm 3 and mixed;
buffer mixture with pH 4.6; prepared as follows: 100 ml of phosphate-citrate buffer solution is placed in a conical flask and 0.5 ml of bromcresol green solution is added. To prevent the development of bacteria, the buffer mixture is sterilized by heating to 60-70 ° C, 0.01 g of thymol is added and mixed. The solution is stored in a flask closed with a rubber stopper in a dark place;
distilled water according to GOST 6709-72;
sodium hydroxide according to GOST 4328-77, concentration solutions (NaOH)=0.1 mol/dm (0.1 N) and 0.2 mol/dm (0.2 N); prepared according to GOST 25794.1-83;
thymol according to TU 6-09-3736-79, part;
phosphate-citrate buffer solution pH 4.6; prepared according to GOST 4919.2-77;
pipettes 4(5)-2-1(2) and 6(7)-2-5(10) according to GOST 29227-91;
cylinder 1(3)-100 according to GOST 1770-
3.2.2. Conducting an analysis
About 0.5000 g of the drug is placed in a conical flask, 70 cm3 of water are added, heated to a boil and boiled for 20-30 minutes, adding water during the boiling process to the original volume. 0.5 ml of bromcresol green solution is added to the cooled solution and titrated from a burette with a sodium hydroxide solution of a concentration of 0.2 mol/dm3 until the color of the analyzed solution changes from yellow to green and then to green-blue, coinciding with the color of the buffer mixture used for comparisons.
3.2.3. Results processing
The mass fraction of metaphosphoric acid () as a percentage is calculated by the formula
,
where is the volume of a sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, used for titration, cm;
0.01599 is the mass of metaphosphoric acid corresponding to 1 cm3 of sodium hydroxide solution, concentration exactly 0.2 mol/dm, g.
Permissible absolute total error of the analysis result ± 0.6% at a confidence level = 0.95
3.2.1-3.2.3. (Changed edition, Rev. N 1, 2).
3.3. Determination of the mass fraction of the sodium salt of metaphosphoric acid
3.3.1. Reagents, solutions, apparatus and utensils:
bromcresol green (indicator) according to TU 6-09-07-1579-87, solution with a mass fraction of 0.2%; prepared according to clause 3.2.1;
buffer mixture with pH 4.6; prepared according to clause 3.2.1;
distilled water, not containing carbon dioxide; prepared according to GOST 4517-87;
2,4-dinitrophenol (-dinitrophenol), solution with a mass fraction of 0.1%; prepared according to GOST 4919.1-77;
nitric acid according to GOST 4461-77;
hydrochloric acid according to GOST 3118-77, concentration solution (HCl)=1 mol/dm (1 N); prepared according to GOST 25794.1-83;
methyl red (indicator) according to TU 6-09-5169-84;
sodium hydroxide according to GOST 4328-77, a solution with a mass fraction of 30% and a solution of concentration (NaOH) - 0.2 mol / dm (0.2 N); prepared according to GOST 25794.1-83;
mixed indicator, alcohol solution; prepare as follows: 0.100 g of methyl red and 0.600 g of phenolphthalein are placed in a conical flask and dissolved in 100 ml of alcohol;
rectified technical ethyl alcohol in accordance with GOST 18300-87, premium;
phenolphthalein (indicator) according to TU 6-09-5360-87;
burette 1-2-50-0.1 according to GOST 29251-91;
flask Kn-2-250-34 THS according to GOST 25336-82;
flask 2-250-2 according to GOST 1770-74;
pipettes 2(3)-2-25 and 6(7)-2-10 according to GOST 29227-91;
cup H-1-400 THS according to GOST 25336-82;
cylinder 1(3)-100 according to GOST 1770-74.
3.3.2. Conducting an analysis
About 3.0000 g of the drug is placed in a beaker, 125 ml of water and 10 ml of nitric acid are added. The solution is heated to boiling and boiled for 30 minutes, topping it up with water during boiling to the original volume. After cooling, 1 cm3 of a solution of 2,4-dinitrophenol and a solution of sodium hydroxide with a mass fraction of 30% are added to the solution until a slightly yellow color appears and cooled again. A solution of hydrochloric acid is added to the cooled solution until the color disappears, and then another 1-2 cm of acid. The contents of the beaker are transferred to a volumetric flask, the volume of the solution is adjusted to the mark with water and mixed.
Place 25 ml of the prepared solution into two conical flasks with a pipette with a capacity of 25 ml, add 50 ml of water to each flask and mix.
The solution in one flask is titrated from a burette with a solution of sodium hydroxide at a concentration of 0.2 mol/dm in the presence of 0.2 ml of a solution of bromocresol green until the color matches the color of the buffer mixture.
The solution in the second flask is titrated from a burette with a solution of sodium hydroxide with a concentration of 0.2 mol / dm in the presence of a mixed indicator until the crimson color of the solution changes through yellow and orange to red.
nuyu.
3.3.3. Results processing
The mass fraction of the sodium salt of metaphosphoric acid () as a percentage is calculated by the formula
where is the volume of a solution of sodium hydroxide with a concentration of exactly 0.2 mol / dm, used for titration in determining the mass fraction of metaphosphoric acid according to clause 3.2.3, cm;
- the volume of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, used for titration with a mixed indicator, cm;
- the volume of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, used for titration with the indicator bromcresol green, cm;
- the weight of the sample of the drug when determining the mass fraction of metaphosphoric acid according to clause 3.2.3, g;
- weight of sample of the drug, g;
0.02039 - the mass of the sodium salt of metaphosphoric acid, corresponding to 1 cm 3 of sodium hydroxide solution with a concentration of exactly 0.2 mol / dm, g.
The result of the analysis is taken as the arithmetic mean of the results of two parallel determinations, the absolute discrepancy between which does not exceed the allowable discrepancy equal to 1%.
Permissible absolute total error of the analysis result ± 0.7% at a confidence level
=0,95.
3.4. The determination of the mass fraction of sulfates is carried out according to GOST 10671.5-74 by the visual nephelometric method (method 1). At the same time, 50.00 g of the drug is placed in a glass with a capacity of 400 cm 3 and dissolved when heated in 200 cm 3 of water. The solution is boiled for 2 hours, topping it up with water during boiling to the original volume. After cooling, the solution is transferred into a volumetric flask with a capacity of 250 ml, the volume of the solution is adjusted to the mark with water and mixed - solution A.
Solution A is kept for the determination of nitrates according to paragraph 3.5, chlorides according to paragraph 3.6, iron according to paragraph 3.7, heavy metals according to paragraph 3.8, arsenic according to paragraph 3.9.
10 cm 3 of solution A (corresponding to 2.00 g of the preparation) are taken with a pipette, filtered, if it is cloudy, through an ash-free blue ribbon filter, previously washed three times with hot water, placed in a beaker or conical flask and the volume of the solution is adjusted with water to 26 cm. Further, the determination is carried out according to GOST 10671.5-74 without adding a solution of hydrochloric acid, using an alcohol solution of barium chloride instead of water. A solution of barium chloride is prepared as follows: 5.00 g of barium chloride is dissolved in a mixture consisting of 66.5 cm3 of water and 28.5 cm3 of premium ethyl alcohol (GOST 18300-87).
The drug is considered to comply with the requirements of this standard if the observed opalescence of the analyzed solution is not more intense than the opalescence of a solution containing in the same volume: 0.02 mg SO, 1 ml hydrochloric acid solution with a mass fraction of 10%, 3 ml starch solution and 3 ml alcohol solution chloride b
aria.
3.3.1-3.3.3; 3.4. (Changed edition, Rev. N 1, 2).
3.5. The determination of the mass fraction of nitrates is carried out according to GOST 10671.2-74 using indigo carmine. At the same time, 10 cm 3 of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a conical flask with a capacity of 50-100 cm 3, and then the determination is carried out according to GOST 10671.2-74.
The drug is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not weaker than the color of a solution containing in the same volume: 0.01 mg of NO, 1 ml of sodium chloride solution, 1 ml of indigo carmine solution and 12 ml of concentrated sulfuric acid.
(Changed edition, Rev. N 2).
3.6. Determination of the mass fraction of chlorides is carried out according to GOST 10671.7-74 visual-nephelometric (method 2) method. At the same time, 20 cm3 of solution A (corresponding to 4 g of the drug) prepared according to clause 3.4 is taken with a pipette, filtered, if it is cloudy, through an ash-free "blue tape" filter, previously washed with a hot solution of nitric acid with a mass fraction of 1%, placed in a conical flask with a capacity of 100 cm3, the volume of the solution is adjusted to 30 cm3 with water, and then the determination is carried out to GOST 10671.7-74 without adding a solution of nitric acid.
The drug is considered to comply with the requirements of this standard if the opalescence of the analyzed solution is not more intense than the opalescence of a solution containing 0.040 mg CI, 2 ml of nitric acid solution and 1 ml of silver nitrate solution in the same volume.
3.7. The determination of the mass fraction of iron is carried out according to GOST 10555-75 by the sulfosalicylic method. At the same time, 2 cm3 of solution A (corresponding to 0.4 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a volumetric flask with a capacity of 50 cm3, the volume of the solution is adjusted to 21 cm3 with water, and then the determination is carried out according to GOST 10555-75 without adding hydrochloric acid acids.
The preparation is considered to comply with the requirements of this standard if the mass of iron does not exceed 0.008 mg.
It is allowed to carry out the determination visually.
In case of disagreement in the assessment of the mass fraction of iron, the analysis is carried out photometrically.
3.6; 3.7. (Changed edition, Rev. N 1, 2).
3.8. The determination of heavy metals is carried out according to GOST 17319-76 by the hydrogen sulfide method. At the same time, 10 ml of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into a 100 ml conical flask (with ground or rubber stopper), neutralized with an ammonia solution with a mass fraction of 10% according to universal indicator paper to pH 7 and bring the volume of the solution with water to 30 cm. Further, the determination is carried out according to GOST 17319-76.
The preparation is considered to comply with the requirements of this standard if the observed color of the analyzed solution is not more intense than the color of the solution containing in the same volume; 0.01 mg Pb, 1 ml acetic acid, 1 ml ammonium acetate solution and 10 ml hydrogen sulfide water.
(Changed edition, Rev. N 2).
3.9. The determination of the mass fraction of arsenic is carried out according to GOST 10485-75 by the visual method using bromine-mercury paper in a sulfuric acid medium. At the same time, 10 cm 3 of solution A (corresponding to 2 g of the preparation) prepared according to clause 3.4 is placed with a pipette into the flask of the device for determining arsenic and 20 cm 3 of water are added. Further, the determination is carried out according to GOST 10485-75.
The drug is considered to comply with the requirements of this standard if the observed color of bromine-mercury paper from the analyzed solution is not more intense than the color of bromine-mercury paper from a solution prepared simultaneously with the analyzed one and containing in the same volume: 0.004 mg As, 20 ml of sulfuric acid solution, 0 .5 ml of a solution of stannous chloride and 5 g of zinc.
(Changed edition, Rev. N 1, 2).
3.10. Potassium permanganate reducing agent test
3.10.1. Reagents, solutions, equipment:
distilled water according to GOST 6709-72, distilled in the presence of potassium permanganate;
potassium permanganate according to GOST 20490-75, a solution of concentration (KMnO) = 0.01 mol / dm (0.01 N.) is prepared according to GOST 25794.2-83, freshly prepared;
flask Kn-2-100-22 THS or Kn-1-100-14/23 THS according to GOST 25336-82;
pipettes 6(7)-2-25 and 4(5)-2-1(2) or 1-2-1 according to GOST 29227-91;
cylinder 1(3)-25(50) according to GOST 1770-74.
3.10.2. Conducting an analysis
10.00 g of the drug is placed in a conical flask and dissolved in 20 cm3 of water while heating. Then 1 cm3 of a solution of potassium permanganate is added, the solution is heated to a boil and kept in a water bath for 10 minutes.
The preparation is considered to comply with the requirements of this International Standard if the observed pink color of the analyzed solution does not disappear within 5 minutes.
3.10.1; 3.10.2. (Changed edition, Rev. N 2).
4. PACKAGING, LABELING, TRANSPORT AND STORAGE
4.1. The drug is packaged and labeled in accordance with GOST 3885-73.
Types and types of containers: 2-1, 2-4, 2-9.
Packing groups: V and VI.
(Changed edition, Rev. N 1).
4.2. The drug is transported by all means of transport in accordance with the rules for the carriage of goods in force on this type of transport.
4.3. The drug is stored in the manufacturer's packaging in covered warehouses.
5. MANUFACTURER WARRANTY
5.1. The manufacturer guarantees the compliance of metaphosphoric acid with the requirements of this standard, subject to the conditions of transportation and storage.
5.2. Guaranteed shelf life - 1 year from the date of manufacture.
5. (Changed edition, Rev. N 1).
6. (Deleted, Rev. N 1).