A high-performance method for quantitation of aflatoxins B1, B2, G1, G2: Full validation for raisin, peanut matrices, and survey of related products at Ho Chi Minh City.

Optimization and validation for simultaneous quantitation of four aflatoxins B1, B2, G1, and G2 in peanuts and raisins were performed on ultra-performance liquid chromatography in a combination of fluorescence detector, without derivatization. The advantages were short analysis time, simple sample handling, and reduced solvent consumption. Instrument detection limits of AFB1, AFB2, AFG1, and AFG2 were 0.07, 0.01, 0.1, and 0.008 μg/kg, respectively, lower than those obtained by LCMSMS and HPLC-FLD with derivatization. Two solvent mixtures were chosen for two different matrices whose matrix effect was not negligible (2.81%-8.04% for peanuts and 5.63%-11.43% for raisins). The linear ranges were from 0.2 to 20 μg/L for AFB1 and AFG1 and from 0.05 to 5 μg/L for AFB2 and AFG2. The limits of detection and quantification were 0.025-0.1 and 0.075-0.3 μg/kg for peanuts and raisins, respectively. Recoveries at three other concentrations from 0.75 to 125 μg/kg of total aflatoxins were obtained between 76.5% and 99.8% (with RSD < 6%) following the . Validation parameters complied with the requirements of ISO/IEC 17025:2017. The extracts and the sample could be stabilized at 4°C and 20°C for 24 h and at -20°C for up to 21 days, respectively. Thus, the study can be used as a standard method for the analysis of Aflatoxins (AFs) in peanut and raisin matrices. Investigation of 350 peanut samples collected at Markets in the central districts of HCM city showed that 28.6% were contaminated with AFB1 from 0.31 up to 554 μg/kg; 13.4% contained AFB2, and 5.7% of AFG1 in the range of 0.4-53 μg/kg and 0.4-9.57 μg/kg, respectively; AFG2 (about 0.6%) was detected from 0.45 to 0.75 μg/kg. Meanwhile, 12.8% exceeded the total aflatoxins limit, and 13.4% exceeded the AFB1 limit. AFs were almost not found in the 350 raisin samples.