Polypyrrole-polyaniline nanorods assisted electromembrane extraction of phenolphthalein from herbal slimming products prior to its determination by the liquid chromatography method

Abstract

Herein, polypyrrole-polyaniline nanorods (PPy-PANI NRs) were synthesized via oxidative polymerization and subsequently were used in electromembrane extraction of phenolphthalein from herbal slimming products. The copolymer was added to the supported liquid membrane to enhance the extraction efficiency of phenolphthalein (PP), and then the analyte was determined by a liquid chromatography-ultraviolet detection system. This is the first report on the application of PPy-PANI NRs as an additive in the electromembrane extraction method. The PP can interact with the PPy-PANI NRs material via interactions such as ion exchange, electrostatics, π-π, and hydrogen bonding. Accordingly, an enhancment in extraction performance was observed in the presence of PPy-PANI NRs as the SLM modifier. The optimized extraction conditions were: donor phase pH, 8.2; acceptor phase pH, 12.0; extraction time, 14 min; voltage, 30 V; stirring rate, 750 rpm; PPy-PANI NRs concentration in the SLM, 1.0 mg mL−1; and 1-octanol as the extraction solvent. A wide linear range and low detection limit equal to 3.0–2000, and 1.0 μg L−1 were obtained, respectively. Besides, the excellent clean-up was attended, which is a great advantage over the more sample preparation methods. Finally, the new method was successfully used to determine PP in slimming products of Iranian markets, and satisfactory results (5.5–8.5 % RSDs; relative recovery, 80–110 %) were obtained.