A comparative study of phenyl bonded-phase, CB and romer clean-up procedures for determining aflatoxin levels in maize by bi-directional HPTLC
A modified phenyl non-polar bonded-phase clean-up procedure for determining aflatoxin concentrations in aqueous acetone extracts of maize by bi-directional HPTLC was assessed. The accuracy and precision of the method was evaluated for a range of aflatoxin concentrations between 3.4 and 901 μg/kg. The coefficients of variation varied between 1.7 and 10.8% with mean recoveries of 92–99%. Application of regression analysis revealed systematic errors for aflatoxins B2 (−0.36 to −1.19%) and G2 (−0.03 to −0.57), and small relative errors for all four toxins. The limits of detection were 1.7 μg/kg (B1), 1.2 μg/kg (B2), 0.9 μg/kg (G1) and 0.8 μg/kg (G2).
The method was compared with the first action AOAC CB and Romer methods and a previously described PH bonded-phase procedure. It was found to recover significantly more aflatoxin from a sample of naturally contaminated maize, and to have accuracy better than and precision equivalent to the other methods. In addition, it was shown to be more rapid and cost effective than the AOAC methods.
Key WordsThin layer chromatography Bi-directional development Aflatoxin in maize Solid phase extraction AOAC methods
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