S-(Carboxymethyl)-L-Cysteine CAS 638-23-3 (Carbocisteine) Assay 98.5~101.0%

S-(Carboxymethyl)-L-Cysteine, when dried, contains not less than 98.5 percent and not more than 101.0 percent of S-(Carboxymethyl)-L-Cysteine (C5H9NO4S).
Description: White crystals or crystalline powder, slightly acid taste.
Very slight soluble in water, practically insoluble in ethanol and in glacial acetic acid and in ether. Dissolves in dilute hydrochloric acid and in sodium hydroxide T.S..
Solubility (H2O, g/100g): 0.13 (20℃)
Identification: Compare the infrared absorption spectrum of the sample with that of the standard by potassium bromide disc method.
Specific Rotation [α]20/D: Dried sample, C=10, pH6.0. After drying the sample, take about 5g of the sample. accurately weighed, dissolve in 20ml of water and sodium hydroxide solution (13→100). After pH adjust to 6.0 with 1mol/L or 0.1mol/L hydrochloric acid T.S., then add water to accurately 50ml.
State of Solution (Transmittance): 1.0g in 10ml of 1mol/L NaOH, spectrophotometer, 430nm, 10mm cell thickness.
Chloride (Cl): 0.36g, A-2, ref: 0.40ml of 0.01mol/L HCl
Ammonium (NH4): A-1
Sulfate (SO4): 1.2g, (2), ref: 0.50ml of 0.005mol/L H2SO4
Iron (Fe): 0.5g, (2), ref: 1.5ml of Iron Std. (0.01mg/ml)
Heavy Metals (Pb): 2.0g, (2), ref: 2.0ml of Pb Std. (0.01mg/ml)
Arsenic (As2O3): 2.0g, (3), ref: 2.0ml of As2O3 Std.
Other Amino Acids: 0.2mol/L NaOH, test Sample: 75μg, B-2-a control; S-(Carboxymethyl)-L-Cysteine 0.15μg. After each of the solutions is spotted on the plate, the plate is developed at once
Loss on Drying: at 105℃ for 3 hours
Residue on Ignition (Sulfated): AJI Test 13
Assay: Dried sample, 180mg, 0.1mol/L HCLO4 1ml=17.920mg C5H9NO4S. Dissolve about 180mg of the sample, previously dried and accurately weighed, in 3ml of formic acid, add exactly 15ml of 0.1mol/L perchloric acid, and 50ml of glacial acetic acid, and titrate the excess perchloric acid with 0.1mol/L sodium acetate, determing the endpoint potentiometrically. Perform a blank determination, and make necessary correction. Each ml of 0.1mol/L perchloric acid is equivalent to 17.920mg of C5H9NO4S.
pH: 1.0g in 10ml (Saturated aqueous solution)
Recommended storage limit and condition: Preseved tight containers at controlled room temperature (2 years).