Analytical Biochemistry 1990-09-01

A spectrophotometric method for the estimation of polymer-supported sulfhydryl groups.

P Sharma, S Sathyanarayana, P Kumar, K C Gupta

Index: Anal. Biochem. 189(2) , 173-7, (1990)

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Abstract

A sensitive and simple method is described for the quantitative determination of free sulfhydryl (-SH) groups on polymer supports. The method includes the reaction of 4,4'-dimethoxytrityloxy-S-(2-thio-5-nitropyridyl)-2-mercapto ethane (DTNPME) with polymer-supported sulfhydryl groups. After removal of excess reagent through washing, a weighed quantity of the polymer support is treated with perchloric acid to release the 4,4'-dimethoxytrityl cation from the polymer support into the solution. The dimethoxytrityl cation (lambda max = 498 nm, epsilon 498 = 70,000/M) is then quantified spectrophotometrically. A comparative study of the reagent DTNPME with 2,2'-dithiobis(5-nitropyridine) is also described.