Determination of cyclophosphamide and ifosphamide in urine at trace levels by gas chromatography/tandem mass spectrometry.

A specific and sensitive method based on gas chromatography/tandem mass spectrometry with on-column injection was developed to quantify simultaneously cyclophosphamide and ifosphamide in urine by using trophosphamide as an internal standard. The urine samples were extracted with diethyl ether and derivatization was performed with heptafluorobutyric anhydride. The detection limits of cyclophosphamide and ifosphamide in urine samples were 0.1 and 0.5 ng ml(-1), respectively, with a signal-to-noise ratio of 3 : 1. The sensitivity, the specificity and the low cost of the instrumentation involved make this method suitable for economical analysis on a large scale, such as for the biological monitoring of occupational exposure to cyclophosphamide and ifosphamide in production plants and in hospitals during their pharmacological use. Copyright 1999 John Wiley & Sons, Ltd.