Determination of dehydroepiandrosterone sulfate in human plasma by gas chromatography/mass spectrometry using a deuterated internal standard: a method suitable for routine clinical use.

A capillary gas chromatographic-mass spectrometric method for the determination of dehydroepiandrosterone sulfate (DHEA-S) in human plasma is described. [7,7-2H2]DHEA-S is used as internal standard. After desulfation by methanolysis, heptafluorobutyryl derivatives are prepared, and selected ion monitoring of characteristic fragment ions--m/z 270 for DHEA and m/z 272 for [7,7-2H2]DHEA--carried out. Requiring small amounts of plasma, the rapid, convenient work-up and the application of bench-top GC/MS instrumentation proved our method to be suited for routine clinical use in adults and children. The method needs no complex corrections for isotope contributions and provides good accuracy and precision. Comparative values of samples assayed by our GC/MS procedure and by a direct RIA indicated that the RIA overestimates the true concentration.