Liquid-phase HPLC profiles of four aflatoxin congeners during contact with shell-derived chitosan nanostructures in acidic aqueous medium

This exploratory study examined the liquid-phase profiles of aflatoxins B1, B2, G1 and G2 during contact with chitosan prepared from Archachatina marginata shells. Physicochemically characterised chitosan was contacted with a mixed aflatoxin standard in 1% acetic acid at 25 °C for 72 h, and the filtered liquid phase was analysed by HPLC-DAD. The nominal starting concentrations were 0.376 μg mL −1 for AFB1 and AFG1 and 0.094 μg mL −1 for AFB2 and AFG2. Relative to the congener-specific analytical limits, AFB1 was above its limit of quantification, AFG1 and AFG2 were between their respective limits of detection and quantification, and AFB2 was below its limit of detection. After 24 h, AFB1 showed a markedly lower chromatographic response, while AFG1 remained detectable. AFB2 could not be assessed quantitatively, and interpretation of AFG2 was constrained by overlap with a signal in the unspiked chitosan blank. All four congeners were recorded as not detected after 48 and 72 h. These findings show changes in the detectable parent-aflatoxin profiles during contact under the tested conditions. Their interpretation is limited to the liquid phase because the experimental design did not distinguish adsorption from aflatoxin instability, transformation or handling losses. The study establishes an analytical basis for subsequent controlled adsorption, stability and mass-balance investigations of shell-derived chitosan.