Some standard content:
National Standard of the People's Republic of China
Photographic grade sodium thlosulfate
Photographie grade sodium thlosulfate, crystillineGB 10551- 89
Special: H
This standard is equivalent to the international standard ISO119-1976 "Specifications for photographic grade sodium thiosulfate". This product is colorless crystals, soluble in water, insoluble in butyl alcohol, molecular formula: Na2S05H0
Molecular weight: 248.2 (according to the International Atomic Energy Agency in 1985) Subject content and scope of application
3023-118
This standard specifies the technical requirements, test methods, inspection rules, packaging, marking, transportation and storage of photographic grade sodium thiosulfate. This standard applies to sodium thiosulfate used in the processing of exposed photosensitive materials. 2 Reference standards
GB 602
GB 603
Chemical reagents - Preparation of standard solutions for titration analysis (volume analysis) Chemical reagents
Preparation of standard solutions for impurity determination
Preparation of preparations and products used in test methods Chemical reagents
GB610 Sampling and acceptance rules for chemical reagents
GD6682
3 Technical requirements
Laboratory water specifications
3.1 Sodium thiosulfate (Na2S20x6H20) content: 99.0%~101.0%. 3.2 pH value: 6.5~-9.5.
Maximum impurity content (in percentage): 3.3
Appearance of aqueous solution
Sulfide (in S)
Calcium, iodine and other impurities
Heavy metals (in S)
Iron (Fe)
Test method
Determination of sodium thiosulfate (NaS,O5H,O) content 14.1
Instructions:
According to ISO1191972, the sample should be directly extracted with standard solution after being dissolved in water. This method uses aldehyde to extract Na2S2Os and adds buffer solution to ensure titration in slightly acidic environment.
Approved by the Ministry of Chemical Industry of the People's Republic of China on February 25, 1989, and implemented on December 1, 1989
GB10551—89
Weigh 10 g of sample to 0.001°, dissolve it in water without carbon dioxide, transfer it to a 500 mL volumetric flask after it is completely dissolved, dilute to the mark, and add the hook. Transfer 25mL of the above test solution to a 500mL iodine volumetric flask, add 0.10mL of neutral formaldehyde solution (take formaldehyde solution (37+63), add 2 drops of phenolic acid indicator solution (10g/), add sodium hydroxide solution c(Na0H) = 0.1mol/L) until light red appears), let stand for 5min, add 10mL of acetic acid-sodium acetate buffer solution (pH5), add 3mL of starch indicator solution (5g/L), and titrate with iodine standard solution (cL) until the test solution overflows and does not disappear within 1min as the end point. The acidification and titration time shall not exceed 5min. The content of sodium thiosulfate (NaS,0·5H,0) is calculated as follows: #-+*×0.248 2 × 100
Wherein: r——the white content of sodium thiosulfate, %; c——the concentration of iodine standard solution, mL; 8
——the concentration of iodine standard solution, mg/L; the mass of the sample is the number of grams equivalent to each milliliter of sodium thiosulfate (NazS20·5H20). 0. 248 2-
4.2pHll value determination
I2)- 0. 1 mol/
Weigh 20 samples, weigh to 0.1g, dissolve in about 80mL of freshly boiled and cooled water, dilute to 100mL. Determine with a pH meter at 20℃.
4.3 Impurity content is measured
4. 3.1 Appearance of aqueous solution
Weigh 40g of sample, accurate to 0.1, dissolve in water, dilute to 100mL, mix and test. The test solution shall not show obvious turbidity or sediment, but a small amount of flocculent is allowed.
4.3.2 Sulfide
Weigh 2g of sample, accurate to 0.1g, dissolve in 10mL of water, add 0.5mL of lead acetate solution (add enough sodium oxynitride solution (100g/L) to dissolve the formed precipitate and slightly in excess. Dilute to 50mL in a Nessler colorimetric tube and mix well. The dark color of the test solution shall not be darker than the standard.
The standard is to take 0.02mg of sulfide (S) impurity standard bath solution, put it in a 50mL Nessler colorimetric tube, and treat it in the same way as the sample. 4.3.3 Calcium, magnesium and other ammonia insolubles
Weigh 10g of sample, accurate to 0.1g, dissolve in 75mL of water, add 5ml of oxalic acid solution (40g/L), 2mL of phosphorus 10mL of diammonium hydrogen chloride solution (1008/L) and 10mL of ammonia water (1+9), let stand overnight. If a precipitate is formed, filter it with ash-free filter paper, wash it with ammonia water (1+39), and burn it in a high-temperature furnace at 600:50C for 4h. After cooling to room temperature in a T desiccator, weigh it to 1mg. The residual weight shall not be less than 0.02g.
4.3.4 Heavy metals (in terms of Pb)
Weigh 5g of the sample, weigh it to 0.1g, dissolve it in 20mL of water, add 5mL of nitrogen water (1+2), and slowly add 40ml of hydrogen peroxide solution (150g/L) in batches, let stand for 10min. Evaporate it to dryness on a water bath. Add 5mL of hydrochloric acid solution (1+1) and 5mL of water, and heat it to a boil. Dilute it with water to 10hml., transfer Take 20mL in a 50mL Nessler colorimetric tube (keep the remaining test solution for iron testing), add 2 drops of p-nitrophenol indicator solution (2.5g/1.). Add ammonia water (1+2) until the test solution turns yellow. Then add hydrochloric acid solution (1+99) until the test solution becomes colorless and add 2.5mL of 5mE saturated hydrogen sulfide solution in excess, dilute to 50mL. Mix well, the color of the test solution shall not be darker than the standard. The standard is to take 0.05mg of lead (Ph) impurity standard solution and treat it in the same way as the sample. 4.3-5 Iron
Pipette 5mL of the remaining test solution reserved in 4.3.4 into a 50mL Nessler colorimetric tube, add 15mL of thiocyanate alcohol solution (10g potassium thiocyanate dissolved in 10ml water, add 90mL of n-butanol, stir vigorously), and stir well. n. The red color of the test solution shall not be deeper than the standard. The standard is to take 0.15 mg of iron (Fe) impurity standard solution and treat it with the test sample. S Inspection Rules-1
GB10551
5.1 This product shall be inspected by the quality inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all products shipped meet the requirements of this standard:
5.2 The user unit has the right to inspect the received products in accordance with the provisions of this standard. 5.3 Sampling shall be carried out in accordance with the provisions of GB619.
5.4 If one of the test results does not meet the requirements of this standard, re-sampling shall be carried out in twice the amount of packaging bags. If only one indicator of the re-test result does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5.5 When the supply and demand parties have objections to the quality of the product, they can be resolved through negotiation between the two departments. When arbitration is required, it shall be handled in accordance with the provisions of the "National Product Quality Punching Inspection Interim Measures"
6 Packaging, Marking, Transportation and Storage"
6.1 Packaging
The packaging unit is 50g. The first layer of the inner packaging is a sealed polyethylene bag, the second layer is a kraft paper bag with a seam, and the outer packaging is a woven bag with a seam. If special packaging is required, it shall be agreed upon by the supply and demand parties. 6.2 Marking
The packaging container shall be accompanied by a product certificate. The outer packaging bag shall have the product name, standard number, registered trademark, net weight, gross weight, production batch, date, manufacturer's name and factory address, and be printed with the words "moisture-proof". 6.3 Transportation www.bzxz.net
The product should be loaded and unloaded gently during transportation to prevent moisture. Heat, rain, moisture, impact and loading and unloading are not allowed. 6.4 Storage
The product should be stored in a dry and cool place.
Additional instructions:
This standard was proposed by the National Photographic Material Standardization Technical Committee and is under the jurisdiction of the Photographic Material Technology Development Center of the Ministry of Chemical Industry. This standard was drafted by Guangzhou Photographic Chemical Materials and Shanghai Fluorescent Materials Factory participated in the drafting. The main drafters of this standard are Huang Weiqi, Lu Ben, Chen Shaozeng and Zhong Zijing. From the implementation of this standard, the original Ministry of Chemical Industry standard HG7:1354-80 "Photographic Grade Sodium Thiosulfate" will be invalid. Adoption instructions:
1] Compared with ISO419-1972, inspection rules have been added. 2] Compared with ISO41.9-1972, packaging, marking, transportation and purchase and storage have been added. 12
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