Since its introduction by Lovelock, about 20 years ago, the electron-capture detector
(ECD) has had an enormous impact in trace analysis by gas chromatography. Nowhere is
this more apparent than in environmental and biomedical studies, where the detector was
often foremost in forging the link between minute concentrations of biologically active
substances and their physiological responses. Although new detectors have appeared since
the introduction of the ECD, none has succeeded in replacing it in many of its original
applications. Its use remains dominant in such areas as the study of the concentration
and fate of pesticides in the environment, the impact of fluorocarbon aerosol propellants
on stratospheric ozone concentrations, the health risk from toxic chemicals in the
workplace and the vicinity of disposal sites, the therapeutic monitoring and metabolic
fate of drugs in man and for the determination of biologically active molecules such as
hormones in physiological fluids.