Determination of 73 volatile organic compounds in environmental water samples by purge-and-trap combined with two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC TOFMS)

A method based on purge and trap combined with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC TOFMS) was developed in this paper for the determination of 73 volatile organic compounds in environmental water. The influences of modulation periods and purge times on different levels were studied on the separation and sensitivity of the method while deconvolution technique by characteristic ions was applied for the qualitative identification of compounds that were not completely separated by chromatography. The two-dimensional coordinate projection method was proposed to character the class distribution of two-dimensional fingerprint spectra with one-dimensional coordinates. The impacts of solvent chromatogram on target compounds were also discussed. The method performances were evaluated and confirmed including the method detection limits, precision and accuracy. The results revealed that accurate identification of 73 compounds was achieved with complete separation of chromatographic peaks for 67 compounds. The method detection limits of 65 compounds were less than 0.20 μg·L−1, and the others were in the range of 0.20—1.50 μg·L−1. This method has been successfully applied in the investigation of volatile organic compounds in various types of environmental water samples such as surface water, ground water, sewage and landfill leachate.