L-Cystine check

Acidity take this product 1.0g, add water 100ml, fully shaking determination (Appendix Ⅵ H) according to the law, pH value should be 5.0 to 6.5. Transmittance solution to take the product 1.0g, plus 1mol / L hydrochloric acid solution 20ml dissolved, according to spectrophotometry (Appendix Ⅳ A), measured at a wavelength of 430nm light transmittance of not less than 98.0%. Chloride take the goods 0.50g, after adding dilute nitric acid to dissolve 10ml, add water to make into a 50ml, dispensing 25ml, check (Appendix Ⅷ A) according to the law, compared with standard control solution made ​​of sodium chloride solution 5.0ml, not thicker (0.02%). Sulfate take the goods 0.70g, add dilute hydrochloric acid and shake to dissolve 5ml, add water to make into a 40ml, according to inspection (Appendix Ⅷ B), 5ml compared with standard potassium sulfate solution 1.4ml dilute hydrochloric acid control solution made not more concentration (0.02%). Other amino acids take the goods, plus 1mol L hydrochloric acid solution / solution made ​​from 10mg per 1ml, thin layer chromatography (Appendix Ⅴ B) test, learn the solution 2μl, points on silica gel G plate to positive butanol – water – acetic acid (5:2:1) as the agent, after the commencement of dried, sprayed with acetone solution (1 → 50) ninhydrin, dried at 80 ℃ 10 minutes and immediately view, in addition to the main spots, shall not significant other spots. Drying of the product, dried at 105 ℃ 3 hours, less weight loss should not exceed 0.2% (Appendix Ⅷ L). Residue on ignition to take this product 1.0g, according to inspection (Appendix Ⅷ N), no residue left over 0.1%. Iron salt residue on ignition key under the residue left over, add 1ml of nitric acid, evaporated on a water bath, add dilute hydrochloric acid 4ml, after tepid dissolved, moved to 50ml of Nessler tube, according to inspection (Appendix Ⅷ G), compare and contrast 1.0ml solution made with standard iron solution, not deeper (0.001%). Heavy metals in the product 1.0g, according to inspection (Appendix Ⅷ H Third Law), containing heavy metals should not exceed ten parts per million. Arsenic take this product 2.0g, dissolved in 23ml water, add 5ml of hydrochloric acid, check (Appendix Ⅷ J First Act) law, shall comply with the provisions of (0.0001%).