Development of a solid-phase microextraction–gas chromatography–tandem mass spectrometry method for the analysis of chlorinated toluenes in environmental waters

In the present work, a simple and fast methodology has been developed for the analysis of chlorotoluenes in water samples using solid-phase microextraction (SPME) coupled to gas chromatography–tandem mass spectrometry (GC/MS/MS). A multifactorial experimental design strategy was used for studying the influence on extraction yield of factors such as fiber coating, extraction mode, temperature, and addition of sodium chloride. Quantitative recoveries (≥84%) and satisfactory precision (relative standard deviations (RSD) ≤ 12%) have been obtained. Limits of detection (LODs) in the sub-picogram per litre level from 0.030 to 0.330 were achieved for all analyzed compounds. Linearity was studied in a wide range of concentrations and an analysis of variance with a lack-of-fit test was run to validate the calibration data. Extraction time profiles were also studied, showing that most of chlorotoluenes reached the equilibrium or were close to it. Finally, the applicability of the proposed method has been demonstrated for real samples including river and sewage water samples. Since no matrix effects were observed, quantification could readily be carried out by external calibration with ultrapure water standards.