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A sensitive confirmatory method for aflatoxins in maize based on liquid chromatography/electrospray ionization tandem mass spectrometry
Author(s) -
Cavaliere Chiara,
Foglia Patrizia,
Guarino Chiara,
Nazzari Manuela,
Samperi Roberto,
Laganà Aldo
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2873
Subject(s) - chemistry , chromatography , ammonium formate , electrospray ionization , detection limit , mass spectrometry , aflatoxin , tandem mass spectrometry , selected reaction monitoring , calibration curve , electrospray , analytical chemistry (journal) , acetonitrile , liquid chromatography–mass spectrometry , triple quadrupole mass spectrometer , food science
A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) method for measurement of aflatoxins B1, B2, G1, and G2 in maize is described. Aflatoxins (AFs) were extracted from 1 g samples by using tri‐portions of acetonitrile/water (80:20, v/v) (10 + 7 + 7 mL), and 2/5 of the extract diluted to 500 mL by water was cleaned up with a 100 mg Carbograph‐4 cartridge. After the addition of the internal standard AFM1, the final extract was analyzed by LC/ESI‐MS/MS in positive ion mode using multiple reaction monitoring with a triple‐quadrupole instrument. A C 18 column thermostatted at 45°C with a mobile phase gradient of acetonitrile/water with 2 mmol/L ammonium formate was used. Although the matrix suppression effect was negligible, quantitation was achieved by an external calibration procedure using matrix‐matched standard solutions to improve accuracy. Sample recoveries at four spiking levels ranged from 81 to 101% (relative standard deviation (RSD) ≤12%), and the method quantification limit ranged from 0.1 to 0.6 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 (2 µg/kg for aflatoxin B1 and 4 µg/kg for total AFs in corn products). This work also includes an application to samples obtained from retail markets and from experimental trial fields. Of the 48 samples, 15 were found to be contaminated with AFs and, of these, 5 did not comply with European Union legislation (AFB1 ≤2 µg/kg). Copyright © 2007 John Wiley & Sons, Ltd.