FEDERAL AGENCY
ON TECHNICAL REGULATION AND METROLOGY
NATIONAL
STANDARD
RUSSIAN
FEDERATION
Specifications
Official publication
Form standards
GOST R 57568-2017
Preface
1 DEVELOPED by the Federal State Budgetary Institution of Science "Institute of Water Problems Russian Academy Sciences (IVP RAS)"
2 INTRODUCED by the Technical Committee for Standardization TC 060 “Chemistry”
3 APPROVED AND ENTERED INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated August 1, 2017 No. 777-st
4 INTRODUCED 8FIRST
The rules for applying this standard are established in Article 26 of the Federal Law of June 29, 2015 MI62-FZ “On standardization in Russian Federation" Information about changes to this standard is published in the annual (as of January 1 of the current year) information index “National Standards”, and the official text of changes and amendments is published in the monthly information index “National Standards”. In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the monthly information index “National Standards”. Relevant information, notifications 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 ()
© Stamdartinform. 2017
This standard cannot be fully or partially reproduced, replicated or distributed as an official publication without permission from the Federal Agency for Technical Regulation and Metrology
GOST R 57568-2017
1 area of use............................................... ........................................................ ...................................1
3 Technical requirements................................................... ........................................................ ........................2
4 Safety requirements................................................... ........................................................ ...........................3
5 Methods of analysis................................................... ........................................................ ...........................................4
5.1 Sampling................................................................... ........................................................ ............................................4
5.2 General instructions for conducting analysis.................................................... ...............................................4
5.3 Determining the appearance of the product.................................................... ........................................................ .4
5.4 Determination of light transmittance............................................................. ..................................5
5.5 Determination of mass concentration of active chlorine.................................................... ........................5
5.6 Determination of the mass concentration of alkaline components in terms of NaOH....................................7
5.7 Determination of the mass concentration of iron by the photometric method....................................................9
5.8 Determination of the content of chlorites, chlorates and bromates.................................................... ...................10
5.9 Determination of element content (Fe. As. Cd. Cr. Hg. Ni. Pb. Sb. Se) by method
atomic emission spectrometry with inductively coupled plasma.................................................... 13
6 Transportation, storage.................................................................... ........................................................ ...................16
6.1 Delivery and transportation of the product.................................................... ............................................16
6.2 Warehousing and storage.................................................... ........................................................ ................16
7 Manufacturer's warranty................................................................... ........................................................ ....................... 17
Appendix A (informative) General data on an aqueous solution of sodium hypochlorite....................................18
Bibliography................................................. ........................................................ .............................................20
GOST R 57568-2017
Introduction
This standard has been developed to ensure the production of competitive and safe products (aqueous solution of sodium hypochlorite), especially with regard to restrictions on the content of highly toxic impurities of elements of hazard classes 1 and 2. The introduction of the standard will ensure the safety of using an aqueous solution of sodium hypochlorite in drinking water supply and other high-tech industries.
This standard presents a set of analytical methods for quality control of an aqueous solution of sodium hypochlorite, indicating their metrological characteristics.
GOST R 57568-2017
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
SODIUM HYPOCHLORITE SOLUTION, AQUEOUS
Specifications
Sodiumhypochlorite aqueous solution. Specifications
Date of introduction - 2018-02-01
1 area of use
This standard applies to an aqueous solution of sodium hypochlorite (sodium hypochlorite), obtained by electrolysis of a solution of sodium chloride in a membrane electrolytic cell (Appendix A).
An aqueous solution of sodium hypochlorite is intended for use in local or centralized drinking water supply systems, for disinfection of swimming pool water. Chemical name: sodium hypochlorite.
Chemical formula: NaOCI.
Relative molecular mass (based on international atomic masses 2016): 74.44.
2 Normative references
8 of this standard are used Normative references to the following standards:
GOST 83 Reagents. Sodium carbonate. Specifications
GOST 1770 Laboratory glassware. Cylinders. beakers, flasks, test tubes. Are common technical specifications
GOST 3118 Reagents. Hydrochloric acid. Specifications
GOST 4204 Reagents. Sulfuric acid. Specifications
GOST 4220 Reagents. Potassium dichromate. Specifications
GOST 4232 Reagents. Potassium iodide. Specifications
GOST 4457 Reagents. Potassium is bromate-acidic. Specifications
GOST 4517 Reagents. Methods for preparing auxiliary reagents and solutions used in analysis
GOST 4919.1 Reagents and highly pure substances. Methods for preparing solutions of indicators GOST 10157 Argon gaseous and liquid. Specifications
GOST 10555 Reagents and highly pure substances. Colorimetric methods for determining the content of iron impurities
GOST 10929 Reagents. Hydrogen peroxide. Technical specifications GOST 11086-76 Sodium hypochlorite. Technical specifications GOST 11125 Nitric acid of special purity. Technical specifications GOST 12257 Technical sodium chlorate. Technical specifications GOST 17299 Technical ethyl alcohol. Technical specifications GOST 19433 Dangerous goods. Classification and labeling
GOST 25336 Laboratory glassware and equipment. Types, main parameters and sizes
Official publication
GOST R 57568-2017
GOST 25794.1 Reagents. Methods for preparing titrated solutions for acid-base titrations
GOST 28311 Medical laboratory dispensers. General technical requirements and test methods
GOST 29169 Laboratory glassware. Pillettes with one mark GOST 29224 Laboratory glassware. Laboratory liquid glass thermometers. Principles of design, construction and application
GOST 29227 Laboratory glassware. Graduated pipettes. Part 1. General requirements GOST 29251 Laboratory glassware. Burettes. Part 1. General requirements GOST 31340 Warning labeling of chemical products. General requirements GOST R 53228 Non-automatic scales. Part 1. Metrological and technical requirements. Tests.
GOST R 52501 Water for laboratory analysis. Specifications
GOST R 55878-2013 Rectified technical hydrolysis ethyl alcohol. Specifications
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 Metrology on the Internet or using the annual information index “National Standards) *, which was published as of January 1 of the current year , and according to the releases of the monthly information index “National Standards” for the current year. If an undated reference standard is replaced, it is recommended that the current version of that standard be used, taking into account any changes made to that version. If a dated reference standard is replaced, it is recommended to use the version of that standard with the year of approval (adoption) indicated above. If, after the approval of this standard, a change is made to the referenced standard to which a dated reference is made that affects the provision to which the reference is given, then it is recommended that this provision be applied without taking into account this change. If the reference standard is canceled without replacement, then the provision to which a reference is made to it is recommended to be applied in the part that does not affect this reference.
3 Technical requirements
3.1 Sodium hypochlorite solution must be manufactured in accordance with the requirements of this standard.
3.2 Specifications
3.2.1 In terms of physical and chemical parameters, the aqueous solution of sodium hypochlorite must meet the requirements and standards specified in Table 1.
Table 1 - Physico-chemical parameters of the composition of an aqueous solution of sodium hypochlorite
|
Indicator name |
Indicator value |
|
|
Appearance |
Yellow to greenish-yellow liquid |
|
|
Fresh transmission coefficient. %. no less | ||
|
Mass concentration of active chlorine, t/dm 3, not less | ||
|
Mass concentration of alkaline components in terms of NaOH. g/dm 3. within | ||
|
Mass concentration of iron (Fe). mg/dm 3, no more | ||
|
Mass fraction of chlorate ions (CLi). % ("). no more | ||
|
Mass concentration of chlorite ions (CLi). t/dm 3, no more | ||
|
Mass concentration of bromate compounds (BrOf). mg/dm3. no more | ||
|
Mass concentration of arsenic (As), mg/dm3. no more | ||
|
Mass concentration of cadmium (Cd). mg/dm 3, no more |
GOST R 57568-2017
End of table 1
|
Indicator name |
Value indicators |
|
|
Mass concentration of chromium (Cr). mg/dm3. no more | ||
|
Mass concentration of mercury (Hd). mg/dm3. no more | ||
|
Mass concentration of nickel (Ni). mg/dm3. no more | ||
|
Mass concentration of lead (Pb). mg/dm3. no more | ||
|
Mass concentration of antimony (Sb). mg/dm 3, without pain | ||
|
Mass concentration of selenium (Se). mg/dm3. no more | ||
|
Note - Quality indicators from paragraphs 1 to 5 are determined from each batch. Quality indicators from clause 6 to clause 16 are determined periodically, as well as at the request of the customer. (*) - mass fraction of relatively active chlorine. Loss of active chlorine is allowed no more than 2% per day of the initial content. as well as an increase in the content of chlorate ions and bromagine ions. chlorite ions no more than 10% of the original content (provided the product is stored at a temperature not exceeding 20 s C). |
||
3.2.2 The density of a commercial solution with a mass content of active chlorine of 170 g/dm 3 at 20 °C is 1240 g/dm 3.
3.3 Requirements for commercial product purity
3.3.1 This standard defines the minimum requirements for the purity of an aqueous solution of sodium hypochlorite used for the purposes set out in Section 1 “Scope”. Limits are for impurities typically present in the product. If manufacturing processes or the original composition of raw materials result in the appearance of other impurities in significant quantities, this should be reported to the end user.
3.4 Product labeling
3.4.1 Product labeling must contain the following:
Name “aqueous solution of sodium hypochlorite”, trade name:
Net weight;
Name and address of supplier and/or manufacturer:
Indication “this product complies with GOST R...”;
Batch number;
Date of manufacture;
Shelf life.
3.4.2 Warning markings must contain warning signs according to the types of hazard in accordance with GOST 31340 (hazard class 1A - N314, hazard class 1 - N318, hazard class 2 - N411).
4 Safety requirements
4.1 Rules for safe handling and use
The manufacturer or supplier must provide consumers and other interested parties with updated guidance materials on safety measures, standards and regulations at the stages of handling and use of the finished sodium hypochlorite product solution (Appendix B).
GOST R 57568-2017
4.2 Fire precautions
4.2.1 An aqueous solution of sodium hypochlorite is non-flammable and explosion-proof, however, upon contact with organic flammable substances (sawdust, rags, etc.) during the drying process, it can cause a fire.
4.2.2 In a fire zone where an aqueous solution of sodium hypochlorite is present, it is recommended to extinguish it with sprayed water, sand or carbon dioxide fire extinguishers. It is not recommended to use powder extinguishing agents, which at high temperatures intensively destroy polymer construction materials.
4.2.3 In the event of a fire threat, containers with an aqueous solution of sodium hypochlorite should be cooled with water.
4.3 Rules of conduct in emergency situations
Sodium hypochlorite is an oxidizing agent that causes damage to the skin and mucous membranes.
In case of emergency, it is necessary to carry out first aid measures for victims (Appendix B) and seek medical help.
4.4 Procedure for liquidating emergencies and emergencies
4.4.1 In the event of a leak, release or spill of sodium hypochlorite, the incident should be reported to the territorial supervisory authority. It is necessary to eliminate the source of the emergency situation taking precautions. Spills must be fenced off with an earth bank, covered with fishing line or other inert material, which is then collected and taken away for disposal.
4.4.2 The spill area must be washed with plenty of water. Do not allow the product to enter water bodies or sewers. The resulting diluted sodium hypochlorite solution should be neutralized using solutions of sodium sulfite, sodium hydrosulfite, hydrogen peroxide or sodium thiosulfate.
5 Methods of analysis 1 *)
5.1 Sampling
5.1.1 Point samples from the tank and storage facility are taken from the upper, middle and lower levels with a sampler made of vinyl plastic, or polyethylene, or titanium. Spot samples from containers, barrels, bottles are taken from the middle level with a sampler made of vinyl plastic, polyethylene, polypropylene or titanium.
The manufacturer is allowed to take samples from pipelines transporting the product when shipping products by taking spot samples at the beginning, middle and end of loading.
Before taking a sample from a tank, storage facility, container at a temperature below O * C, it is necessary to mix the product with nitrogen or air. Before sampling from barrels and bottles, the contents are also mixed.
The volume of a spot sample is at least 100 cm3.
5.1.2 Point samples are combined, mixed and an average sample with a volume of at least 250 cm3 is taken. The average sample is placed in a dark glass (plastic) jar with a ground-in stopper or a tightly screwed lid. A label is pasted (attached) to the jar indicating the name of the product, the inscription “Corrosive Substance”, the batch of goods, the place and date of sampling, and the name of the sampler.
5.2 General instructions for analysis
Rounding of analysis results to the sign indicated in the table of technical requirements.
5.3 Determining the appearance of the product
The appearance of the product is determined visually in a P1-30-250 XC test tube in accordance with GOST 25336. Test results are interpreted in accordance with GOST 27025.
1 * It is allowed to use standardized (certified) methods of analysis other than those indicated,
with metrological characteristics no worse than those given in this standard.
GOST R 57568-2017
5.4 Determination of light transmittance
5.4.1 Hardware
Any brand of photocolorimeter or spectrophotometer that measures absorbance at X in the range from 630 to 690 nm.
Filter funnel VF-1.2 according to GOST 2S336. filter class POR 16.
The cuvette is glass with a light-absorbing layer thickness of 20 mm.
Conical flask Kn-1.2-100 according to GOST 25336.
5.4.2 Conducting analysis
The light transmission coefficient of the analyzed product is determined relative to the control solution. The determination is carried out using a cuvette with an absorbing layer thickness of 20 mm at a wavelength k - 650.
8, the analyzed product filtered through a filter funnel is used as a control solution.
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 repeatability limit in accordance with Table 2, with a confidence probability of P = 0.95.
Table 2 - Metrological characteristics of the method for determining the light transmission coefficient
5.5 Determination of mass concentration of active chlorine
5.5.1 Equipment, reagents, solutions
Burette I(3)-1*50 or I(3)-1-25 with a division value of 0.05 according to GOST 29251.
Conical flasks Kn-1.2*250. 500 according to GOST 25336.
Volumetric flask 1.2-250.1000 according to GOST 1770.
Conical flask type Kn-1.2-500 according to GOST 25336.
Pipettes 2-1-10 according to GOST 29169.
Glass glass V.N-1.2-50 according to GOST 25336.
Measuring cylinder 1.3-25 according to GOST 1770.
Thermometer with a measurement range from 0 to 100 *C and a determination accuracy of at least 12 *C.
Sulfuric acid, analytical grade. solution of molar concentration (1/2 H 2 S0 4) = 1 mol/dm 3. prepared according to GOST 25794.1. the solution is good for 6 months from the date of preparation.
Soluble starch, solution with a mass fraction of 1%. prepared according to GOST 4517.
Sodium disulfate-acid (sodium thiosulfate), solution of molar concentration (Na 2 S 2 0 3 5H 2 0) = 0.1 mol/dm 3, is prepared from a standard titer in accordance with the attached instructions.
Potassium dichromate, chemically pure. according to GOST 4220. solution molar concentration (V 8 K 2 Cr 2 0 7) - 0.1 mol/dm 3. prepare as follows:
On a scale, exactly (4.903 ± 0.001) g of 1^Cr 20 7 are weighed in a glass beaker. The sample is quantitatively transferred to a 1000 cm 3 volumetric flask, dissolved and brought to the mark with water for laboratory analysis of purity level 2. The prepared solution is stored in a dark glass container at a temperature of 2-8 * C. The solution is good for 3 months. It is allowed to prepare a solution from the standard titer in accordance with the instructions attached to the standard titer.
Sulfuric acid, analytical grade. according to GOST 4204. solution with a mass fraction of 20%.
Potassium iodide, analytical grade. lo GOST 4232, solution with a mass fraction of 10% (solution A), prepared according to GOST 4517.
Potassium iodide, analytical grade. according to GOST 4232. solution with a mass fraction of 30% (solution B), specified in GOST 4517.
GOST R 57568-2017
5.5.2 Establishing the correction factor for a sodium thiosulfate solution with a concentration of 0.1 mol/dm 3 (method 1)
In a dry conical flask 250 cm 3 with a ground stopper, weigh 0.0500-0.1000 g of potassium dichromate, dried to constant weight at 150 * C. The mass is recorded with an accuracy of 0.0001 g.
50 cm 3 of water for laboratory analysis is added to the sample, stirring in a circular motion until the sample is completely dissolved. Add with a pipette 10 cm 3 of a solution of potassium iodide with a mass concentration of 10% and 20 cm 3 of sulfuric acid with a mass concentration of 20%. Stir, close the flask with a lid and leave in a dark place for 10 minutes. Titrate with a solution of sodium thiosulfate with a concentration of 0.1 mol/dm 3 until the color changes from brown to yellow, then add 2 cm 3 of starch and continue titration with thorough stirring until the color of the solution changes from blue to light green. Determine the volume of sodium thiosulfate used for titration. Titration is repeated 3 times.
The correction factor (K) is calculated using formula (1)
t, 1000 V- 0.1 49.3‘
where V is the volume of sodium thiosulfate solution consumed for titration, cm 3:
49.3 - molar mass equivalent of potassium dichromate, g/mol: t 1 - mass of a sample of potassium dichromate, g.
5.5.3 Establishing the correction factor for a sodium thiosulfate solution with a concentration of 0.1 mol/dm 3 (method 2)
To set the correction factor, use 0.1 mol/dm 3 solution of potassium dichromate. To do this, 10 cm 3 of potassium dichromate solution are placed into three conical flasks with a capacity of 500 cm 3 using a pipette. 10 cm 3 potassium iodide (solution B). 20 cm 3 sulfuric acid solution (20%). Immediately close with a stopper, mix and keep in a dark place for 10 minutes. After this, add 200 cm 3 of water for laboratory analysis (second degree of purity) and titrate the released iodine with a solution of sodium thiosulfate until the color turns light yellow. Then add 2 cm 3 of starch solution and continue titrating until the blue color disappears.
The correction factor (K) is determined by formula (2)
V;
where V is the volume of 0.1 mol/dm 3 solution of potassium dichromate taken for titration, cm 3 ;
V is the volume of 0.1 mol/dm 3 sodium thiosulfate solution consumed for titration, cm 3.
The correction factor is determined at the temperature of the environment and working solutions (20 ± 2) * C and is calculated with an accuracy of 4 decimal places for each of the three set volumes of potassium dichromate.
The discrepancy between the maximum and minimum volumes used for titration of three parallel determinations should not exceed ± 0.05 cm 3 . The arithmetic mean is taken from the calculated coefficient values. The correction factor value should be equal to (1.00 ±0.03).
5.5.4 Conducting analysis
10 cm 3 of an aqueous solution of sodium hypochlorite having a temperature of (20 ± 2) * C is pipetted into a 250 cm 3 volumetric flask, the volume of the solution is adjusted to the mark with water and mixed (diluted sodium hypochlorite solution).
10 cm 3 of the resulting dilute solution of sodium hypochlorite is transferred with a pipette into a conical flask, 10 cm 3 of potassium iodide solution is added, mixed, 20 cm 3 of sulfuric acid solution is added, mixed again, the flask is capped and placed in a dark place.
After 5 minutes, titrate the released iodine with a solution of sodium sulfate until the solution turns light yellow, then add 2-3 cm 3 of starch solution and continue titration until the solution becomes discolored.
GOST R 57568-2017
5.5.5 Processing results
Mass concentration of active chlorine X, g/dm 3, is calculated using formula (3)
U K 0.003545 250 1000 10-10
where V is the volume of sodium sulfate solution with a concentration of 0.1 mol/dm e. spent on titration, cm 3:
K is the correction factor for a solution of sodium disulfide with a concentration of 0.1 mol/dm 3: 0.003545 is the mass of active chlorine corresponding to 1 cm 3 of a solution of sodium disulfate with a concentration of exactly 0.1 mol/dm 3, g.
The arithmetic mean of the results of two parallel determinations is taken as the result of the analysis. the absolute discrepancy between them does not exceed the repeatability limit in accordance with Table 3, with a confidence probability of P = 0.95.
Table 3 - Metrological characteristics of the method for determining active chlorine
5.6 Determination of mass concentration of alkaline components in terms of NaOH
5.6.1 Equipment, reagents, solutions Burette M(3>-1-50 or according to GOST 29251.
Conical flask Kn-1.2-250 according to GOST 25336.
Volumetric flask 1.2-250.500.1000 according to GOST 1770.
Pipette 2-1-50 according to GOST 29169.
Pipettes 2-1-2.5.10 according to GOST 29169.
Measured cylinder 1.3-25 according to GOST 1770.
Measuring cylinder 1.3-50 according to GOST 1770.
Drying cabinet of any type.
pH meter of any design with a measurement range from 1 to 13 units. pH and determination accuracy of at least ± 0.1 units. pH.
Non-automatic scales in accordance with GOST R 53228 of at least class II accuracy with a division value of no more than 0.001 g.
Thermometer with a measurement range from 0 to 100 °C and a determination accuracy of at least ± 2 *C. Desiccator according to GOST 25336.
Water for laboratory analysis, purity level 2 according to GOST R 52501.
Hydrogen peroxide, analytical grade. according to GOST 10929. solution with a mass fraction of 10%. neutralized with sodium hydroxide solution 0.1 mol/dm 3 to pH (7.1-7.3).
Sodium hydroxide, solution of molar concentration with (NaOH) = 0.1 mol/dm 3.
Hydrochloric acid, solution of molar concentration with (HCI) = 0.1 mol/dm 3.
Technical ethyl alcohol according to GOST 17299 grade A or rectified technical alcohol according to GOST 18300 grade “Extra”.
Phenolphthalein, alcohol solution with a mass fraction of 1%. prepared according to GOST 4919.1. Sodium carbonate chemically pure according to GOST 83.
Mixed acid-base indicator (methyl red and methylene blue) according to GOST 4919.1.
GOST R 57568-2017
5.6.2 Preparation of a solution of sodium carbonate of molar concentration C(Na 2 CO))
0.1 mol/dm 3
Add (5.200 ± 0.001) g of sodium carbonate, previously dried in an oven at a temperature of (250 110) * C for 4 hours, into a volumetric flask with a capacity of 500 cm 3. A small amount of water for laboratory analysis is added to the flask until the salt is completely dissolved, bring volume of the solution to the mark with water for laboratory analysis and mix.
Shelf life of the solution in a container made of polymer material in the refrigerator at a temperature of (4-8) °C - no more than one month.
5.6.3 Establishing the correction factor for hydrochloric acid with a concentration of 0.1 mol/dm 3 for sodium carbonate
To set the correction factor, use 0.1 mol/dm 3 sodium carbonate solution. To do this, pipet 5.0 cm 3 of sodium carbonate solution into three conical flasks with a capacity of 250 cm 3 and add (40 ± 5) cm 3 of water for laboratory analysis. Titrate with a solution of hydrochloric acid of a molar concentration of 0.1 mol/dm 3, respectively, fixing the end point of titration potentiometrically at a pH value (4.5 ± 0.1) or visually with a mixture of indicators until the green color of the solution changes to red-violet.
The correction factor is determined by formula (4)
™"Uso, 1000 53.0 V HC | У №п6ы ^)С1
where m is the mass of sodium carbonate taken to prepare the solution (5.2 g to prepare 0.1 mol/dm3). G.
^ per g co 3 - volume of sodium carbonate solution taken for titration, cm 3;
1000 - conversion factor;
With ns, is the specified concentration of hydrochloric acid solution (0.1 mol/dm 3);
53.0 - molar mass of sodium carbonate equivalent, g/mop;
U ns, is the volume of hydrochloric acid solution consumed for the titration of sodium carbonate, cm 3;
^"flask - the volume of the flask taken to prepare a solution of sodium carbonate, cm 3.
The correction factor is determined at the temperature of the environment and working solutions (20 ± 2) in C and is calculated with an accuracy of 4 decimal places for each of the three set volumes of sodium carbonate.
The discrepancy between the maximum and minimum volumes used for titration of three parallel determinations should not exceed ± 0.05 cm3. The arithmetic mean is taken from the calculated coefficient values. The correction factor value should be equal to (1.00±0.03).
The correction factor is determined after preparing the solution and at least once a month if it is stored. If the correction factor is outside the specified limits or sediment or flakes appear in the solution during storage, the solution is replaced with a freshly prepared one.
5.6.4 Conducting analysis
50 cm 3 of a dilute solution of sodium hypochlorite, prepared according to 5.5.4, is pipetted into a conical flask and 20-25 cm 3 of hydrogen peroxide solution is carefully added in small portions, stirring carefully to avoid strong gas evolution. 2-3 minutes after the cessation of intense gas emission, 2-3 drops of phenolphthalein are added to the flask and its contents are titrated with a solution of hydrochloric acid until the solution becomes discolored, after which another 2-3 drops of phenolphthalein are added and if a pink color appears, titration is continued until the solution becomes discolored.
It is possible to carry out titration using the potentiometric method; in this case, titration is carried out to pH (8.3 ± 0.1).
5.6.5 Processing results
The mass concentration of alkaline components in terms of NaOH (Х d), g/dm 3, is calculated using formula (5)
V К 0.004 250 1000 10 50
where V is the volume of hydrochloric acid solution with a concentration of exactly 0.1 mol/dm3. spent on titration. cm 3.
GOST R 57568-2017
K is the correction factor for a solution of hydrochloric acid with a concentration of 0.1 mol/dm 3 ;
0.004 is the mass of sodium hydroxide corresponding to 1 cm 3 of hydrochloric acid solution with a concentration of exactly 0.1 mol/dm 3. G.
The arithmetic mean of the results of two parallel determinations is taken as the result of the analysis. the absolute discrepancy between which does not exceed the repeatability limit in accordance with Table 4. with a confidence probability of P = 0.95.
Table 4 - Metrological characteristics of the method for determining alkaline components" in terms of NaOH
5.7 Determination of mass concentration of iron by photometric method
5.7.1 Equipment, reagents
Conical flask type Kk 1.2-100 according to GOST 25336.
Volumetric flask 1.2-50.100 according to GOST 1770.
Pipettes 2-2-10.20.25 according to GOST 29169.
boda for laboratory analysis of purity level 2 according to GOST R 52501.
Measured cylinder 1.3-10 according to GOST 1770.
Hydrochloric acid, chemically pure. according to GOST 3118.
Electric stove of any brand.
A photocolorimeter or spectrophotometer of any brand that measures light absorption at X = 420 nm.
5.7.2 Conducting analysis
All actions are strictly carried out only in a fume hood!
20 cm 3 of a well-mixed sample of an aqueous hypochlorite solution, measured with a 20 cm 3 pipette, is transferred to a 100 cm 3 volumetric flask, adjusted to the mark with water for laboratory analysis of purity level 2 and mixed thoroughly.
25 cm 3 of the resulting solution is pipetted into a 100 cm 3 conical flask, 5.0 cm 3 of concentrated hydrochloric acid is carefully added and boiled at medium heat on an electric stove for 5 minutes.
Then the solution is cooled, transferred quantitatively into a 50 cm 3 volumetric flask, and then the analysis is carried out according to GOST 10555 using the sulfosalicylic method, without adding a solution of hydrochloric acid to the analyzed solution.
The construction of a calibration characteristic (GC) is carried out according to GOST 10555 at least once a year. GC stability control is carried out at least once every 3 months using three calibration solutions in accordance with GOST 10555, corresponding to the beginning, middle and end of the GC range. The result of stability control is considered satisfactory if the deviation from the specified concentrations of calibration solutions does not exceed 12%. otherwise, the GC construction is carried out again.
Mass concentration of iron X Ft, mg/dm 3, is calculated using formula (6)
v t 100 1000 X *“-JT25-
where m is the mass of iron found using the calibration curve, mg.
V is the volume of the initial sample of an aqueous solution of sodium hypochlorite taken for analysis, cm 3.
If the concentration exceeds the upper limit of the calibration curve, the original sample is diluted more times and the analysis is repeated.
The arithmetic mean of the results of two parallel determinations is taken as the result of the analysis. the absolute discrepancy between which does not exceed the repeatability limit in accordance with Table 5. with a confidence probability of P = 0.95.
GOST R 57568-2017
Table 5 - Metrological characteristics of the method for determining the mass concentration of iron by the photometric method
5.8 Determination of chlorites, chlorates and bromates
5.8.1 Essence of the method
Determination of the content of chlorites, chlorates and bromates is carried out by ion chromatography using a conductometric detector in a pre-diluted sample of sodium hypochlorite.
5.8.2 Equipment, reagents, solutions, glassware
Ion chromatograph consisting of the following parts:
Anionic suppressor of background electrical conductivity of the eluent (suppressor);
Conductometric detector;
Autosampler;
Chromatographic column for separation of anions:
Pre-column:
Low pulsation pump:
Loop dispenser with a volume of 20 or 100 µl.
Non-automatic scales in accordance with GOST R 53228 of at least class II accuracy with a division value of no more than 0.001 g.
Laboratory dispensers with variable volume (200-1000) µl and (1000-5000) µl according to GOST 28311.
Volumetric flask 1.2-50.100.200.500.1000-2 according to GOST 1770.
Pipettes 2-1.2-1.2.5.10 according to GOST 29169.
Chromatographic vials for aetosampler.
Disposable syringes 10 cm 3 and filter nozzles with a pore diameter of 0.45 microns - for filtering samples.
Personal computer with a program for collecting and processing chromatographic data.
Helium is compressed with a volume fraction of at least 99.5%.
Water for laboratory analysis, purity level 1 according to GOST R 52501.
Potassium bromate chemically pure according to GOST 4457 or imported with the content of the main substance not less
Sodium chlorate in accordance with GOST 12257 or imported with a content of the main substance of at least 99%.
Sodium chlorite with a basic substance content of at least 80%.
Eluent for ion chromatography - prepared in accordance with the passport for the chromatographic column used.
5.8.3 Preparation for analysis
Preparing the ion chromatograph and analytical column for operation and setting up the program for collecting and processing chromatographic data is carried out in accordance with the operating instructions.
5.8.4 Preparation of standard and working solutions
Preparation of a standard solution of chlorite ions with a concentration of 1000 mg/dm 3
In a volumetric flask with a capacity of 200 cm 3, dissolve 0.335 g of sodium chlorite in approximately 150 cm 3 of water for laboratory analysis and adjust the volume of the solution to the mark. The prepared solution is good for 2 months if stored in a dark glass container at a temperature of (2-8)°C.
Preparation of working solutions of chlorite ions with a concentration of 10 and 100 mg/dm 3
Working solutions with a concentration of chlorite ions of 100 and 10 mg/dm 3 are prepared in a 50 cm 3 volumetric flask by appropriate dilution with water for laboratory analysis of standard
GOST R 57568-2017
solution of chlorite ions 1000 mg/cm3. The prepared solutions are suitable for 1 week if stored in a dark glass container at a temperature of (2-8) *C.
Preparation of a standard solution of chlorate ions with a concentration of 1000 mg/dm 3
In a 200 cm3 volumetric flask, dissolve 0.255 g of sodium chlorate in approximately 150 cm3 of water for laboratory analysis and adjust the volume of the solution to the mark. The prepared solution is good for 3 months if stored in a dark glass container at a temperature of (2-8) *C.
Preparation of working solutions of chlorate ions with a concentration of 10 and 100 mg/dm 3
Working solutions with a concentration of chlorate ions of 100 and 10 mg/dm 3 are prepared in a 50 cm 3 volumetric flask by appropriate dilution with water for laboratory analysis of a standard solution of chlorate ions of 1000 mg/cm 3 . The prepared solutions are suitable for 1 month if stored in a dark glass container at a temperature of (2-8) *C.
Preparation of a standard solution of bromate ions with a concentration of 1000 mg/dm 3
In a 200 cm 3 volumetric flask, dissolve 0.261 g of potassium bromate in approximately 150 cm 3 of water for laboratory analysis and adjust the volume of the solution to the mark. The prepared solution is good for 3 months if stored in a dark glass container at a temperature of (2-8) *C.
Preparation of working solutions of bromate ions with a concentration of 10 and 100 mg/dm 3
Working solutions with a concentration of bromate ions of 100 and 10 mg/dm 3 are prepared in a 50 cm 3 volumetric flask by appropriate dilution with water for laboratory analysis of a solution of bromate ions of 1000 mg/cm 3 . The prepared solutions are suitable for 1 month if stored in a dark glass container at a temperature of (2-8) *C.
Note - Instead of prepared standard solutions of chlorite ions, bromate ions. Chlorate ions with a concentration of 1000 mg/dm 3 may use ready-made certified standard solutions.
5.8.5 Preparation of calibration solutions
Scale for calibration solutions of chlorite ions and bromate ions. Chlorate ions are prepared immediately before calibration by diluting the working solutions according to 5.8.4 with water for laboratory analysis in accordance with Table 6.
Table 6 - Preparation of calibration solutions for determining the content of chlorites, chlorates and bromates
|
Index |
Concentration of the calibration solution. mg/dm 3 |
Volume of working solutions used for preparation, cm 3 |
Volume of the volumetric flask used for preparation, cm 3 |
|
|
C * 10 mg/dm 3 |
C » 100 mg/dm 3 |
|||
|
Chlorate ion | ||||
|
Chlorite ion | ||||
|
Bromate ion | ||||
Note - Calibration is allowed using concentrations of solutions different from those indicated in the table, provided that the calibration solutions are within the calibration range.
GOST R 57568-2017
5.8.6 Chromatograph calibration
The chromatograph is calibrated in accordance with the operating instructions, measuring each calibration solution at least once. The chromatograph is calibrated at least once a year. and also in case of detection of instability of the calibration characteristic.
The stability of the calibration characteristic is monitored in one of the calibration solutions at least once every 3 months and when changing the column, reagents, maintenance and equipment repair. The calibration characteristic is considered stable if the measured concentration value of the calibration solution differs from the specified value by no more than 15%. If the calibration characteristic is unstable, it is necessary to find out and eliminate the reasons and repeat the stability control. If it is exceeded again, the chromatograph is re-calibrated.
5.8.7 Taking measurements
Sample analysis begins as quickly as possible. If it is impossible to carry out the analysis within 3 hours from the moment of sampling, the sample is placed in a refrigerator and stored for no more than 1 day at a temperature of (2-8) *C.
The chromatograph is brought into operating mode in accordance with the operating instructions.
Sample preparation: the analyzed sample of an aqueous solution of sodium hypochlorite is diluted with water for laboratory analysis at least 200 times (1 cm 3 of the original sample is diluted in a volumetric flask with a capacity of 200 cm 3). A diluted sample of sodium hypochlorite solution is filtered using a syringe and a filter attachment with a pore diameter of 0.45 μm. Helium is intensively bubbled through the collected filtrate using a capillary for 5-10 minutes. The prepared sample is poured into the liquid. cover with a protective lid. Further analysis is carried out in accordance with the chromatograph operating instructions. The result of the analysis is taken as the result of a single measurement.
If the concentration exceeds the upper limit of measurement according to the established calibration characteristic, the sample is diluted more times and the concentration is re-measured.
5.8.8 Processing results
5.8.8.1 Mass concentration of chlorite ions (CL2’) in the analyzed sample, g/dm3, is calculated using formulas (7) and (8)
TO,
’merning flasks
where C su is the mass concentration of chlorite ions, found using the chromic processing program
matographic data in a diluted sample, in accordance with the calibration characteristic. mg/dm 3:
K p - dilution factor of the original sample;
V M«PH flask - Volume of the volumetric flask, cm 3;
Ulrovy - sample volume of an aqueous solution of sodium hypochlorite.
5.8.8.2 Mass concentration of chlorate ion<СЮ 3 ~) в анализируемой пробе, г/дм 3 , вычисляют по формуле (9)
^syu, Kr 1000
where C ω - is the mass concentration of chlorate ions found using a program for processing chromatographic data in a diluted sample, in accordance with the calibration characteristic. mg/dm 3 ;
Kp is the dilution factor of the original sample according to formula (8).
5.8.8.3 Mass concentration of chlorate ion in the analyzed sample. % active chlorine, calculated using formula (10)
Heyu-/™ 1 10 °- (10 >
where Xiu is the mass concentration of chlorate ions, calculated according to formula (9). g/dm 3 ;
C actklor - mass concentration of active chlorine in the analyzed sample, found according to 5.5 of this standard.
GOST R 57568-2017
5.8.8 4 Mass concentration of bromate ions in the analyzed sample, mg/dm3. calculated using formula (11)
*vgO, ~ s vu, *#> (^)
where Cv - is the mass concentration of bromate ions found using a program for processing chromatographic data in a diluted sample, in accordance with the calibration characteristic. mg/dm 3 ;
Kp is the dilution factor of the original sample, formula (8).
The arithmetic mean of the results of two parallel determinations is taken as the result of the analysis. the absolute discrepancy between which does not exceed the repeatability limit in accordance with Table 7. with a confidence probability of P = 0.95.
Table 7 - Metrological characteristics for determining the content of chlorites, chlorates and bromochloride by ion chromatography
5.9 Determination of element content (Fe. As. Cd. Cr. Hg. Nl, Pb. Sb. Se) by inductively coupled plasma atomic emission spectrometry
5.9.1 Essence of the method
The method is based on measuring the atomic emission spectra of the determined elements excited in an inductively coupled plasma. The intensity of spectral pinions at wavelengths characteristic of each element is recorded by a photosensitive device, measured and processed by a computer system.
The difference in the intensity of the spectral line of the element and the background is taken as the analytical signal.
5.9.2 Equipment, reagents, solutions, glassware
Atomic emission spectrometer with inductively coupled plasma with characteristics: generator frequency 27.12 MHz. spectral range (180-770) nm. spectral resolution s 0.012 nm. axial and/or radial plasma observation. To analyze an aqueous solution of sodium hypochlorite, use a high-salt sample burner with an argon humidifier. Non-automatic scales in accordance with GOST R 53228 of at least class II accuracy with a division value of at least 0.001 g.
Volumetric flasks 2-20.50.100.250, 500.1000-2 according to GOST 1770.
Graduated pipettes 1-1-2-1, 2, 5.10. 20. 25 according to GOST 29227.
Measuring cylinders 1-100.1000-2 according to GOST 1770.
Laboratory dispensers, desktop (mounted on a vessel) or manual, single-channel with a fixed or variable volume (0.01-10) cm 3 of dosing according to GOST 28311.
Glasses V-1-50.100. 250 TCS made of borosilicate glass according to GOST 25336.
Standard samples of the composition of solutions of the elements being determined.
Multielement standard solution containing As. Be. Cd. Cr, Se. Hg. Ni. Pb, Tl, mg/dm 3, nominal concentration 100 mg/dm 3 and permissible error of the certified value ± 1 mg/dm 3.
Nitric acid, special purity grade. according to GOST 11125.
Hydrogen peroxide H 2 0 2 (29-32) % analytical grade. according to GOST 10929.
Argon gas of high purity according to GOST 10157.
GOST R 57568-2017
Helium is compressed with a mass fraction of the main substance of at least 99.5%.
Water for laboratory analysis, purity level 2 according to GOST R S2501.
Universal indicator paper.
5.9.3 Preparation for analysis
Preparing the device for operation and optimizing measurement conditions is carried out in accordance with the operating instructions for the device.
5.9.4 Preparation of calibration solutions
Series of multi-element calibration solutions can be prepared from single-component GSO, multi-component GSO and imported multi-element solutions.
5.9.4.1 Preparation of basic calibration solution No. 1
Basic multi-element solution No. 1 is prepared from the corresponding single-component or multi-component GSO composition of aqueous solutions of elements determined in sodium hypochlorite solutions as follows. so that the final nominal mass concentrations of element ions in solution are 50 mg/dm 3 .
Open an ampoule of a standard solution containing 1 mg/cm3 of the element. 2.5 cm 3 of the standard solution is transferred to a volumetric flask with a capacity of 50 cm 3. Fill to the mark with a 5% solution of nitric acid and mix. The shelf life of the solution is 3 months at a temperature of (2-8) *C.
5.9.4.2 Preparation of basic calibration solution No. 2
The main multi-element solution No. 2 is prepared from the corresponding single-component or multi-component GSO composition of aqueous solutions of elements determined in sodium hypochlorite solutions, so that the final nominal mass concentrations of element ions in the solution are 10 mg/dm 3.
Open an ampoule of a standard solution containing 1 mg/cm3 of the element. 1.0 cm 3 of the standard solution is transferred to a volumetric flask with a capacity of 100 cm 3. Fill to the mark with a 5% solution of nitric acid and mix. The shelf life of the solution is 2 months at a temperature of (2-8) *C.
5.9.4.3 Preparation of matrix calibration solutions with additions of elements 1: 0.5 and 0.1 mg/dm 3
A calibration scale for solutions is prepared on a real sample of an aqueous solution of sodium hypochlorite using the additive method.
Matrix calibration solutions are prepared by diluting in a volumetric flask in accordance with Table 8. Make up to the mark with a sodium hypochlorite matrix solution prepared according to 5.9.6.
Table 8 - Preparation of matrix calibration solutions using the additive method when analyzing an aqueous solution of sodium hypochlorite
It is allowed to prepare solutions other than those indicated in Table 8, including increasing the range of the calibration characteristic in accordance with the capabilities of the device.
5.9.5 Spectrometer calibration
Calibration solutions are sprayed into the burner flame and the emission intensity for each element is recorded at the required wavelength using the additive method.
GOST R 57568-2017
Calibration solutions of each element being determined must cover the entire working range of measuring its mass concentration in samples and are measured in order of increasing mass concentration of the element being determined.
The blank sample is an aqueous solution of sodium hypochlorite (see 5.9.6).
After constructing the calibration characteristics, a solution of 5% nitric acid is used to remove high concentrations of elements and eliminate the adsorption of metals, running it through the sample introduction and spraying system for at least 15 minutes. and then water for laboratory analysis for 5 minutes.
Monitoring the stability of the calibration characteristic
Every 30 samples, repeat the measurement for one of the calibration solutions. The calibration characteristic is considered stable if the following condition is met for each control sample:
where C„ is the measured value of the mass concentration of the element in the calibration solution, mg/dm 3 ;
C is the actual value of the mass concentration of the element in the calibration solution, mg/dm 3 ;
G - standard for monitoring the stability of the calibration characteristic. G =15%.
If the measured concentration for this solution differs from the true concentration by more than 15%. The calibration is repeated completely again.
5.9.6 Preparing samples of aqueous sodium hypochlorite solution and performing measurements
Preparation of aqueous sodium hypochlorite samples is carried out only in a fume hood!
A sample of an aqueous solution of sodium hypochlorite is thoroughly mixed and 20 cm 3 of solution is taken using a pipette. Transfer to a glass with a capacity of 100 cm3, carefully, drop by drop, add the volume of hydrogen peroxide calculated by formula (13)
y d %IOS1, 0chaOSg34"100
1000-70.9 W Hi0i pH)0 / *
where VMaOS is the volume of an aliquot of an aqueous solution of sodium hypochlorite taken for analysis, cm 3 ;
C Na0CI is the mass concentration of active chlorine in the analyzed aqueous solution of sodium hypochlorite, g/dm 3 ;
W Hz0j - mass fraction of hydrogen peroxide (according to the reagent passport), %;
p H2C>2 - density of the hydrogen peroxide solution, g/cm 3 .
After the violent reaction stops, 1-2 cm 3 of concentrated nitric acid is added to the solution. The mixture is stirred. Helium is bubbled through the resulting solution for 10 minutes. then leave it under the hood for about 15 minutes. After 15 minutes, the solution is quantitatively transferred into a 100 cm 3 volumetric flask, washing the glass repeatedly with water for laboratory analysis. Bring the prepared sample to the mark with water for laboratory analysis.
The sample prepared in an appropriate manner is sprayed into a burner flame. The emission of each element is recorded at a pre-selected optimal wavelength at least twice. the obtained values are averaged and the content of the element in the sample is calculated from the average value.
5.9.7 Processing results
Mass concentrations of the elements being determined per 1 dm 3 of an aqueous solution of sodium hypochlorite are calculated using formula (14)
H*U-K r. (14)
where X is the mass concentration of the element being determined in the sample, mg/dm 3 ;
The final result of the analysis is taken as the result of a single measurement of the concentration of the element being determined in the working sample (Table 9). If necessary, the analysis is carried out under repeatability conditions (two parallel determinations).
GOST R 57568-2017
Table 9 - Metrological characteristics of the method for determining the content of trace elements using inductively coupled plasma atomic emission spectrometry
|
Definable |
Measuring range (inclusive) |
Accuracy indicator (relative error limits at probability P > 0.96) 16. H |
Repeatability limit (for two results of parallel determinations) t.H |
Reproducibility limit (for two analysis results) A. Ch |
|
From 0.2 to 20 | ||||
|
From 0.15 to 5 | ||||
|
From 0.05 to 10 | ||||
|
From 0.08 to 10 | ||||
|
From 0.25 to 10 | ||||
|
From 0.1 to 10 | ||||
|
From 0.25 to 10 |
6 Transportation, storage
6.1 Delivery and transportation of the product
6.1.1 an aqueous solution of sodium hypochlorite is supplied by all modes of transport, mainly by rail, in accordance with the rules for the transportation of dangerous goods in force for this type of transport (1).
6.1.2 Sodium hypochlorite solution is transported in containers made of polyethylene (PE) or polyvinyl chloride (PVC) with external glass fiber reinforcement (GFK). Tanks with a steel tank lined with rubber or other suitable artificial material may be used.
6.1.3 Containers for storing sodium hypochlorite solution should be filled to no more than 90% of the volume)