微藻脂肪酸组成测定方法概述

A Review of Methods for Determining Microalgal Fatty Acid Composition

微藻脂肪酸测定步骤一般是先将微藻样品进行前处理(脂类抽提、皂化、甲酯化以及脂肪酸甲酯的萃取),然后将得到的脂肪酸甲酯在气相色谱-质谱仪上分析并计算,得出脂肪酸的含量和组成。文中概述了测定微藻脂肪酸时,样品前处理过程中不同的皂化、甲酯化和萃取方法,以期为微藻科学研究和开发利用提供理论依据。样品前处理过程中皂化的方法主要有氢氧化钠甲醇法、氢氧化钾甲醇法等。甲酯化的方法主要有酸催化法(盐酸甲醇法、硫酸甲醇法、三氟化硼甲醇法和三氯化硼甲醇法等)、碱催化法(氢氧化钾甲醇法)以及其他一些甲酯化的方法(乙酰氯甲醇法、硅烷化试剂法以及重氮甲烷法等);其中乙酰氯甲醇法可直接对干燥的微藻样品进行甲酯化处理而得到脂肪酸甲酯,具有操作简便、用时短、效果好的优点。脂肪酸甲酯的萃取方法主要有正己烷萃取法、石油醚萃取法、戊烷萃取法以及其他一些萃取方法(乙醚、环己烷、乙酸乙酯等)。上述各种处理方法各有优缺点及适用范围,在实际应用时,根据实际需要选择合适的测定方法。

Determining microalgal fatty acid composition includes pretreating（lipid extraction,saponification,methyl esterification and fatty acid methyl esters extraction） and quantifying fatty acid methyl esters with gas chromatography and deducing fatty acids and their content.In this review,diverse methods of saponification,methyl esterification and fatty acid methyl esters extraction at sample pretreatment step are compared in order to facilitate theoretical and practical researches of microalgae.Sodium hydroxide methanol and potassium hydroxide methanol methods and among others are available for saponification.Acid catalytic actions with hydrochloric acid methanol,sulfuric acid methanol,boron trifluoride methanol and boron trichloride methanol,base catalytic action with potassium hydroxide and other catalytic actions with acetyl chloride methanol,silane reagent and diazomethane are available for methyl esterification.Of these methods,acetyl chloride methanol is highly performing;it is convenient for use,time saving and highly effective.With this method,fatty acids in dry microalgal powder can be methyl esterified.Hexane,petroleum ether and pentane extractions and among other extractions with ether,cyclohexane,ethyl acetate and so on are available for fatty acid methyl esters extraction.The methods mentioned above each holds advantages and limitations at the same time,which should be evaluated ahead of use.