Abstract:

A poly (methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column was prepared and applied as an extraction device, the extraction performance of doxycycline and chlortetracycline was investigated. By combining the polymer monolith mcroextraction (PMME) and sweeping micellar electrokinetic chromatography with cation-selective exhaustive injection(CSEI),the method for the quantitative monitoring of doxycycline and chlortetracycline residues in chicken was established. To obtain the optimum extraction efficiency, several parameters relating to MEKC (such as pH, buffer concentration, SDS concentration, separation voltage), CSEI (sample solvent, injection voltage and time, water plug length）and PMME (including extraction volume, pH value of the sample matrix and sample solvent) were systematically investigated. Under the optimum conditions, low detection limits (3.4 ng/g for doxycycline and 12.6 ng/g for chlortetracycline) and quantification limits (11.39ng/g for doxycyline and 41.99ng/g for chlortetracycline) were obtained. The proposed method showed good linearity ranging from 50 to 1000 ng/g. The recoveries for fortified chicken samples were ranged from 85.1 to 91.7%. Excellent reproducibility of the method was exhibited by intra- and inter-day precisions with the relative standard deviations less than 8.2%. The proposed method was simple, sensitive, accurate and low cost, and it can be applied to simultaneously determine the doxycycline and chlortetracycline residues in chicken samples.