Analysis of aflatoxins in foods retailed in Saudi Arabia using immunoaffinity column cleanup and high-performance liquid chromatography-fluorescence detection

Abstract

A liquid–liquid extraction based high performance liquid chromatography-fluorescence method has been proposed for the quantitation of naturally producing aflatoxins in nuts and nut based products. Aflatoxins extraction from nuts and nut products was involved methanol – water extraction, immunoaffinity column cleanup followed by post column derivatization technique. The gel contents of monoclonal antibody of the column are very specific to the toxins of interest, which makes the extraction experiment rapid, simple, highly specific and sensitive. Additionally, the improve concentration of toxins from complex nuts and nut product matrices helps to reduced chromatography interference and lower limit of detection. The proposed method was authenticated to evaluate the performance in terms of linearity of the calibration, limit of detection, recovery, run-to-run (repeatability) and day-to-day precision (reproducibility). Good quality parameters with LOD between 0.003 and 0.007 ppb, recovery from 89 to 98%, linearity in the range of 0.02 to 100 ppb (r2 > 0.989) and precisions with RSDs were achieved below 4.5% at concentration level of 1.0 and 30.0 ppb. The developed method was effectively used to the analysis of aflatoxins (AFB1, AFB2, AFG1, and AFG2) in twenty nuts and nut products and were found up to 120.1 ng/mL AFB1 and 11.2 ppb AFB2 in few of the samples. Keywords: Liquid chromatography, Fluorescence detector, Aflatoxins, Nuts and nut products