Quantification of aflatoxin

Standards of B1, B2, G1, and G2 each of 3 ng/µL concentration were purchased from Sigma-Aldrich (California, USA). Various concentrations of aflatoxin (3, 30, 60 and 90 ng/µL) were prepared and were used to generate the standard curves, which allowed for external quantification of each targeted aflatoxin.

An internal standard griseofulvin was used to calculate the response factor. The internal standard calibration curve was developed by preparing various concentrations: 20, 40, 60, 80 and 100 ng/µL, each concentration analyzed in triplicates.

Peak areas of the excitation curves were used for quantification. Using the calibration curves the area obtained was converted to the concentration of aflatoxin contamination in ng/g. The results were compared with the standard recommended levels of aflatoxin in maize for human and livestock consumption.