QUANTITATIVE TRACE ANALYSIS BY COMBINED CHROMATOGRAPHY AND MASS-SPECTROMETRY USING EXTERNAL AND INTERNAL STANDARDS

This review covers established methods for trace organic analysis by quantitative chromatography. Although these methods are of more general applicability, they are widely used in practice with mass spectrometric detection. In the important class of methods employing surrogate internal standards (usually isotopically labelled versions of the target analytes), mass spectrometry is almost always obligatory in view of the inability to chromatographically resolve such a standard from the analyte in all but a few exceptional cases. The relative strengths and weaknesses of the methods are compared, and distinctions are drawn between 'best' methods for different circumstances, e.g., quality control of pharmaceutical preparations compared with analyses of environmental samples.