Quantitative analysis of twelve sulfonamides in honey after acidic hydrolysis by high-performance liquid chromatography with post-column derivatization and fluorescence detection.

A quantitative HPLC-fluorescence method for the simultaneous determination of 12 sulfonamides (sulfaguanidine, sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamether, sulfamethazine, sulfamethoxypyridazine, sulfachloropyridazine and sulfadoxine) in honey was developed and validated. Sample pretreatment included acidic hydrolysis, followed by liquid-liquid extraction and solid-phase extraction on a strong cation exchanger. LC separation was performed in 45 min, with a total analysis time of 60 min. Identification and quantitation were based on retention time and fluorescence intensity, respectively. Peak area ratios of the target analytes and the internal standard were fit to a linear least-squares regression curve with a weighting factor of 1/x. Limits of detection and quantitation (LOQ) had values of 1 or 2 and 2 or 5 ng/g, respectively. Linearity was obtained with an average coefficient of determination (R2) higher than 0.997, over a dynamic range from the LOQ value up to 100ng/g. The method demonstrated good intra- and interbatch precision and accuracy. No interferences with the peaks of interest were observed throughout the chromatographic run. Sample pretreatment provided efficient cleanup, while post-column derivatization with fluorescamine proved to be a reproducible derivatization technique enabling a sensitive and rugged quantitative determination of sulfonamides.