Some standard content:
1 Scope
HG/T2777-1996 Stable chlorine dioxide solution This standard specifies the requirements for stable chlorine dioxide solution, sampling test methods, and marking packaging, transportation and storage. This product is mainly used for drinking water, industrial water treatment, and sterilization and algae disinfection of equipment and blood in the food industry and medical industry.
Molecular formula: CIO2
Relative molecular mass: 67.452 (according to the 1993 international relative atomic mass) 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards.
GB191-90 Pictorial marking for packaging, storage and transportation (neqISO780:1985)GB/T601-88 Preparation of standard solution for titration analysis (volume analysis) of chemical reagentsGB/T602-88 Preparation of standard solution for determination of impurities of chemical reagents (neqISO6353/1:1982)GB/T603-88 Preparation of preparations and products used in test methods of chemical reagents (neqISO6353/1:1982)GB/T610.1-88 General method for determination of arsenic by chemical reagents (monumental method)GB/T1250-89 Method for expressing and determining limit valuesGB/T6678 -86 General rules for sampling of chemical products
GB/T6682-92 Specifications and test methods for water used in analytical laboratories (eqvISO3696:1987) 3. Requirements
3.1 Appearance: colorless or slightly yellow transparent liquid, no suspended matter Stability Chlorine dioxide solution should meet the requirements of Table 1: Table 1
Chlorine dioxide (CIO2) content
Density (25c) g/cm3
Arsenic (As) content
Heavy metal (in terms of pb) content
1.020-1.060
4.1 Determine the number of sampling units according to the provisions of GB/T66786.6. 4.2 Use a sampling glass tube to slowly insert the container at 2/3 of the depth for sampling. Mix the sampled products, and the total amount of not less than 500ml is respectively put into two clean and dry brown bottles and sealed. Put a label on the bottle, indicating the manufacturer's name, product name, product batch number and sampling date. One bottle is for inspection and the other is kept for reference. 4.3 If one of the indicators in the test results does not meet the requirements of this indicator, it should be re-sampled from twice the packaging unit for verification. If one of the verification results does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5 Test method
The reagents and water used in this method are analytical pure reagents and grade 3 water specified in GB/T6682 unless otherwise specified.
The standard solution impurities, standard solution preparations and products required in the test are prepared in accordance with the provisions of GB/T601'GB/602°G/603 unless otherwise specified. The rounded value comparison method specified in GB/T1250 is used to determine whether the test results meet the standards. 5.1 Determination of chlorine dioxide content
5.1.1 Summary of the method
Stability Chlorine dioxide solution releases oxidizing chlorine dioxide under acidic conditions. Chlorine dioxide oxidizes potassium iodide to release iodine, and then the iodine precipitated by the reaction is titrated with sodium thiosulfate standard titration solution. 5.1.2 Reagents and materials
5.1.2.1 Sulfuric acid solution: 1+1
5.1.2.2 Potassium iodide.
5.1.2.3 Sodium thiosulfate standard titration solution: c (Na2S203) about 0.1 mol/L. 5.1.2.4 Soluble starch solution: 5g/L, the shelf life is two weeks. 5.1.3 Analysis steps
Weigh about 2g of sample (accurate to 0.0002g), place in a 250mL iodine volumetric flask pre-added with 50mL water and 2g potassium iodide, add 3mL sulfuric acid solution, mix well. Place in a dark place for 10min, titrate with sodium thiosulfate standard titration solution, add 1~2mL starch indicator solution when approaching the end point, continue titrating until the blue disappears, and perform a blank experiment at the same time
5.1.4 Expression of analysis results
Calculate the chlorine dioxide (CIO2) content (x) expressed as mass percentage: (V-V0)XcX0.01349|| tt||Where: V-..
--the volume of sodium thiosulfate standard titration solution consumed during titration, mlVO--------the volume of sodium thiosulfate standard titration solution consumed during blank test, mlc--....-the actual concentration of sodium thiosulfate standard titration solution, mol/Lm------the mass of the sample, g
0.01349--------the mass of chlorine dioxide (C1O2) expressed in grams equivalent to 1.00mL sodium thiosulfate standard titration solution [c(Na2S203)-1.000mol/L]. 5.1.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.01%. 5.2 Determination of density
5.2.1 Instruments and equipment
5.2.1.1 Densitometer: graduation value is 0.001g/cm35.2.1.2 Constant temperature water bath: can control the temperature of 20+-1C5.2.1.3 Thermometer: graduation value is 1C.
5.2.1.4 Measuring cylinder: 500mL.
5.2.2 Determination steps
Pour the stable chlorine dioxide solution sample into a clean and dry measuring cylinder without bubbles. Place the measuring cylinder in a constant temperature water bath of 20+1C. After the temperature is constant, slowly put the densitometer into the sample. After the densitometer is stable in the sample, read the scale of the lower edge of the meniscus of the densitometer (except for the densitometer marked with the scale of reading the upper edge of the meniscus), which is the density of the sample at 20C. 5.2.3 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.003g/cm2
PH value determination
5.3.1 Reagents and materials
5.3.1.1 Potassium dihydrogen phosphate-sodium dihydrogen phosphate buffer solution5.3.1.2 Borax buffer solution: pH-9.185.3.2 Instruments and equipment
General laboratory instruments and acidity meters: accuracy 0.01pH unit, equipped with glass measuring electrodes and saturated calomel reference electrodes or composite electrodes.
5.3.3 Determination steps
After positioning with two buffer solutions, pour the sample solution into the beaker, immerse the electrode in the solution to be tested, and read the pH value when it is stable (the change in pH within 1 minute is not greater than 0.1).
5.3.4 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute value of the two parallel determination results shall not exceed 0.1 pH unit. 5.4 Determination of arsenic content (arsenic spot method)
5.4.1 Principle
In an acidic solution, potassium iodide and stannous chloride are used to reduce As(V) to As(II). Zinc particles are added to react with the acid to produce new ecological hydrogen, which further reduces As(III) to arsine. When arsine gas reacts with mercuric bromide test paper, brown-yellow mercury-arsenic compounds are produced, which can be used for visual colorimetric determination of arsenic. 5.4.2 Reagents and materials
5.4.2.1 Hydrochloric acid
5. 4.2.2 Potassium iodide
5.4.2.3 Stannous chloride solution: 400g/L
5.4.2.4 Sodium hydroxide solution: 100g/L
5.4.2.5 Arsenic-free zinc particles
5.4.2.6 Lead acetate cotton
5.4.2.7 Mercuric bromide test paper
5.4.2.8 Arsenic standard stock solution: 1mL contains 0.1mgAs5.4.2.9 Arsenic standard solution: 1mL contains 0.001mgAs. Pipette 10.00mL of arsenic standard stock solution into a 100mL volumetric flask, add 1mL of hydrochloric acid solution, dilute to the mark with water, and mix. When using, pipette 10.00mL of this solution into a 100mL volumetric flask, dilute to the mark with water, and mix.
5.4.3 Instruments and equipment
General laboratory instruments and arsenic analyzers: Same as 5.2 of GB/T610.1 5.4.4 Analysis steps
Weigh 1.00+0.01g of sample and place it in the wide-mouth bottle of the arsenic analyzer. In the wide-mouth bottle of another arsenic analyzer, accurately add 3.00mL of arsenic standard solution, add 6mL of hydrochloric acid, add water to about 70mL, add 1g of potassium iodide and 0.2mL of stannous chloride solution, shake well, let it stand for 10 minutes, add 2.5g of arsenic-free zinc to each, and immediately assemble the device according to the diagram in GB/T610.1, and place it in a dark place at 25-30g for 1-1.5h. Compare the color of the mercuric bromide test paper to determine whether the arsenic content meets the standard. 5.5 Determination of heavy metal content (in terms of Pb) 5.5.1 Principle
Lead ions and sulfide ions generate colored lead sulfide precipitation in acetic acid medium. When the lead content is low, a stable dark suspension is formed, which can be used for visual colorimetric determination.
5.5.2 Reagents and materials
5.5.2.1 Hydrochloric acid
5.5.2.2 Acetic acid solution: 1+2
5.5.2.3 Saturated hydrogen sulfide water
5.5.2.4 Lead standard stock solution: 1mL contains 0.1mgPb 5.5.2.5 Lead standard solution: 1mL contains 0.002mgPb. Take 10.00mL of lead standard stock solution, place it in a 500mL volumetric flask, dilute to the mark with water, and shake well. This solution is prepared before use. 5.5.3 Analysis steps
Weigh 1.00+0.01g sample and add 2mL hydrochloric acid. Boil on an electric stove until almost dry, remove and cool to room temperature, and transfer to a 25mL colorimetric tube. Transfer 10.00mL of lead standard solution to another colorimetric tube, add 0.2mL of acetic acid solution, dilute with water to about 25mL, add 10mL of freshly prepared saturated hydrogen sulfide water, shake well, let stand for 10min, and compare the dark color to determine whether the lead content meets the standard.
6 Marking, packaging, transportation, storage
6.1 Stability The packaging container of chlorine dioxide solution should be painted with firm markings, including: manufacturer name, product name, trademark, production date or batch number, net weight, factory address, and the "upward" and "heat-afraid" marks specified in GB191. 6.2 Each batch of stable chlorine dioxide solution shipped out of the factory should be accompanied by a quality certificate, including: product name, manufacturer name, brand, net weight, batch number, production date, proof that the product quality complies with this standard, and this standard number. 6.3 Stable chlorine dioxide solution is packaged in light-proof polyethylene or polypropylene plastic barrels, and the packaging specifications are determined according to user needs. Www.bzxZ.net
6.4 Stable chlorine dioxide solution cannot be stored or transported together with acid. 6.5 The storage period of stable chlorine dioxide solution is one year.
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