Improved Method for the Extraction and Determination of Bromophenols in Seafoods by High-Performance Liquid Chromatography with Fluorescence Detection

A sensitive precolumn derivatization method using 10-methylacridone-2-sulfonyl chloride (MASC) as derivatizing reagent followed by high-performance liquid chromatography (HPLC) with fluorescence detection has been developed for the determination of naturally occurring bromophenols in seafoods. Instead of using a traditional complex steam distillation solvent extraction method, the extraction method was modified by using sulfuric acid hydrolysis followed by hexane extraction and subsequent alkaline back extraction to obtain good recoveries and fewer interferences. Batch analysis of bromophenols thus became more performable because the sample amount and analysis time were greatly reduced. The recoveries of the five bromophenols were >80% with a noticeable improvement for 4-BP, the recoveries of which were usually <40% when analyzed by traditional methods. The HPLC sensitivity for the determination of bromophenols was greatly enhanced through derivatization. Under optimal conditions, the quantification limits obtained by using 4.0 g of sample were in the range of 0.60-1.0 ng/g. This is the first time that derivatization was applied to enhance the HPLC sensitivity of bromophenols. The proposed method was successfully applied to the determination of the target compounds in seafoods with a much higher sensitivity than traditional HPLC method.