Abstract
A sensitive and reliable method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an electrospray-positive ionization method was developed for the determination of aflatoxin M1 in milk. This method includes simple extraction of the sample with acetonitrile by ultrasonic, separation on an MGIII-C18 column using 0.01% formic acid buffer/acetonitrile (60 : 40, v/v) as mobile phase, and MS/MS detection using multiple reaction-monitoring mode. Average recoveries of aflatoxin M1 from spiked samples at concentrations of 0.02 and 1 ng ml−1 ranged from 77% to 94%, with a 6% relative standard deviation. The limit of detection and limit of quantification were 0.006 and 0.02 ng ml−1, respectively. The standard curve was linear between 0.02 and 20.0 ng ml−1. The recommended method is simple, rapid, specific and reliable for the routine monitoring of aflatoxin M1 in milk.
Acknowledgements
The authors are highly appreciative of Mrs Cao Hong for skilful and zealous technical assistance and of Mr Gen Jianqiang for help in obtaining the milk samples.