Analysis of volatiles in water using headspace solid-phase microcolumn extraction

A rapid solvent-free sample preparation method is presented in which volatilized organic substances are extracted via a solid-phase microcolumn mounted on a gas-tight syringe by the aspiration of an appropriate volume of headspace (tens of millilitres) of the sample under investigation. The microcolumn with the analytes concentrated on an adsorbent material is then transferred to the analytical instrument for desorption and analysis. The instrumental set-up consists of a Twister desorption unit (Gerstel) mounted on an Agilent 6890 GC system equipped with a CIS 4 programmed temperature vaporiser injector and coupled with an Agilent 5973 MS system. The instrumentation is slightly modified in comparison with the analysis made with a twister (stir bar coated with a layer of polydimethylsiloxane) after stir bar sorptive extraction and, thus, its utilization has been extended. For volatiles in water, the method is applicable to the qualitative screening at the microg/l to sub-microg/l level and to the quantitative determination at the ng/l level.