Quantitative determination of functional thiol groups on intact cell surfaces by resonance Raman spectroscopy

The sensitivity and selectivity of resonance Raman spectroscopy, combined with electronic spectroscopy, has been used to develop a method to quantify the membrane thiol population in situ in viable erythrocytes. This technique is based on the thiol-disulfide reaction of Ellman's reagent (5,5'-dithio-bis-2-nitrobenzoic acid). It has the advantage that continuous monitoring of lysis is simple and a correction can be made for any interference resulting from lysis. In addition, the extent of reaction can be expressed as a ratio of the reagent signal, providing an internal calibrant.