Detection of S-Nitrosothiols and other nitric oxide derivatives by photolysis-chemiluminescence spectrometry

We have developed a method for the detection of biologically relevant derivatives of NO . that couples photolysis to chemiluminescence. S-Nitrosothiols, N-nitroso-L-tryptophan, and iron-nitrosyl derivatives can all be detected by this methodology, and these derivatives can be distinguished from free NO . by making measurements with and without photolysis. The limits of detection of this system are in the 10 nM range, with an intraassay variability of less than 2% and an interassay variability of less than 1.5%. The use of cutoff filters and alterations in pH and flow rate through the photolysis cell provide additional useful parameters with which to characterize specific NO . derivatives based on their intrinsic stability. This methodology is a useful addition to the growing armamentarium of techniques used to characterize the biochemistry and metabolism of NO .. (C) 1997 Academic Press.