A simple method for the trace determination of methanol, ethanol, acetone and pentane in human breath and in the ambient air by preconcentration on solid sorbents followed by gas chromatography.

A simple technique has been developed for preconcentration of gaseous trace organic compounds on solid sorbents, followed by gas chromatography. The sorbent is packed in a cartridge from a syringe needle placed in the gas chromatographic injector and the analytes previously adsorbed are thermally desorbed at the injector temperature and then directly swept by the carrier gas into the column. The system has been tested for a charcoal-based adsorbent and silica gel, with pentane, methanol, ethanol and acetone as the model analytes. The procedure is rapid, the detection limits vary from a few nmol l(-1) to values below 0.1 nmol l(-1) (i.e., a few ppb), the linear dynamic range amounts to at least five concentration decades and a typical relative standard deviation is 10% at the nmol l(-1) concentrations. It has been shown that the method is readily applicable to determination of instantaneous concentrations of the analytes in natural and industrial atmosphere and to their monitoring in human breath which is important for medical and hygienic practice. In general, the procedure is applicable to low-molecular volatile organic compounds.