Some standard content:
National Standard of the People's Republic of China
Photographic grade anhydrous sodium sulfite
Photographic grade sodium sulfite, anhydrous This standard is equivalent to the international standard 1SO418-1976 "Specifications for anhydrous sodium sulfite for photographic grade". This product is a white powdery crystal, soluble in water. Molecular formula: NaSos
Molecular weight: 126.04 (according to the international atomic weight in 1985) Content and scope of application
GB10550-89
This standard specifies the technical requirements, test methods, inspection rules, packaging, marking, transportation and storage of photographic grade anhydrous sodium sulfite. This standard applies to anhydrous sodium sulfite for processing exposed photosensitive materials. 2 Reference standards
GB 601
Chemical reagents
GB602 Chemical reagents
GB603 Chemical reagents
Chemical tests
Preparation of standard solutions for titration analysis (volume analysis) Preparation of standard solutions for impurity determination
Preparation of preparations and products used in test methods Sampling and acceptance rules
GB6682 Laboratory water specifications
3 Technical requirements
The content of anhydrous sodium sulfite (Na2SO) is not less than 97.0%. 3.2 Maximum impurity content (indicators are expressed in percentage): %
Appearance of water fern
Calcium, magnesium and other ammonia insolubles
Thiosulfate (in terms of N2S20a)
Alkalinity (in terms of Nazcoai)
Heavy metal (in terms of Pbh Calculation)
Iron (Fe)
Silver nitrate ammonia carboxylation reaction
Test method
Determination of sodium sulfite (Na:SO:) content
Weigh 0.258 of the sample, weigh to 0,000"g, place in a 500mL membrane volumetric flask containing 50.00mL of iodine standard solution Lc (1/2I) = 0.1mol/L), add 10mL of hydrochloric acid solution (1+1), and titrate with sodium thiosulfate standard solution [e(NaS?0) = 0.1mol/L). Approved by the Ministry of Chemical Industry of the People's Republic of China on February 25, 19896
Implemented on December 1, 1989
GB 10550--89
When it is close to the end point, add 5mL of starch indicator solution (5g/L) and continue titrating until the blue color disappears. The content of anhydrous sodium sulfite is calculated according to formula (1): (50r1 * V: t2) × 0. 063 02Wu Zhong: —
-the percentage content of anhydrous sodium sulfite, %; c1—the concentration of iodine standard solution, mol/L,
:--…the concentration of sodium thiosulfate standard solution, mul/L, V—the amount of sodium thiosulfate standard solution, mL;-·-the mass of the sample + 8
0.06302——the equivalent number of grams per millimole of sodium sulfite (1/2Na, SO:). 4.2 Determination of impurity content
4.2.1 Appearance of aqueous solution
Weigh 20 g of the sample, weigh to the nearest 0.1; dissolve in water, dilute to 100 mL, and stir. The test solution shall not show obvious turbidity or sediment, but a small amount of flocculent matter is allowed.
4.2.2 Calcium, magnesium and other ammonia insolubles
Weigh 10 g of the sample, accurate to 0.1, dissolve in 75 mL of water, add 5 mL of ammonium oxalate solution (40 g/L), 2 mL of ammonium hydrogen phosphate solution (100 g/L), and 10 mL of ammonia water (1+9), and 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 at 600±50 ℃ for 4 h. After cooling to room temperature in a desiccator, weigh it, accurate to 1 mg. The weight of the residue shall not exceed 0.05 g. 4.2.3 Thiosulfate (Na25203)
4.2.3.1 Solution preparation
Sodium thiosulfate standard solution: dilute 5.00 mE sodium thiosulfate standard solution Ce(NagS:0s) =0.100 0 mol/L) to 1 mL.
Potassium bromide-mercuric chloride solution: dissolve 25g potassium bromide and 25g mercuric chloride in 900mL 50°C water, cool to room temperature, dilute to 1000mL, and let stand overnight. Filter if turbid. 4.2.3.2 Analysis steps
Weigh 26 g of the sample, weigh to 0.1 g, dissolve in water, and dilute to 100 mL. Pipette 0.5 μL and slowly add it to a 50 mL Nessler colorimetric tube containing 1 mL of potassium bromide-mercuric chloride solution. Let stand at room temperature for 10 min (do not stir). Then stir carefully to make the milky color evenly distributed. Immediately compare with the standard push solution. The milky color should not be greater than the standard. The standard is to take 0.25mL of sodium thiosulfate standard solution, and follow the analytical steps described above, starting from "slowly adding to a 50mL Nessler colorimetric tube containing 10mL of potassium iodide-chloride solution", and treat it in the same way as the sample solution. 4.2.4 Alkalinity (in terms of NacOs)
Weigh 5g of the sample, accurate to 0.01g, and dissolve in 50mL of water without carbon dioxide. Add 100mL of hydrogen peroxide neutral solution and cool to room temperature. Then add 2 drops of methyl red indicator solution (1/L) and titrate with hydrochloric acid standard solution [c(HCI)=0.1mol)/L. Until the solution changes from light yellow to red.
Note: Dilute hydrogen peroxide according to (1+9), indicate with methyl red indicator (1g/L), and neutralize with sodium hydroxide solution C(NaOH)-0.1mol/L2. The content of sodium carbonate is calculated according to formula (2):
· c X 0. 053
Percentage of sodium carbonate, %
V—-Hydrochloric acid standard solution, mL;
GB 10550—89
eConcentration of hydrochloric acid standard solution, mol/L;
m——Sample mass.g;
0.053.Number of grams equivalent to each millimole of sodium carbonate (1/2Na.CO3). 4.2.5 Heavy metals (in terms of Pb Calculation)
Weigh 2g of the sample, accurate to 0.1g, dissolve in 25mL of water, add 15mL of hydrochloric acid, place on a water bath and evaporate to dryness, and dissolve the residue with 25mL of water. Add 2 drops of p-nitrophenol indicator solution (2.5g/L), add ammonia water (1+9) until the solution turns yellow, then add hydrochloric acid solution (1+99) until the solution becomes colorless, and add 2.5mL in excess. Transfer to a 50mL volumetric flask, dilute to the scale with water, and mix. Transfer 20mL of the above test solution (the remaining test solution is used to measure iron), place it in a 50mL naphthalene colorimetric tube, add 5mL of saturated hydrogen sulfide solution, dilute to the scale, and mix. The color of the test solution shall not be darker than the standard.
The standard is to take 0.04 4.2.6 Iron (Fe) Www.bzxZ.net
Pipette 20mL of the test solution (the remaining test solution in 4.2.5) into a 50mL Nessler colorimetric tube, add 2mL of hydroxylammonium fluoride solution (100g/L), mix well, and stand for 10 min. Add 2mL of acetic acid·sodium acetate buffer solution (pH=5.0), add 2mL of o-phenanthroline solution (1 g/L), dilute to 50mL with water, and mix. The color of the test solution shall not be darker than that of the standard. The standard is 0.06 mB Iron (Fe) impurity standard solution, treat it in the same way as the sample. 4.2.7 Reaction of silver nitrate ammonia solution
Weigh 2 samples, weigh to 0.01, place in a 50mL volumetric flask, add water to dissolve and dilute to the scale, mix well. Pipette 20mL of the above test solution into a 50mL colorimetric tube, and add 10mL of newly prepared silver nitrate ammonia solution [equal volumes of ammonia water and silver nitrate solution (1008/L) mixed], the color or precipitation of the mixed test solution should not exceed the blank. The blank is to transfer 20mL of the remaining test solution into a 50mL colorimetric tube, add 5ml of ammonia water and 5mL of water, and shake well. Note that after this test, all test solutions should be disposed of immediately and the container should be cleaned to prevent the formation of explosive compounds after standing. 5 Inspection rules
5.1 This product should be inspected by the quality inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that all products shipped meet the requirements of this standard.
5. 2 The user 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 any one of the inspection results does not meet the requirements of this standard, re-sampling shall be carried out from twice the packaging bags. If even one of the re-inspection results does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5.5 When the supplier and the buyer have any objection to the product quality, the two parties can negotiate to resolve it. If arbitration is required, it shall be handled in accordance with the provisions of the "Interim Measures for National Product Quality Arbitration Inspection".
6 Packaging, marking, transportation and storage
6.1 Packaging
The packaging unit is 50kg. The first layer of the inner packaging is a polyethylene bag sealed. The second layer is a kraft paper bag with a seam. The outer packaging is a woven bag with a seam. If special packaging is required, it shall be agreed upon by the supplier and the buyer. 6.2 Marking
The packaging container shall be accompanied by a product certificate. The outer packaging bag 1 shall have the product name, standard number, registered trademark, net weight, gross weight, and production batch description:
1 Compared with IS0,419-1976, inspection rules have been added 2 Compared with ISO419-1976, marking, packaging, transportation and storage have been added. 8
GE70550—89
No., period, manufacturer name and address, and printed with "moisture-proof\". 6:3 Transportation
During transportation, the product should be loaded and unloaded gently, and should be protected from heat, moisture, impact, and hooks. 6.4 Storage
The product should be stored in a 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. The main drafters of this standard are Huang Weiqi, Lu Bende, Chen Shaozeng, and Zhong Zijing. From the date of implementation of this standard, the original Ministry of Chemical Industry standard HG7—1355-80 "Photographic Grade Sodium Sulfite" will be invalid.
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