A high-performance ionic liquid-based microextraction (ILBME) method for the trace determination of paroxetine as a pharmaceutical pollutant in environmental and biological samples.

A high-performance ionic liquid-based microextraction technique utilizing a task-specific imidazolium-based ionic liquid was employed for the analysis of paroxetine as a pharmaceutical pollutant at trace levels in some real environmental and biological samples. An ionic liquid, 3-(2-hydroxy-4-(isopropylamino)butyl)-1-methylimidazolium chloride, abbreviated to [Hibmim][Cl], was synthesized with a yield of 90.4%. Its physical properties were determined and characterized using FTIR, HNMR, CNMR, and CHNO techniques. The ionic liquid was then used for preconcentration prior to the determination of paroxetine in water and urine samples. Specifically, the ionic liquid served as both the extractor and the extracting phase, demonstrating high efficiency in extracting paroxetine from real samples. Density functional theory (DFT) studies, as well as UV-Vis and FTIR analyses indicated that the ionic liquid could successfully form a chelate with paroxetine via hydrogen bonds. To confirm the method efficacy for analyzing real samples, the figures of merit and parameters affecting the microextraction procedure were assessed and optimized. Under optimal conditions, the limit of detection, limit of quantification, linear dynamic range, intra-day and inter-day relative standard deviations, preconcentration factor, and enhancement/enrichment factor were determined to be 0.42 μg L^-1, 1.41 μg L^-1, 5.0-60.0 μg L^-1, 2.58%, 3.83%, 197.3, and 193.3, respectively. The maximum yield of paroxetine extraction under optimal conditions was 98.8%. Finally, to evaluate the method validity, a standard addition procedure was used, yielding satisfactory recovery values ranging from 98.7% to 101.2%.