Electrically assisted liquid-phase microextraction for determination of β2-receptor agonist drugs in wastewater.

Electromembrane extraction followed by high-performance liquid chromatography coupled with ultraviolet detection was validated for the determination and quantification of salbutamol (SB) and terbutaline in aqueous samples. A 200-V electrical field was applied to extract the analytes from 2.5 mL sample solution with pH 3.0, through an organic phase which consisted of 80% 2-nitrophenyl octyl ether, 10% di-(2-ethylhexyl) phosphate and 10% tris-(2-ethylhexyl)phosphate as supported liquid membrane into an acidic acceptor solution with pH 1.0, located inside the lumen of a hollow fiber. To achieve the best extraction conditions, the organic membrane composition was optimized separately and other parameters, such as extraction time, applied voltage and pH in sample solution and acceptor phase were studied using experimental design. Under optimal conditions, extraction recoveries of 53 and 43% were obtained for SB and terbutaline, respectively, which corresponded to preconcentration factors of 89 for SB and 72 for terbutaline. The method offers acceptable linearity with correlation coefficient higher than 0.9947 and relative standard deviation less than 4.7%. Finally, it was applied for analysis of drugs in wastewater samples.