IN-SITU NITRIC-OXIDE (NO) MEASUREMENT BY MODIFIED ELECTRODES - NO LABILIZED BY PHOTOLYSIS OF METAL NITROSYL COMPLEXES

Described are studies directed at refining quantitative analysis of ni tric oxide in solution using electrochemical techniques. The fabricati on and behavior of several sensors based on modified carbon-based elec trodes are reported. This technique has been used to resolve the vexin g problem of determining the stoichiometry of the photochemical decomp osition of the known antihypertension agent sodium nitroprusside, Na-2 [Fe(CN)(5)NO], as well as of two other metal nitrosyl complexes of bio logical interest, Roussin's black salt, NH4[Fe4S3(NO)(7)], and Roussin 's red salt, Na-2[Fe2S2(NO)(4)], in aqueous solutions. In this manner it was shown that the molar ratios of nitric oxide produced per starti ng complex photochemically decomposed were 0.95 +/- 0.03, 5.9 +/- 0.2, and 0.50 +/- 0.02 for Na-2[Fe(CN)(5)NO], NH4[Fe4S3(NO)(7)], and Na-2[ Fe2S2(NO)(4)], respectively. (C) 1997 Academic Press.