In human organism, the gaseous radical molecule nitric oxide (NO) is produced in various cells from l-arginine by the catalytic action of NO synthases (NOS). The metabolic fate of NO includes oxidation to nitrate by oxyhaemoglobin in red blood cells and autoxidation in haemoglobin-free media to nitrite. Nitrate and nitrite circulate in blood and are excreted in urine. The concentration of these NO metabolites in the circulation and in the urine can be used to measure NO synthesis in vivo under standardized low-nitrate diet. Circulating nitrite reflects consitutive endothelial NOS activity, whereas excretory nitrate indicates systemic NO production. Today, nitrite and nitrate can be measured in plasma, serum and urine of humans by various analytical methods based on different analytical principles, such as colorimetry, spectrophotometry, fluorescence, chemiluminescence, gas and liquid chromatography, electrophoresis and mass spectrometry. The aim of the present article is to give an overview of the most si...

Methods of quantitative analysis of the nitric oxide metabolites nitrite and nitrate in human biological fluids.

Derivatisation reactions in the chromatographic analysis of chemical warfare agents and their degradation products.

Quantification of nitrite and nitrate in human urine and plasma as pentafluorobenzyl derivatives by gas chromatography-mass spectrometry using their 15N-labelled analogs.

Wu Hsin-Lung

Papers

Gas chromatographic determination of inorganic anions as pentafluorobenzyl derivatives