Multiresidue analysis of organic pollutants by in-tube solid phase microextraction coupled to ultra-high performance liquid chromatography–electrospray-tandem mass spectrometry

In this work, in-tube solid phase microextraction (IT-SPME) coupling with ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) multiresidue analytical method has been proposed for the first time for on-line enrichment of 9 analytes included in Water Frame Directive 2000/60/EC (WFD). The device was equipped with a GC TRB-5 capillary column, used as pre-concentration loop, and two conventional six-port injection valves. Water sample and desorption solvent volumes were tested. The optimum conditions were 4 mL of processed sample followed by elution with 40 μL of methanol. The analytes were detected with a mass spectrometer after being ionized positively using an electrospray ionization (ESI) source. The method presents good linearity over the range assayed, 0.025–2.5 μg/L for chlorpyriphos and 0.25–25 μg/L for the other tested compounds and LODs between 0.025 μg/L and 2.5 μg/L. Enrichment factors ranged from 2.5 to 10. Intra and inter-day variation coefficients were <26 and 31.6% respectively. Once validated, the method was applied to several water samples from different sources demonstrating that it achieves the on-line enrichment of the analytes with the advantage of minimum sample manipulation, and the identification and quantification of some organic pollutants in water samples in the range of low parts-per-billion. The method provided similar analytical characteristics as those obtained in the established couple IT-SPME–Capillary Liquid Chromatography (CapLC).