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 4mL of processed sample followed by elution with 40μL 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, 0.025-2.5μg/L for chlorpyriphos and 0.25-25μg/L for the other tested compounds and LODs between 0.025μg/L and 2.5μg/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).