反相高效液相色谱荧光衍生法测定土壤中的脂肪酸及质谱定性

Determination of Free Fatty Acids in Soil Sample by High-Performance Liquid Chromatography with Fluorescence Detection and Mass Spectrometry Identification

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙醇(BCE)作为柱前衍生化试剂,在Eclipse XDB-C8色谱柱上,通过梯度洗脱对19种游离脂肪酸进行了分离和在线质谱定性.以乙腈为溶剂,1-乙基-3-(3-二甲氨基丙基)环己碳二亚胺(EDAC)作为缩合剂,4-二甲氨基吡啶为碱催化剂(DMAP),60℃下衍生反应40 min后获得稳定的荧光产物.激发和发射波长分别为eλx=333 nm,λem=390 nm.采用大气压化学电离源(APCI)正离子模式,实现了土壤中脂肪酸的定性及相应含量测定.脂肪酸的线性回归系数大于0.9993,检测限在11.79-33.04 fmol.

A simple and highly sensitive method based on the derivatization of fatty acids utilizing 1,2- benzo-3,4-dihydrocarbazole-9-ethanol （BCE） as the novel pre-column derivatization reagent followed by high-performance liquid chromatography with fluorescence detection and online mass spectrometric identification is developed. Derivatization is obtained by the reaction of fatty acids with BCE at 60℃ for 40min in the presence of EDAC and DMAP in acetonitrile solvent. Derivatives are sufficiently stable to be efficiently analyzed by high--performance chromatography without pre-treatment. On a reversed--phase XDB-C8 column, nineteen kinds of free fatty acids （C1-C19） derivatives are separated and are sepctrometric identified online in conjunction with a gradient elution. The precise determination of fatty acids from soil sample is achieved by post-column online mass spectrometric identification with atmospheric pressure chemical ionization （APIC） source under positive mode detection. Linear responses are observed with coefficients of〉0. 9992, detection limits （at signal-to-noise of 3 ： 1） are 11.79-33.04 fmol.