A method for the determination of the mercaptan groups in intact, that is, nonhydrolyzed, human hair has been developed. The procedure is based upon the titration with silver nitrate of the iodide ion generated in the reaction between the sulfhydryl groups in the hair and iodoacetamide. The standard error of the method is of the order of 0.010 mequivs mercaptan/g hair. © 1960, All rights reserved.
Stein, H. H., & Guarnaccio, J. (1960). The determination of sulfhydryl groups in reduced hair keratin. Analytica Chimica Acta, 23, 89–97. https://doi.org/10.1016/S0003-2670(60)80019-0