The headspace method and purge & trap method are used for the analysis of volatile organic compounds (VOCs) in soil, with the method utilized dependent on the sample concentration. The headspace method features easy operation and good repeatability; it allows use of an autosampler; and produces little carryover (contamination of analysis instrument by high-concentration substances). The purge & trap method uses trapping agents to concentrate the sample, and is able to measure low-concentration samples at a sensitivity 10 to 100 times higher than the headspace method.
An example of analysis using the headspace method is shown below.

The headspace method and purge & trap method are used for the analysis of volatile organic compounds

Gas Chromatograph Mass Spectrometer

Gas Chromatograph Mass Spectrometer

This analysis instrument is widely used for the qualitative and quantitative analysis of chemical substances. The column and ionization method are selected to suit the analysis target.