Verification and application of a HPLC-FLD method with immunoaffinity column cleanup for the analysis of citrinin in rice

This preliminary study aimed to verify an analytical method for the detection and quantification of citrinin (CIT) in commercial rice samples using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Ten rice samples of various origins were extracted, purified by immunoaffinity column (IAC), and analyzed by HPLC-FLD. The method showed excellent linearity (r2 = 0.999), with a LOD of 0.031 µg/mL and a LOQ of 0.103 µg/mL. Satisfactory precision was achieved (CV: 1.59–8.65%). Standard solution recovery was approximately 97%. Chromatographic peaks corresponding to CIT, identified by retention-time matching with the analytical standard following IAC cleanup, were observed in all samples. Putative CIT concentrations ranged from 126 to 229 µg/kg, mean 192 ± 35 µg/kg. To our knowledge, this is the first report of potential CIT contamination in rice from Türkiye. However, given the limited sample size, non-representative sampling design, and identification based on HPLC-FLD retention-time matching without LC-MS/MS confirmation, these findings are preliminary and should not be generalized beyond the rice samples analyzed in this study. Although CIT is a globally recognized mycotoxin, no specific limits exist for conventional rice. These findings support the need for larger monitoring studies, confirmatory LC-MS/MS analysis, and regulatory consideration for CIT in rice.