Ionic liquid as hollow fibre membrane carrier for extraction of fluoroquinolone antibiotics in milk coupled with high-performance liquid chromatography quantification

Abstract

A new hollow fibre liquid phase microextraction technology with an ionic liquid as the carrier was developed to determine the fluoroquinolone antibiotics in milk. In this technology, a porous polypropylene hollow fibre was filled with aqueous ionic liquid and the extraction efficiency of different factors, such as the type of hollow fibre membrane carrier, the pH and ionic strength of the donor solution, the pH of the acceptor solution, the stirring rate and the extraction time, were investigated. The optimised extraction condition was: [OMim][BF4] impregnated in the pores of the hollow fibre; 0.1 mol L−1 of Na2HPO4 (pH 11.0) as the acceptor solution was injected into the lumen of the hollow fibre; 0.1 mol L−1 H3PO4 (pH 5.0) was used as the donor solution; 600 rpm was selected as the stirring rate; 120 min was the optimum extraction time. The proposed method provided very high factors with 130-fold, 156-fold and 116-fold enrichment of ofloxacin, ciprofloxacin and enrofloxacin, respectively.