Sampling and analysis of volatile organic compounds in estuarine air by gas chromatography and mass spectrometry

Abstract

The spatial and temporal distribution of volatile organic compounds (VOCs) in air samples taken beside a semi-industrialised estuary was intensively studied over a two-year period. Samples were collected by trapping VOCs onto multi-bed traps packed with graphitised carbon black sorbents capable of selectively trapping a wide range of volatile substances. Samples were then analysed using an automated thermal desorption technique followed by capillary column gas chromatography with simultaneous detection of volatile eluates using flame ionisation and ion trap detectors. The lower limit of detection was circa 0.5 ng m −3 for most compounds. The major groups of organic compounds collected were C 1–C 4 alkylbenzenes, alkanes and alkenes, and chlorinated solvents. Terpenes were also found in high concentrations in forested areas which fringe the estuary. Significant seasonal differences in the distribution and concentration of VOCs occur between summer and winter. A case study from the VOCs research in and around the Southampton Water estuary on the central southern coastline of England is presented as an example of the method application.