Meth ods:10%dethylenegly col succinate(DEGS)column was chosen and extractions with ethyl acetate from samples were methylated with BF 3 -ether /methanol.

• 方法:选用10%25丁二酸二乙二醇酯(DEGS)色谱柱,样品经乙酸乙酯提取后,用三氟化硼-乙醚/甲醇甲酯化处理。