Optimization of Matrix Solid-Phase Dispersion Method for Extraction of Aflatoxins from Cornmeal

An extraction method for simultaneous determination of aflatoxins (AFLAs) G2, G1, B2, and B1 in cornmeal, based on vortex-assisted matrix solid-phase dispersion (MSPD) and high-performance liquid chromatography (HPLC) with fluorescence detection was optimized by a central composite design, validated and applied. Multivariate analysis was performed to evaluate the effect of cornmeal composition on AFLA extraction. The amount and proportion of solid support (celite and C18) and volume of elution solvent (methanol and acetonitrile) were the variables tested. The mobile phase of methanol/acetonitrile/water (24:14:62, v/v/v) in isocratic elution mode provided satisfactory AFLA separation. The best recoveries (85.7 to 114.8%) were obtained when the sample preparation contained 25mg C18 as solid support and 10mL of elution solvent. The limits of detection ranged from 0.01 to 0.04ngg(-1), and the limits of quantification varied from 0.02 to 0.1ngg(-1). The optimized method was suitable for coarse and medium grind cornmeal. Multivariate correlation analysis showed that the main interferers for AFLA recovery were proteins and sugars.