| abstract |
A method of direct analysis of an analyte in keratinized structures, for example the hair and the nails, consists in preparing a mixture containing an activating compound with low redox potential such as dithiothreitol or dithioerythritol, an enzyme suitable for digestion keratin structure, a sample of the keratin structure and a biological detergent which facilitates digestion of the keratinized structure at a relatively low pH, for example between 6.2 and 8; the enzyme is then allowed to digest the sample of the keratin structure, and the digestion solution is subjected to analysis, preferably by radio immuno-analysis in order to determine the identity and the amount of the analyte in the keratin structure sample. To speed up the process, copper sulphate can be added to the mixture after degradation of the keratin sample. The enzyme may be a peptidase, an endopeptidase or a proteinase, the enzymes preferably used in the invention being papain, chemiopapain and proteinase K. Preferred biological detergents include betaine, sulfo-betaine, alkyl glucosides and bile acids. |