Ultra-trace determination of S-nitrosothiols in blood samples by spectrofluorimetry with 8-(3′,4′-diaminophenyl)-difluoroboradiaza-s-indacene

Increasing evidence suggests that S-nitrosothiols (RSNO) may represent naturally occurring nitric oxide (NO) surrogates and function as intermediates in NO metabolism. In this work, a simple, sensitive, and selective micromethod is developed and validated for quantification of RSNO. A fluorescent probe 8-(3′,4′-diaminophenyl)-difluoroboradiaza-s-indacence (DABODIPY) is firstly used to label RSNO. The derivatization reaction is performed in aqueous medium at 30 °C for 15 min in the presence of 6 × 10−5 mol L−1 Hg2+ and the derivative is detected by fluorescence at λex/λem = 500/510 nm. A linear function of concentration in the range of (2.0-600.0) × 10−8 mol L−1 is observed with a correlation coefficient of 0.9992 and detection limit of 1.2 × 10−9 mol L−1 (S/N = 3). This technique has been successfully applied to quantify RSNO in some human blood samples including healthy persons and patients suffering from cardiovascular diseases.