Liquid-phase microextraction using the microfluidic chip for the extraction of mesalazine from water and biological samples

Abstract

For the first time, a microfluidic device-based liquid phase microextraction followed by HPLC-UV analysis was introduced and optimized by response surface methodology (RSM) for the extraction and determination of mesalazine. Two symmetrical micro-channels separated by a support liquid membrane formed the microfluidic chip for passive diffusion of the target from the donor phase to the acceptor phase. The effects of the main variables, including the flow rate, pH of donor and acceptor phases, and solvent type, as well as their interactions were investigated on the extraction efficiency of the mesalazine and optimized by the D-optimal experimental design. The predicted extraction efficiency percentage of mesalazine at the optimal conditions (flow rate, 0.0197 mL/min; donor phase pH, 5.4; acceptor phase pH, 11.9; and solvent, 1-Butanol) was 100% and confirmed by its experimental value with an error of 0.1%. In addition, the procedure provided an acceptable repeatability with relative standard deviations lower than 2%, a detection limit of 0.81 ng/mL, and a quantitation limit of 2.7 ng/mL. This microfluidic chip was successfully applied for the determination of mesalazine in human plasma and urine samples with extraction efficiencies within the range of 88–92%. The proposed method provides advantages such as reduced sample consumption and extraction time, low cost, portability, and high extraction efficiency compared to the existing sample preparation techniques for mesalazine.