有色蔬菜农药多残留检测样品预处理方法研究

Sample Preparation Methods for Deep Color Vegetables in Multi-residue Analysis of Pesticides

以韭菜、油菜、菠菜和胡萝卜为试材,在样品均质前添加石墨粉并采用SPE固相萃取方法进行提取液净化处理,分析其脱色效果,并对样品中72种农药的回收率进行测定,探讨有色蔬菜农药多残留GC-MS检测中的样品预处理方法。颜色较浅样品提取液净化时,用300mg石墨柱与PSA柱串联,可以有效地排除样品提取液中色素的干扰,使94%以上农药的回收率介于60%～120%之间。颜色较深样品除进行上述处理外,在样品均质前添加少量石墨粉,不仅可以获得理想的脱色效果,而且待测农药的吸附损失也较少,90%以上农药的添加回收率在60%～120%范围内,可以达到理想的检测效果。

Sample preparation methods for deep color vegetables in multi-residue analysis of pesticides were studied by comparing discoloration effects of different clarifying method for crude extract and analyzing the recoveries of 72 kinds of pesticides in standard solution and vegetable samples. Results showed that combined use of mini-column fiUed with 300 g graphite and PSA mini-column for light color vegetables can get satisfactory results. With this treatment, the recovery for 94% among 72 kinds of pesticides ranged within 60%~ 120%. For deep color vegetable, however, it is necessary to add a little of graphite into samples prior to homogenization besides the above treatment, which can lead to complete eliminate the interference of pigment in the sample and lower absorbing losses. The recovery of more than 90% among 72 different kinds of pesticides existed in vegetable samples ranged within 60%~ 120%.