Abstract: 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 filled 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%.

Key words: vegetable, pesticide, residue, pigment, sample preparation