Determination of nitrate in blood by gas chromatography and gas chromatography-mass spectrometry

We devised a sensitive and simple method for determining nitrate in whole b lood, using an extractive alkylation technique. Nitrate in whole blood was reduced to nitrite by hydrazine sulfate in the presence of Cu2+ and Zn2+ as catalysts, and alkylated with pentafluorobenzyl bromide using tetradecyldi methylbenzylammonium chloride as the phase-transfer catalyst. The obtained derivative was analyzed qualitatively by gas chromatography-mass spectromet ry and quantitatively by gas chromatography with electron-capture detection . The detection limit of nitrate in whole blood was 0.01 mM. The calibratio n curve was linear over the concentration range from 0.02 to 1.0 mM for nit rate in whole blood. The accuracy and precision of the method were evaluate d and the relative standard deviations were found to be within 10%. Using t his method, the blood nitrate levels of two victims who committed suicide b y inhaling automobile exhaust gas were determined. (C) 2000 Elsevier Scienc e B.V. All rights reserved.