Online Enrichment Combined with High Performance Liquid Chromatography for Quantitation of Trace-level Chloramphenicol in Milk

With growing concerns over food safety, more accurate, simpler, and faster detection methods are urgently required. An online enrichment system with a molecularly imprinted polymer (MIP) for chloramphenicol (CAP) was coupled to HPLC using a flow-injection pump and developed and validated for the analysis of trace levels of CAP in milk. Compared with direct injection into the HPLC, the developed analytical method had a lower limit of detection (0.01 mu g L-1) and an enrichment factor of 364 because of the specific adsorption of CAP on the MIP. The linear range of the method was 0.05 mu g to 10 mg (r(2) > 0.99). After online purification and enrichment, the trace amounts of CAP in milk could be quantified, with limit of detection in milk of 0.1 mu g kg(-1) and recoveries ranging from 82.6 % to 98.1 % at different spiked levels of CAP in raw milk, and commercial liquid milk.