Determination of aflatoxin M₁ in milk by triple quadrupole liquid chromatography-tandem mass spectrometry

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.

Keywords:

• liquid chromatography/mass spectrometry (LC/MS)
• method validation
• aflatoxins
• animal products
• 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.