A novel approach to the consecutive extraction of drugs with different properties via on chip electromembrane extraction
In the present research, for the first time, a consecutive on chip electromembrane extraction coupled with high performance liquid chromatography was introduced for the analysis of betaxolol (Bet), naltrexone (Nalt) and nalmefene (Nalm) as model analytes with different chemical properties from biological samples. The chip consists of two polymethyl methacrylate (PMMA) parts where two microfluidic channels are carved in each part. These channels were used as a flow path for the sample solution and a thin compartment for the acceptor phase. A porous polypropylene sheet membrane impregnated with an organic solvent was placed between two parts of the chip device in order to separate the channels. Two platinum electrodes were bent at the bottom of these channels that are connected to a power supply providing the electrical driving force for migration of ionized analytes from the sample solution through the porous sheet membrane into the acceptor phase. The new setup provides effective and reproducible extractions by using a low volume of sample solution. Efficient parameters on consecutive electromembrane extraction of the model analytes were optimized by using the one variable at a time method. Under the optimized conditions, the new setup offered a good linearity in the range of 10.0–500 μg L−1 with coefficient of determination (R2) higher than 0.9932. The relative standard deviation (RSD%) and LOD values were less than 6.8% based on four replicate measurements and 10.0 μg L−1 for the model analytes, respectively. The preconcentration factors higher than 15.6-fold were obtained. Finally, the proposed method was successfully applied for determination and quantification of the model analytes in biological samples.