Analysis of gasoline contaminated water samples by means of dopant-assisted atmospheric pressure photoionization differential ion mobility spectrometry

Abstract

In this study the influence of aromatic dopant benzene on the sensitivity of GC-APPI-DMS to gasoline related aromatic compounds was investigated. This influence was investigated on example of four gasolin related fingerprints (toluene, ethylbenzene, o-xylene, and 1,2,4-trimethylbenzene), which were found in high relative abundance in the water-soluble gasoline fraction. The analysis of calibration curves slopes demonstrats that the GC-APPI-DMS sensitivity to gasoline fingerprints can be improved by up to seven times when benzene concentration in nitrogen carrier gas is less than 10 ppmv/v. The estimated detection limits (S/N = 3) for the analyzed in this study compounds were found to be within the range of 33–105 μg L−1 at benzene concentration in the carrier gas of 2.27 ppmv/v (10 μL injection volume). These limits of detection may be reduced (at the cost of lower resolution) using the larger injection volumes. For example, increase of injection volume to 100 μL at benzene concentration in the carrier gas of 2.27 ppmv/v leads to reduction of LOD values for toluene, ethylbenzene, and o-xylene to 11.1, 13.3, and 5.3 μg L−1, respectively.