A New Microchip Design. A Versatile Combination of Electromembrane Extraction and Liquid-Phase Microextraction in a Single Chip Device

For thefirst time, a novel and versatile microfluidic device wasdeveloped to achieve the possibility of combining different extraction principlesusing a miniaturized approach for the extraction of different classes of analytes.This novel microchip is composed of a sandwich of three poly(methylmethacrylate) (PMMA) layers. Four channels allowed the combination ofelectromembrane extraction (EME) and liquid-phase microextraction (LPME) inthree different ways: (I) EME and LPME, (II) EME and EME, or (III) LPME andLPME. The microchip can be used either (a) using a common acceptor phase (forboth extractions) for the simultaneous extraction of drugs from different nature in asingle step, or (b) a common sample solution (for both extractions) and twoacceptor solutions for simultaneous drug separation. In this work, the performanceof this novel microchip was demonstrated by simultaneous integration of EME andLPME using a common acceptor phase for both extractions. This configurationreduces the time of analysis allowing direct analysis in a single chip. The microchip was tested for extracting two different classesof analytes:fivefluoroquinolones and four parabens as model analytes. All effective variables were optimized for EME andLPME. Under the optimized conditions, the reusable microchip enables simultaneousμ-EME/LPME with extractionefficiencies over 77% in only 8 min extraction and sample volume consumption lower than 40μL. The optimized procedure wassuccessfully applied to urine samples obtaining recoveries over 90% for all analytes.