Measurement of Aflatoxin M-1 in Milk by Ultra-High-Performance Liquid Chromatography/Tandem Mass Spectrometry

作者：Chen Wen Ling; Hsu Tzu Fang; Chen Chia Yang^*

来源：Journal of AOAC International, 2011, 94(3): 872-877.

A sensitive method was developed using ultra-high-performance liquid chromatography (UHPLC)/MS/MS with positive electrospray ionization for determining aflatoxin M-1 (AFM(1)) in milk and milk powder. A 50 mL quantity of low-fat liquid milk containing 100 ng/L AFM(1) was prepared using immunoaffinity columns with a mean recovery rate of 79% (n = 3). UHPLC columns (BEH C-18, BEH HILIC, and HSS T3) greatly reduced the chromatographic time and lowered the instrumental detection limits (IDLs) 16 to 58 times compared to an HPLC column (Betabasic C-18). The HSS T3 column was chosen because it provided a low IDL (0.11 pg) and the lowest ion suppression of signal intensity (63.4%) among the tested columns. Matrix-fortified calibration curves were used for quantification and showed good linearity (r > 0.997) at 0.05-500 ng/mL. The LOD was 0.18 ng/kg for milk and 2.08 ng/kg for milk powder, based on the signal intensity of the confirmatory product ion (m/z 259.1), which was less abundant than the quantitative product ion (m/z 273.1). Certified reference materials of milk powder at three levels (<0.05, 0.111 +/- 0.018, and 0.44 +/- 0.06 mu g/kg) were measured within a day and between days; the results were all close to the certified levels with low variations (RSDs < 15%), showing good precision and accuracy.

• 出版日期2011-6