Determination of aflatoxin isomers in red chilli using uhplc method

A simple and sensitive ultra high-performance liquid chromatography with fluorescence detector based analytical method was developed for the separation and quantification of aflatoxin isomers residues in red chilli samples. The separation was performed on purospher STAR RP 18e column with an optimised solvent system consisting of 0.2% acetic acid in water and 1:1 methanol and acetonitrile. The response of detector was linear with correlation coefficient >0.99 and limit of quantification was 2 μg kg⁻¹. Calibration curves were linear in the concentration range of 2–50 ng mL⁻¹. A satisfactory RSDr and recoveries were in the range of 0.1–4.2% and 82.9–114.7%, respectively. The validated method was applied to quantify aflatoxin isomers residues in 48 red chilli and red chilli powder samples collected from the farmers’ field, cold storage and local market. The study revealed that, the AFG₁ and AFG₂ were not detected in the collected samples and the red chilli powder samples collected from local market showed the presence of AFB₂ in 2 samples which was below the quantification limit (<1 μg kg⁻¹). Whereas, the contamination of AFB₁ was detected in 5 and 19 samples out of 22 field collected red chillies and 23 local market collected red chilli powder, respectively. However, none of the cold storage collected samples shown the presence of AFB₁ This method could be used for monitoring of four different isomers of aflatoxin in different agricultural and horticultural produce.