New Fluorescence Derivatization Reagent for the Determination of 7 Unsaturated Fatty Acids in Oil Samples by Pre-Column Derivatization HPLC-FLD

Abstract

4-((2-Methyl-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinoline-6-yl)amino)-Ethyl-4-Methyl Benzenesulfonate (MNDMB), was designed and synthesized, and it was first successfully applied to label unsaturated fatty acids and HPLC-FLD determination. MNDMB can quickly complete the derivatization reaction with unsaturated fatty acids within 40 min with K2CO3 as the catalyst. The derivatives exhibit high stability and strong fluorescence properties with excitation and emission wavelengths of 285 and 522 nm, respectively. The 7 unsaturated fatty acid derivatives were separated on an Agilent ZORBAX 300SB-C18 column with gradient elution, and good linear correlation coefficients were obtained for all unsaturated fatty acids with correlation coefficients of ≥ 0.9998. The method has low limits of detection (LODs) (4–21 nmol/L) and good precisions ( intraday relative standard deviations [RSDs] were 1.91–3.51%, and interday RSD were 3.33–5.41%). The method was used to analyze two edible oils and successfully detected some unsaturated fatty acids with recoveries ranging from 90.2 to 103.5%. The proposed method has several advantages including specific labeling, simple enrichment operation, and high sensitivity, demonstrating its great utility for monitoring trace unsaturated fatty acids in various complex matrices.