植物类脂的提取及对菲吸附的影响

Extractions of lipids from plants and the effects on sorption of phenanthrene

讨论了有机溶剂极性对植物类脂提取的影响,分别采用(Ⅰ)非极性正己烷和(Ⅱ)极性三氯甲烷∶甲醇(2∶1)溶液从青椒和油麦菜干样中索氏提取植物类脂,进一步研究了上述植物干样、提取类脂和去类脂组分对菲的吸附.实验结果表明,两种方法提取得到的类脂含量不同,方法(Ⅰ)从青椒和油麦菜中提取得到类脂含量为(1.9±0.1)%和(5.0±0.4)%;而方法 (Ⅱ)提取得到的相应值分别为(2.6±0.2)%和(9.5±0.5)%.两种方法得到提取类脂对菲的吸附贡献无显著性差异(P>0.05),均约占整个青椒干样对菲吸附的20%,而油麦菜的这一比例约为60%.但采用正己烷提取可避免极性物质的析出而更好地分离类脂和去类脂组分.去类脂组分在青椒和油麦菜中对菲的吸附贡献分别约为80%和40%,即去类脂组分对菲仍有较强的吸附能力,因此不能简单视为碳水化合物.

This work studied the effects of the polarity of organic solvents on the extraction of lipids from plants.（Ⅰ） Hexane,a nonpolar organic solvent,and（Ⅱ） a mixed solvent of chloroform and methanol（2 ∶ 1）,were used to extract lipids by Soxhlet extractor from green pepper and leaf lettuce.The extracted lipids and the de-lipidized plant samples,along with the original dry plant samples,were used to sorb phenanthrene.The results showed that the two solvents had differential extraction abilities in that solvent（Ⅰ） extracted（1.9±0.1）% and（5.0±0.4）% lipids from green pepper and leaf lettuce,respectively,while solvent（Ⅱ） extracted（2.6±0.2）% and（9.5±0.5）% lipids,respectively.However,no significant difference（P0.05） was observed in the contributions of the determined lipid fractions to the overall phenanthrene sorption.These contributions were approximately 20% for green pepper and 60% for leaf lettuce,respectively.Using hexane as the extraction solvent could avoid the simultaneous extraction of polar constituents and thus more properly separate the lipids and de-lipidized plants.The de-lipidized plants may not be simply regarded as the carbohydrate fractions of the plants,because the contributions of de-lipidized plants to the overall phenanthrene sorption remained significant at approximately 80% for green pepper and 40% for leaf lettuce.