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B10-P: DETERMINATION OF AFLATOXINS IN TEA AND SPICES IN SERBIAN MARKET BY LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY

G. Vuković, M. Tadić, M. Cindrić,  M. Sarić

Institute of Public Health of Belgrade, Bulevar despota Stefana 54A, 11000 Belgrade

 

A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method [1, 2] was used for determination of aflatoxins B1, B2, G1 and G2 in tea and spices [3-5]. Aflatoxins (AFs) were extracted from 10 g of sample with 100 mL of methanol/water (80:20, v/v) and 50 mL hexane in blender jar, for 2 minutes. Methanol/water extract was filtrated, and an aliquot of 10 mL was diluted with 40 mL PBS buffer and cleaned up by immunoaffinity column (AflaClean, LCTech). Aflatoxins were eluted with 2x1 mL of methanol, and the final extract was analyzed by LC/ESI-MS/MS in positive ion mode using multiple reactions monitoring with a triple-quadrupole instrument. A C18 column was used for separation, with a mobile phase consisted of methanol/10mM ammonium acetate (40/60, V/V). Since, the matrix suppression effect was not negligible, quantitation was achieved by an external calibration procedure using matrix-matched standard solutions to improve accuracy. Sample recoveries at three spiking levels ranged from 81 to 101% (relative standard deviation RSD ≤ 12%) and the method quantification limit ranged from 0.5 to 1.1 µg/kg. This method is sensitive, accurate and selective, and can thus be applied as a confirmatory procedure in establishing non-compliance with EU permitted maximum levels (5µg/kg for aflatoxin B1 and 10 µg/kg for total AFs in spices). This work also includes an application to samples obtained from retail markets and from border inspection. Of the 66 samples (11 spices and 55 tea), 22 (33.3%) were found to be contaminated with AFs (5 spices and 17 tea) and of these 1 spice (9.8 mg/kg AFB1) and 2 tea (11.0 and 9.9 mg/kg AFB1) did not comply with Com. Reg. (EC) No 1881/2006.

References

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