Emulsion-Based Liquid-Phase Microextraction Using Rhamnolipid Bioaggregates for Determination of Paracetamol in Human Urine Samples and Tablet Formulation Followed by HPLC Analysis

Abstract

Abstract This work describes a simple, sensitive, and environmentally friendly analytical technique for the determination of paracetamol in human urine samples and tablet formulation. The proposed technique for the extraction and enrichment of the paracetamol is based on the use of rhamnolipid biosurfactants in emulsion-based liquid-phase microextraction. The separation mechanism of paracetamol is based on the emulsion formation of the biosurfactant-rich phase. First, a bioemulsion solution (colloidal phase) was formed and then the analyte was isolated onto the non-aqueous phase. The second step consists of back extraction of the analyte into an aqueous acceptor phase. Finally, the aqueous acceptor phase was withdrawn using a microsyringe and injected into a liquid chromatography instrument for quantitative analysis. The ability of rhamnolipid biosurfactants to form a stable colloidal phase with regions of different polarities can lead to extraction analyte using Van der Waals interactions. Owing to the biodegradability of the rhamnolipid biosurfactants, the proposed technique is environmentally friendly because it has led to the omission of chemical surfactants. Several influencer factors on extraction efficiency including the amount of rhamnolipid biosurfactant, methanol volume, pH, extraction time, ionic strength, and centrifugation time were investigated and optimized. Under optimal conditions, the enrichment factor for the paracetamol was 160. Also, good linearity was obtained in the range 34–100 µg L− 1, with coefficients of determination (r2) ˃ 0.993.