This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of chemical reagent ascorbic acid. This standard applies to the inspection of chemical reagent ascorbic acid. GB/T 15347-1994 Chemical reagent ascorbic acid GB/T15347-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical reagent
L-Ascorbic acid
GB/T 15347--94
-Part 3: Specifications-Batch 2"
This standard is equivalent to the international standard ISO6353--3:1987 "Chemical analysis reagents-R70\ascorbic acid".
This reagent is a white crystal or crystalline powder, easily soluble in water, insoluble in benzene and ether, and has an acidic reaction in aqueous solution. It is a strong reducing agent. Molecular formula: CH.O.
Structural formula:
Relative molecular mass: 176.13 (according to the 1991 international relative atomic mass) 1 Subject content and scope of application
This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of chemical reagent ascorbic acid. This standard applies to the inspection of chemical reagent ascorbic acid. 2 Reference standards
GB/T 601
GB/T602
GB/T 603
GB/T 613
GB/T 619
GB/T6682
GB/T 9728
GB/T9729
GB/T 9735
GB/T 9739
GB/T 9741
HG 3—119
Chemical reagents
Preparation of standard solutions for titration analysis (volumetric analysis)Chemical reagents
Chemical reagents
Chemical reagents
Chemical reagents
Preparation of standard solutions for determination of impurities
Preparation of preparations and products used in test methodsGeneral method for determination of specific rotation
Sampling and acceptance rules
Specifications and test methods for water used in analytical laboratoriesChemical reagents
Chemical reagents
Chemical reagents
Chemical reagents
Chemical reagents
Chemical reagents
General method for determination of sulfate
General method for determination of chloride
General method for determination of heavy metals
General method for determination of iron
General method for determination of residue on ignition
Packaging and marking
HG/T 3-1168
Preparation and determination of chemical reagent clarity standards (glass emulsion method) Approved by the State Administration of Technical Supervision on December 22, 1994 1130
Implementation on October 1, 1995
3 Technical requirements
GB/T15347—94
3. 1Ascorbic acid (CHO) content: not less than 99.7%. 3.2Specific optical rotation [a]: +20.5°～+21.5°. 3.3Maximum impurity content:
Clarity test
Ignition residue (calculated as sulfate)
Loss on drying
Chloride (CI)
Sulfate (SO))
Iron (Fe)
Heavy metal (calculated as Pb)
4Test method
Analytically pure
The standard titration solution, impurity standard solution, preparation and product in this test method shall be prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603 unless otherwise specified. The experimental water shall meet the third-grade water specifications in GB/T6682. 4.1 Determination of ascorbic acid (CH:O.) contentWww.bzxZ.net
Weigh 0.3 g sample, accurate to 0.0001 g, dissolve in 80 mL water, add 2 mL sulfuric acid solution (20%), shake well, and immediately titrate with iodine standard titration solution [c(1/212)=0.1 mol/L). When it is close to the end point, add 3 mL starch indicator solution (10 g/L) and continue titrating until the solution turns blue, and keep it for 30 seconds.
The content is calculated according to formula (1):
X, = V·c×0 08.06 × 100
Wherein: X, — mass percentage of ascorbic acid, %; volume of iodine standard titration solution consumed by the sample, mL; — actual concentration of iodine standard titration solution, mol/L, 0. 088 06-
（1）
The mass of ascorbic acid in grams equivalent to 1.00mL iodine standard titration solution (c(1/212)=1.000mol/L),
The mass of the sample,.
4.2 Specific rotation
Weigh 5g of sample to an accuracy of 0.0001g, dissolve in water, transfer to a volumetric flask, dilute to 50mL, and measure according to the provisions of GB/T 613. The result is calculated according to formula (2) in GB/T 613.
4.3 Determination of impurities
The sample must be weighed accurately to 0.01g.
4.3.1 Clarity test
Weigh 10g of sample and dissolve it in 100mL of water. Its turbidity shall not be greater than the No. 3 clarity standard specified in HG/T3-1168. 4.3.2 Residue on ignition
GB/T 15347-94
Weigh 2g of sample and place it in a crucible that has been kept constant at 650±50℃. Determine it according to the provisions of Article 4.1 of GB/T9741. The results are calculated according to the provisions of Chapter 5 of GB/T 9741. 4.3.3 Loss on drying
Weigh 2g of sample accurately to 0.0001g and place it in a weighing bottle that has been dried to constant weight at 105±2℃. Dry it in an electric oven at 105±2℃ to constant weight.
The loss on drying is calculated according to formula (2):
X2 = ml2m2 × 100
Where: X, — loss on drying, %;
ml — — mass of the sample before constant weight, g,
m — mass of the sample after constant weight, g.
4.3.4 Chloride
Weigh 1g of sample, dissolve in water, and dilute to 10mL. Take 2mL, add 1mL nitric acid, shake thoroughly, and dilute to 10ml. Heat in warm water for 1min, cool, dilute to 20mL, and measure according to the provisions of GB/T9729. The turbidity of the solution shall not be greater than the standard. The standard is to take an impurity standard solution containing 0.01mg chloride, dilute to 20mL, and treat it in the same way as the sample solution of the same volume. 4.3.5 Sulfate
Weigh 1g sample, dissolve in 10mL water, add 0.5mL hydrochloric acid solution (20%), and measure according to the provisions of GB/T9728. The turbidity of the solution shall not be greater than the standard.
The standard is to take an impurity standard solution containing 0.02mg sulfate, dilute it to 10mL, and treat it in the same way as the sample solution of the same volume. 4.3.6 Iron
Weigh 1g sample, dissolve in 15mL water, adjust the pH value of the solution to 2 with hydrochloric acid solution (15%), and measure it according to the provisions of GB/T9739. The red color of the solution shall not be darker than the standard. The standard is to take an impurity standard solution containing 0.002mg iron, dilute it to 15mL, and treat it in the same way as the sample solution of the same volume. 4.3.7 Heavy metals
Weigh 1g of sample, dissolve in 10mL of water, add 1g of anhydrous sodium acetate, shake, add 0.2mL of acetic acid solution (30%), dilute to 25mL, and measure according to the provisions of GB/T9735. The dark color of the solution shall not be darker than the standard. The standard is to take an impurity standard solution containing 0.01mg of lead, add 1g of anhydrous sodium acetate, add 15mL of water to dissolve, adjust the pH value of the solution to 4~~5 with acetic acid solution (30%), dilute to 25mL, and treat it in the same way as the sample solution of the same volume. 5 Inspection rules
Sampling and acceptance shall be carried out according to the provisions of GB/T619. 6 Packaging and marking
According to the provisions of HG3-119, among which:
Inner packaging form: Gz-2
Outer packaging form: W-5
Packing unit: Class 2.
Additional Notes:
GB/T15347—94
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Beijing Chemical Reagent Factory. This standard was drafted by Nanjing Chemical Reagent Factory. The main drafter of this standard is Shi Jianxiang.
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