Development of thin-film solid-phase microextraction coating and method for determination of artificial sweeteners in surface waters

A semi-automated and sensitive method was developed for simultaneous determination of the six most consumed artificial sweeteners (AS) in surface waters using thin-film solid-phase microextraction (TF-SPME) and high-performance liquid chromatography (HPLC). A triple quadrupole mass spectrometer and an electrospray ionization source (ESI-MS) run in negative ionization and multiple reaction monitoring modes were employed for instrumental analysis. The TF-SPME method was optimized for the extraction phase, sample pH, desorption solvent, extraction time, and desorption time. In-house-synthetized-hydrophilic-lipophilic balance weak anion exchange (HLB-WAX) particles imbedded within a polyacrylonitrile (PAN) binder were selected as the extraction phase for the thin-film coating due to their cost-effectiveness and enhanced sensitivity for artificial sweeteners. Suitable analytical parameters that include linearity (R-2 > 0.9914), recovery > 80%, inter, and intra-reproducibility less than 18% were obtained for the AS compounds studied. The developed method estimated limits of detection (LODs) ranging from 0.004 to 0.038 ng mL(-1) The SPME method was successfully applied for the determination of ultra-trace levels of AS in water samples collected from Grand River (Ontario, Canada), downstream of three municipal wastewater treatment plants (WWTPs). Concentrations ranging from 0.03 to 20.3 ng mL(-1) were found for the AS compounds studied.