Direct hollow fibre liquid phase membrane extraction and LC-MS determination of selective serotonin reuptake inhibitors in fish tissue

Abstract: Selective serotonin reuptake inhibitors (SSRIs) have been found in waste water treatment plant effluents and surface water at detectable concentrations. Although the medical effects and side effects of pharmaceuticals and personal care products are investigated through safety and toxicology studies the potential environmental impacts are less studied, and information concerning ecotoxicological risks and the distribution in sludge, surface water and water living organisms is rather scarce. In this thesis, sertraline (SER), fluoxetine (FLU) and its N-desmethyl metabolite norfluoxetine (norFLU) were chosen as model substances to develop a method for detection. Fish was chosen as the model matrix because fish is a top predator with possible high analyte concentrations because of biomagnification. Hollow fibre liquid-phase membrane extraction (HF-LPME) was used as the extraction, clean-up and enrichment technique and LC-MS was used to detect the SSRIs in fish muscle tissue. This analytical method showed enrichment factors ranging 1500-1800 for fish samples and 3000-6300 for water samples. The R2-values of the linearity were 0.936, 0.990, 0.966 for norFLU, FLU and SER, respectively. The detection limits of the method for norFLU, FLU and SER were in the range of 130-280 ng L-1. The method was successfully applied to detect the analytes in exposed crucian carp; 1.7 μg g-1 FLU and 2.8 μg g-1 SER were found after exposure to a 51 μg L-1-mixture for 3 days. The FLU metabolite norFLU was not added in the exposure solution and it was not formed in detectable concentrations during the exposure. In unexposed crucian carp, none of the analytes were detected. The developed analytical method might be extended to estimate the distribution or the fate of norFLU, FLU and SER in other biota or human beings.