Comparison of liquid chromatography instruments with single quadrupole and tandem mass spectrometry for trace level analysis: Aflatoxin m1 (afm1) in white cheese

Abstract

ABSTRACTAlthough the mycological content of white cheese has been extensively studied, little data is available concerning the existence of aflatoxin M1 (AFM1) in Egyptian white cheese. Egyptian legislation does not allow for AFM1 in milk or milk products. In this study, trace amounts of AFM1 contamination were detected in laboratory manufactured Egyptian white cheese using either single or triple quadrupole techniques after artificial exposure of AFM1 to raw milk used for the cheese making. Validation data proved that the triple quadrupole method was more sensitive and selective than the single quadrupole method for AFM1 analysis. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.0625 ppb and 0.125 ppb for the triple quadrupole method and 0.125 ppb and 0.250 ppb for the single quadrupole method. Recovery of AFM1 ranged from 87% to 92% for single quadrupole and 89% to 99% for triple quadrupole using mass spectrometer techniques. Linear regression produced linear standard curves with coefficients of determination of regression of 0.9981 and 1.000 for the single and triple quadruples, respectively. Although both methods were able to measure AFM1, the tandem mass spectrometer produced results that were more reliable.