Cárdenas M S, Ballesteros E, Gallego M, Valcárcel M
Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, Spain.
Anal Biochem. 1994 Nov 1;222(2):332-41. doi: 10.1006/abio.1994.1500.
A continuous system coupled to a gas-liquid chromatograph was used for the sequential determination of triglycerides and free fatty acids in serum and urine. The module provides compositional information and hence more detailed information on lipid metabolism changes in patients suffering metabolic disorders. Lipids in biological samples are manually extracted in methanol-n-hexane and introduced into the flow system; free fatty acids are then separated by retention on an ion-exchange resin and triglycerides (not retained) are transesterified with acetyl chloride in methanol. The resulting methyl esters are continuously injected into the gas chromatograph and determined by using a flame ionization detector. In a second step, retained free fatty acids are eluted and derivatized (also with acetyl chloride in methanol) and subsequently determined similarly as the triglycerides. The proposed method was applied to the determination of triglycerides in a lipid control serum; free fatty acids were determined in a human pool serum by the proposed method and compared with the volumetric method used in clinical practice. The results obtained in both instances showed good agreement between the results provided for triglycerides and free fatty acids. The proposed method was also applied to urine samples; a parallel recovery study was also made in order to assess the performance of the method.
一个与气-液色谱仪相连的连续系统用于血清和尿液中甘油三酯和游离脂肪酸的连续测定。该模块提供成分信息，从而能更详细地了解患有代谢紊乱的患者脂质代谢变化情况。生物样品中的脂质用甲醇-正己烷手动提取后引入流动系统；游离脂肪酸通过保留在离子交换树脂上进行分离，未保留的甘油三酯在甲醇中与乙酰氯进行酯交换反应。生成的甲酯连续注入气相色谱仪，并用火焰离子化检测器进行测定。第二步，将保留的游离脂肪酸洗脱并衍生化（同样在甲醇中用乙酰氯），随后与甘油三酯的测定方法类似进行测定。所提出的方法应用于脂质对照血清中甘油三酯的测定；用所提出的方法测定人混合血清中的游离脂肪酸，并与临床实践中使用的容量法进行比较。在这两种情况下获得的结果表明，甘油三酯和游离脂肪酸的测定结果之间具有良好的一致性。所提出的方法也应用于尿液样品；还进行了平行回收率研究以评估该方法的性能。
