L-цистин

Химические свойства

A white or almost white, crystalline powder, practically insoluble in water and in alcohol.

Использование

L-Cystine is a non-essential amino acid for human development. L-Cystine is formed by the dimerization of two cysteines through the sulfur.

Общее описание

This Standard Reference Material (SRM) is intended primarily for use in validating microchemical procedures for the determination of carbon, hydrogen, nitrogen, and sulfur in organic matter. SRM 143d is pure crystalline cystine supplied in a 2 g unit size. For more information, please refer to the SDS and COA.

SRM 143D_cert SRM 143D _SDS

Профиль безопасности

Low toxicity by ingestion. When heated to decomposition it emits toxic fumes of PO, and SOx

Методы очистки

Cystine disulfoxide impurity is removed by treating an aqueous suspension with H2S. The cystine is filtered off, washed with distilled water and dried at 100o under a vacuum over P2O5. Crystallise it by dissolving in 1.5M HCl, then adjusting to neutral pH with ammonia. Likely impurities are D-cystine, meso-cystine and tyrosine. Also purify it by dissolving it in 10% NH3 and adding gradually dilute AcOH until the point of precipitation and cooling slowly [Dughton & Harrison Acta Cryst 12 396, 402 1959.] Alternatively dissolve it in 6N NH4OH and evaporate it at room temperature for crystallisation to occur. [Chaney & Steinrauf Acta Cryst 30 711 1974, Beilstein 4 IV 3155.]