Development of a screening method for the determination of PCBs in water using QuEChERS extraction and gas chromatography-triple quadrupole mass spectrometry

A new method has been developed and validated for the simultaneous analysis of 11 polychlorinated biphenyls (PCBs), in water samples at trace levels by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QqQ-MS/MS). Water samples were extracted by the QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method. The QqQ analyzer acquired data in multiple reactions monitoring (MRM), permitting both quantification and confirmation in a single injection with a running time reduced up to 11.0 min. The effect of matrix interferences in extracts on analyte quantification and the identification of PCBs in water samples was deeply studied. The results showed that PCBs were prone to strong matrix interactions in water samples, and the quantification and identification of PCBs were highly affected by a matrix enhancement effect. To evaluate the performance of the method, validation experiments were carried out on water samples at three spiking levels (1.6, 8.0, 40.0 μg L(-1)). Recovery was in the range of 95 - 109% at 1.6 μg L(-1), 90 - 95% at 8.0 μg L(-1) and 97 - 102% at 40.0 μg L(-1), respectively. Precision values expressed as relative standard deviation (RSD) were lower than 15%. Linearity in the range of 0.5 - 50.0 μg L(-1) provided determination coefficients (R(2)) higher than 0.999 for all compounds. The limits of detection (LODs) for PCBs were ≤0.1 μg L(-1) and the limits of quantification (LOQs) ranged from 0.04 to 0.3 μg L(-1). The applicability of the proposed method to detect and quantify PCBs has been demonstrated in analyse of 15 real samples.