Hair sulfur amino acid analysis.

This overview emphasizes present aspects of sulfur-containing amino acids in hair. A selection of analytical procedures to determine cystine, cysteine, S-sulfocysteine, cystine oxide, cysteic acid, lanthionine and lysinoalanine are presented. The methods relate to intact hair or partial and total hydrolysates and comprise chromatography, titration, colorimetry, polarography and spectroscopy. For the analysis of cysteine, cystine and cystine oxides, polarography and spectroscopy are the methods of choice. Cysteic acid, lanthionine and lysinoalanine are analysed by means of ion-exchange chromatography (Spackman et al., 1958) after total hydrolysis.