Determination of aflatoxin M1 and B1 in milk and jujube by miniaturized solid-phase extraction coupled with ultra high performance liquid chromatography and quadrupole time-of-flight tandem mass spectrometry.

A miniaturized solid-phase method was proposed for the extraction of aflatoxin M1 and B1 from milk and jujube samples. Target analytes were identified by ultra high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry in positive mode. The main factors that affected the extraction ability and sensitivity of the analytical method were evaluated in detail. In the optimal conditions, 30 mg of silica particles functionalized with octadecyltrimethoxysilane and methanol were used as sorbent and desorption solvent in miniaturized solid-phase extraction, respectively. The calibration curves for aflatoxin B1 and M1 showed good linearity (r2  > 0.9921) within linear ranges. The limit of detection (S/N = 3) were determined to be 0.049 and 0.023 μg/kg for aflatoxin M1 and B1, respectively. In addition, the good spiked recoveries were obtained ranging from 88.24 to 105.35%. The results demonstrated that the proposed method had significant advantages including simple, inexpensive, rapid, and accurate, which considered as a suitable method for the trace analysis of aflatoxins.