Electro membrane extraction of biological anions with ion chromatographic analysis

A simple and sensitive single step electro membrane extraction (EME) procedure was demonstrated for biological organic anions with determination by ion chromatography (IC). Nitrite, adipate, oxalate, iodide, fumarate, thiocyanate and perchlorate were extracted from aqueous donor solutions, across a supported liquid membrane (SLM) consisting of methanol impregnated in the walls of a porous polypropylene membrane bag and into an alkaline aqueous acceptor solution in the lumen of the propylene envelope by the application of potential of 12V applied across the SLM. The acceptor solution was analyzed by IC. Parameters affecting the extraction performance such as type of SLM, extraction time, pH of the donor and acceptor solution, and extraction voltage were studied. The most favorable EME conditions were methanol as the SLM, extraction time of 5min, pH of acceptor and sample solutions of 12 and 4, respectively, and a voltage of 12V. Portable 12V batteries were used in the study. Under these optimized conditions, all anions had enrichment factors ranging from 3.6 to 36.2 with relative standard deviations (n=3) of between 6.6 and 17.5%. Good linearity ranging from 0.1 to 10μgmL ^-1 with coefficients of correlation (r) of between 0.9981 and 0.9996 were obtained. The limits of detection of the EME-IC method were from 0.01 to 0.14μgmL ^-1. The developed methodology was applied to amniotic fluid samples to evaluate the feasibility of the method for real applications.