脂肪酸的提取

提取方法主要有Bligh—Dyer法及Folch法。前者适用于大量脂类的提取，提取率在

95％甚至更高；后者适用于少量组织内脂的提取，提取率在95％～99％。我们在实验中

常用Folch法。称取1 g待测样品，加入10 ml甲醇，加少量酸洗砂研磨，匀浆1 min，然后加入20 ml氯仿，继续匀浆2 min，过滤，滤渣中加入氯仿一甲醇混合液(2：1 V／V)30 ml 并研磨，过滤。先用20 ml氯仿及10 ml甲醇洗涤滤渣，合并滤液，然后加入全部滤液体

积1／4的水，振荡，静置分层，将上层及界面处固体物吸除去，然后加入甲醇一水混合物(1：1)，体积为下层体积的1／4，振荡，静置分层，吸掉上层液体及界面物，重复洗涤两次。然后将有机相减压蒸干，配制成氯仿溶液，一20℃下保存。注意：在分析植物组织中的脂质时，需要用加热法使植物中的脂酶失活。

1．皂化、酯化

取约4 mg的总脂按Carreau—Dubacq法，加入约1 ml 1．5％的NaOH／MeOH(或

1％Na／MeOH)溶液，在55。C水浴中加热30 min，然后加入1．5 ml HCl／MeOH，水浴加

热30 min，加0．5 ml左右的蒸馏水，然后用4 ml／Eg烷萃取，吸取正己烷层，重复两次。然后将萃取液减压蒸干，加入0．3 ml氯仿。

Modified Folch procedure

Homogenised tissue (10 g) was progressively added to

small amounts of a chloroform/methanol 2:1 (v/v) mixture

(up to 200 ml), with vigorous shaking, and then the

extraction was carried on for a further 2h, using an

electromagnetic stirrer. The mixture was filtered and the

filter was re-washed with fresh solvent and pressed.

Fifty millilitres of 0.88% potassium chloride were added

and the mixture was shaken. The aqueous layer (upper)

was removed by aspiration and the washing procedure

was repeated. The extract was then dried by adding

anhydrous sodium sulphate, which was filtered again,

before the solvent was removed using a rotary evaporator. The extract was then placed in a desiccator

overnight and weighed

Extraction by acid hydrolysis

Homogenised tissue (10 g) was progressively added to small amounts of a chloroform/methanol 2:1 (v/v) mixture (up to 200 ml), with vigorous shaking, and then the extraction was carried on for a further 2h, using an electromagnetic stirrer. The mixture was filtered and the filter was re-washed with fresh solvent and pressed.

Fifty millilitres of 0.88% potassium chloride were added and the mixture was shaken. The aqueous layer (upper) was removed by aspiration and the washing procedure was repeated. The extract was then dried by adding anhydrous sodium sulphate, which was filtered again, before the solvent was removed using a rotary evaporator. The extract was then placed in a desiccator

overnight and weighed

Extraction by ASE