Fast atom bombardment mass spectrometry of steroid sulphates: qualitative and quantitative analyses

Negative ion mass spectra obtained by fast atom bombardment of glycerol solutions of steroid sulphates include the steroid sulphate anion as the single prominent feature. High sensitivity is achieved, with full spectra obtained for samples of less than 15 ng. Differentiation of the isomeric steroids, dehydroepiandrosterone sulphate and testosterone sulphate, is made by comparison of the products of fragmentation of metastable ions. Analyses of biological extracts suffer from poorly-understood matrix effects which may cause partial or complete suppression of the signal attributable to steroid sulphates. Use of an immunoadsorption extraction technique, however, has permitted the detection and approximate quantification (using a (2H2) analogue as internal standard) of dehydroepiandrosterone sulphate in blood plasma. Interference from glycerol background is avoided by preparation of the pentafluorobenzyloxime derivatives.