[Evaluation of New Cleanup Agents for Analysis of Pesticide Residues in Tea].

We evaluated the effectiveness of new cleanup agents (S-NH and S-Si) compared with other previously reported cleanup agents (octadecylsilane, graphitized carbon, aminopropyl and silica gel) for removal of interfering substances such as catechin and caffeine prior to analysis of pesticide residues in tea. S-NH and S-Si were highly efficient in removal of catechin and caffeine, respectively. Recoveries of 80 pesticides using S-NH and S-Si were tested, and more than 70% of pesticides showed recovery greater than 70%. These results indicate that S-NH and S-Si agents will be useful for analysis of pesticide residues in tea.