D-Cysteine Hydrochloride Monohydrate CAS 32443-99-5 (H-D-Cys-OH·HCl·H2O) Assay 98.5~101.0%

D-Cysteine Hydrochloride Monohydrate (H-D-Cys-OH·HCl·H2O) (CAS: 32443-99-5) AJI 97 Test Method
D-Cysteine Hydrochloride Monohydrate, when dried, containes not less than 98.5 percent and not more than 101.0 percent of D-Cysteine Hydrochloride (C3H7NO2S·HCl).
Solubility (H2O, g/100g): about 67 (25℃)
Identification: (1) To 5ml of a solution of D-Cysteine Hydrochloride Monohydrate (1→1000) add 0.5ml of pyridine and 1ml of 1% ninhydrin solution and heat for 3 minutes; a purple or purplish brown color is produced.
(2) To 5ml of a solution of D-Cysteine Hydrochloride Monohydrate (1→1000) and 2ml of 10% sodium hydroxide solution and two drops of 5% sodium nitroferricyanide solution; a red-purple color is produced.
(3) Take the small amounts of the test sample on the copper wire. Burn in the gas flame, then a green color is produced (Beilstein reaction).
Specific Rotation [α]20/D: Dried sample, C=8, 1mol/L HCl
State of Solution (Transmittance): 1.0g in 10ml of H2O, spectrophotometer, 430nm, 10mm cell thickness.
Chloride (Cl): 350mg, B-2
Ammonium (NH4): A-1
Sulfate (SO4): 1.2g, (1), ref: 0.50ml of 0.005mol/L H2SO4
Heavy Metals (Pb): 2.0g, (1), pH=7, ref: 2.0ml of Pb Std. (0.01mg/ml)
Arsenic (As2O3): 2.0g, (1), ref: 2.0ml of As2O3 Std.
Other Amino Acids: Test Sample: 10μg, A-1-a
Loss on Drying: In vacuum, P2O5, at room temperature for 20 hous.
Residue on Ignition (Sulfated): AJI Test 13
Assay: Dried sample, 250ml, 0.05mol/L I2 1ml=15.762mg C3H7NO2S·HCl
Other Amino Acids: Dissolve 200mg of the sample in 2% N-ethyl-maleimide aqueous solution to make 100ml and allow to stand for 30 minutes and then proceed as directed for procedure under AJI TEST 9.