A reliable and rapid method has been developed for the determination of aflatoxin M1 (AFM1) in raw milk at the maximum allowable FDA limit of 0.5 ng/mL. Samples were artificially spiked (0.5 ng/mL AFM1) and extracted using Agilent QuEChERS extraction salts (6 g MgSO4, 1.5 g NaOAc). Clean-up was performed using PTFE (polytetrafluoroethylene) syringe filters. Extraction provided recoveries in the range of 62%-82% with relative standard deviations (RSDs) lower than 15%. For quantitative estimation of AFM1, measurements were performed on a HPLC system coupled to an Agilent 6460 Triple Quadrupole MS (HPLC-MS). The linearity of the method was evaluated with six matrix-matched standard solutions which were analyzed in duplicates ranging from 0.07�2.5 ng/mL of AFM1. The calibration curve was considered satisfactory with a correlation coefficient of 0.99. Sensitivity of the method was tested by examining the LOD and LOQ. The LOD and LOQ in spiked samples were 0.07 ng/mL and 0.25 ng/mL, respectively. Accuracy and precision were determined with intra-day and inter-day analysis at 0.25, 0.5, and 1.0 ng/mL AFM1 concentrations. There was no significant difference between the experiments performed on the same day or between day 1 and day 2 (inter-day analysis) at any concentration (p>0.5). Recoveries ranged from 46%-87%. RSDs were lower than 25% in all the cases. Selectivity was measured with AFM1 and AFG1 (0.5 ng/mL). Both aflatoxins exhibited good chromatography with acceptable baseline separation. The robustness of the method was also examined with slight modification in temperature (35�-45�), flow rate (0.5-0.7 mL/min), and gradient changes. Variation in the experimental parameters provided an indication of its reliability during normal use. This validation method describes a specific, sensitive, and reproducible assay using QuEChERS as an extraction method for the quantification of the FDA maximum allowable limit of 0.5 ppb AFM1 in raw milk.

Validation of aflatoxin M<sub>1</sub> in raw milk using QuEChERS as an extraction method

248th National Meeting (2014)

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Validation of aflatoxin M1 in raw milk using QuEChERS as an extraction method

Validation of aflatoxin M₁ in raw milk using QuEChERS as an extraction method