Quantifying Small Molecules by Mass Spectrometry

The use of a mass spectrometer in quantitative analysis exploits its exquisite selectivity and sensitivity as a detector, allowing a signal to be ascribed to a particular chemical entity with high certainty, even when present in a sample at a low concentration. There are, however, some special considerations that are necessary when a mass spectrometer is used as a quantitative tool. In this instalment, we discuss the general precepts of quantitative analysis, as well as the concept of "fitness for purpose", in the context of those considerations.