[Standardization of a method of determining the thiolic-SH groups in human blood due to kinetic considerations]

Since the reaction of colorimetric titration of the sulphydril groups in human serum with the Ellman method, useful, besides, to follow the course of rheumatic diseases, occurs at 100% only after quite long time, for routine analysis it's necessary to keep to a standard degree of reaction, that is to take the absorbance always after the same time. Referring instead to the plateau of the titration curve it's necessary to put oneself in the conditions to reach the 100% of reaction in a short time. This is possible only by diluting the serum strongly, to the detriment of the precision of the analysis. The best conditions we found for quick and sufficiently precise clinical analysis are obtained by absorbances included between 0,15 and 0,30 u.A., which are reached with a calculated dilution of serum.