A spectroscopic method for the quantitative determination of NO in aqu
eous solution is presented. The method is based on the uv absorbance o
f nitrosothiols, coupled with the inner filter effect. A threshold of
5.10(-7) M with a wide dynamic range of 5.10(-7)-10(-4) M are obtained
. This method enables measurements in brain homogenates. Ultimately, s
ince this method is immune to electrical perturbances, it will be appl
ied at the tip of an optical fiber for in situ monitoring of NO or glu
tathione in brain and blood vessels. (C) 1994 Academic Press,Inc.