Measurement of the NO metabolites, nitrite and nitrate, in human biological fluids by GC–MS

In this article we critically review the development and application of gas chromatography–mass spectrometry (GC–MS) techniques to the measurement of the nitric oxide (NO) metabolites, nitrite and nitrate, in human biological fluids. Our focus is on the issue of the fitness of any analytical strategy to its intended purpose and the validity of the analytical results generated. The accuracy, precision, recovery, selectivity and sensitivity of the various methods are evaluated and the potential pitfalls, both specific to the methods, and general to the area, are considered. Several examples of the applications of these techniques to clinical investigations of NO physiology are also critically evaluated.