| An efficient analytical method has been developed for the extraction and quantification of aflatoxin M1 in milk samples using
a modified air-assisted liquid-liquid microextraction method combined with high-performance liquid chromatography-fluorescence
detector. Firstly, defatted milk is transferred into a glass test tube
and its proteins are participated with zinc acetate solution. After
vortexing and centrifugation of the mixture, the obtained supernatant is removed and transferred into a conical bottom glass test
tube. Then, the adsorbed analyte onto the precipitated proteins is
eluted with acetonitrile and after centrifugation, the eluant is mixed
with the supernatant obtained from the previous step. A few microlitres of toluene (as an extraction solvent) is added into the solution
and the mixture is sucked into a glass syringe and pushed out in the
tube for four times. The obtained cloudy solution is centrifuged to
collect the extraction solvent. Then, the lower aqueous phase is
withdrawn by a glass syringe to transfer the extraction solvent to
the conical section of the tube. The method was validated and
under optimal conditions, it was found that the method has low
limits of detection (0.9 ng L−1) and quantification (3 ng L–1), good
linearity (r2 = 0.9976), and satisfactory repeatability (relative standard deviation ≤9% for intra- (n = 8) and inter-day (n = 6) precisions). The extraction recovery and enrichment factor of AFM1 were
87% and 87, respectively. Finally, the proposed method was applied
on different milk samples and concentration of aflatoxin M1 was
determined in the studied samples. |