Qualitative Analysis of Active Beta-Lactamases in Milk Samples by Rapid Resolution Liquid Chromatography-Tandem Mass Spectrometry
A rapid resolution liquid chromatography-tandem mass spectrometric method (RRLC-MS/MS) has been developed for the qualitative analysis of active beta-lactamases in milk samples. Penicillin was added to the samples solution to enzymolyze the active beta-lactamases. Then,the analytes were extracted by CH3CN-H2O from homogenized samples,and the extract was cleaned by Oasis HLB solid phase extraction cartridge. Quantification of penicillin was achieved by RRLC-MS/MS with multiple reaction monitoring. Detection limit of active beta-lactamases was 4 U/mL,the mean recoveries were in the range of 92.3%-95.5%,and the RSD was less than 10%(n=6). The results of this method were consistent with these by the cylinder plate method.