Development of a headspace-gas chromatography (HS-GC-PID-FID) method for thedetermination of VOCs in environmental aqueous matrices: Optimization,verification and elimination of matrix effect and VOC distribution on the Fortaleza Coast, Brazil

Abstract

An analytical protocol combining a headspace technique with gas chromatography and detection byphotoionization detector andflame ionization detector (HS-GC-PID-FID) was developed. This procedure wasused to measure volatile organic compounds (VOCs) in environmental aqueous matrices and was applied indetermination of VOCs on the coast of Fortaleza, Brazil. At optimum operating conditions, analyticalfiguresof merit such as linearity (Rranged from 0.9983 to 0.9993), repeatability (5.62 to 9.63% and 0.02 to 0.19% forthe quantitative and qualitative analyses, respectively), detection limits (0.22 to 7.48μgL−1) and sensibilitywere estimated. This protocol favors a fast sampling/sample preparation (in situ), minimizes the use oflaboratory material, eliminates the matrix effect from environmental samples, and can be applied to river,estuarine and oceanic waters. The advantage of detectors in series is that a low sensitivity in detection in one iscompensated by the other. Toluene was the most abundant VOC in the studied area, with an averageconcentration of 1.63μgL−1. It was followed byo-xylene (1.15μgL−1), trichloroethene (1.08μgL−1), benzene(0.86μgL−1), ethylbenzene (0.74μgL−1), carbon tetrachloride (0.55μgL−1),m/p-xylene (0.48μgL−1)andtetrachloroethene (0.46μgL−1), compounds which are very commonly detected in urban runoff from mostcities. The results of the VOC distribution showed that port activity was not the main source of VOCs along theFortaleza Coast, but that the contribution from urban runoff seemed more significant.