Electromembrane Extraction of Organic Acid Compounds in Biological Samples Followed by High-Performance Liquid Chromatography.

Electromembrane extraction (EME) coupled with high-performance liquid chromatography was developed for determination of organic compounds including citric, tartaric and oxalic acid in biological samples. Organic compounds moved from aqueous samples, through a thin layer of 1-octanol immobilized in the pores of a porous hand-made polypropylene tube, and into a basic aqueous acceptor solution present inside the lumen of the tube. This new set-up for EME has a future potential such as simple, cheap and fast sample preparation technique for extraction of organic compounds in various complicated matrices. The pH of acceptor phase, extraction time, voltage, ionic strength, temperature and stirring speed were studied and optimized. Optimum conditions were: the pH of acceptor phase, 7; extraction time, 30 min; voltage, 30 V and stirring speed, 500 rpm. At the optimum conditions, the preconcentration factors of 175-200, the limits of detection of 1.9-3.1 µg L(-1) were obtained for the analytes. The developed procedure was then applied to the extraction and determination of organic acid compounds from biological samples.