Determination of trans-fatty acids in food samples based on the precolumn fluorescence derivatization by high performance liquid chromatography

Trans-fatty acids (TFAs) are unsaturated fatty acids that are considered to have health risks. 1,3,5,7-Tetramethyl-8-butyrethylenediamine-difluoroboradiaza-s-indacene is a highly sensitive fluorescent labeling reagent for carboxylic acids developed by our lab. In this study, using this precolumn fluorescent derivatization reagent, a rapid and accurate HPLC-fluorescence (FL) detection method was developed for the determination of two TFAs in food samples. Under the optimized derivative conditions, two TFAs were tagged with the fluorescent labeling reagent in the presence of 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide at 25 degrees C for 30 min. Then, the baseline separation of trans- and cis-fatty acids and their saturated fatty acid with similar structures was achieved with less interference using a reversed-phased C-18 column with isocratic elution in 14 min. With FL detection at lambda(ex)/lambda(em )= 490 /510 nm, the linear range of the TFAs was 1.0-200 nM with low detection limits in the range of 0.1-0.2 nM (signal-to-noise ratio = 3). In addition, the proposed approach was successfully applied for the detection of TFAs in food samples, and the recoveries using this method ranged from 96.02 to 109.22% with low RSDs of 1.2-4.3% (n = 6).