应用6-O-异丙酰乙二胺荧光素(IPEF)作为柱前衍生试剂,结合高效液相色谱(HPLC)荧光检测,成功地衍生、分离并检测了食用油中12种脂肪酸:戊酸(C5)、己酸(C6)、庚酸(C7)、辛酸(C8)、壬酸(C9)、癸酸(C10)、月桂酸(C12)、肉豆蔻酸(C14)、棕榈酸(C16)、油酸(C18∶1)、硬脂酸(C18)、亚油酸(C18∶2)的含量.以1-乙基-3-(3-二甲胺丙基)碳酰亚胺(EDC)为缩合试剂,IPEF与羧酸在50℃反应40min即可较完全衍生.采用C18柱分离脂肪酸,色谱柱采用pH 6.5的甲醇-水(65/35,V/V)流动相平衡,进样后,流动相流速为0.8mL.min-1,检测波长λex为504nm,λem为525nm.该方法检出限可达0.2~0.8nmol.L-1.
A simple and highly sensitive method for the determination of 12 fatty acids n-valeric acid(C5),n-hexanoic acid(C6),n-heptanoic acid(C7),n-octanoic acid(C8),n-nonanoic acid(C9),n-decanoic acid(C10),lauric acid(C12),myristic acid(C14),palmitic acid(C16),stearic acid(C18),oleic acid(C18∶1) and linoleic acid(C18∶2) is described.The method is based on the separation of the 6-Oxy-(isopropionyl ethylenediamine) fluorescein(IPEF) derivatives of 12 fatty acids by high performance liquid chromatography with fluorescence detection.The derivatization reaction with 12 fatty acids was completed at 50 ℃ for 40 min using 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide(EDC) as the condensing reagent successfully.The chromatographic separation is performed using a mobile phase consisting of methanol-water(65/35,V/V) adjusted to pH 6.5 with Na2HPO4-H3Cit3 buffer on a Kromasil 100 C18 analytical column with flow rate of 0.8 mL/min and fluorescence detection at λex/λem=504 nm/525 nm.The detection limits were in the range of 0.2-0.8 nmol·L-1.