design of a new magnetic solid phase microextraction system for simultaneous separation and preconcentration of tetracycline and chloramphenicol

In this paper, a new, simple, low-cost, and selective magnetic solid phase microextraction system for simultaneous separation and preconcentration of tetracycline and chloramphenicol before their spectrophotometric determination has been designed based on as previous experiences [1-3]. in this method two molecularly imprinted polymer (mip) for specific sorption of tetracycline and chloramphenicol is synthesized on the surface of magnetic fe3o4 nanoparticles. each sorbent is held separately by a magnet in different part of a loop. then, the sample solution is passed through the loop causing selective extraction and preconcentration of each analyte on the respective sorbent. finally, the two sections of the loop are separated and each analyte is eluted by a proper sorbent and quantified. the major parameters affecting the extraction, including the sample ph, sample flow rate, sorbent amount, sample volume, eluent concentration, and eluent volume were investigated. the optimum conditions were: ph 6.0; flow rate, 5 ml min−1; amount of magnetic nanoparticles, 15 mg; sample volume, 50 ml, and eluent volume, 500 μl. under optimized conditions, a preconcentration factor of 100 and detection limits of 0.027 and 0.058 µg l-1 were achieved for tetracycline and chloramphenicol, respectively. the method was successfully applied to the determination of the analytes in natural water and serum samples.