Investigation of Migration Regularity of 49 Pesticides in Tea Infusion by GC-MS/MS

The 49 pesticides in tea infusion were determined by GC-MS/MS, then values of migration rate of pesticides were calculated by formula. Relationships between migration rate and solubility of pesticides, and between migration rate of pesticides and distribution coefficient (LogKow) in n-octyl alcohol-water was studied. The results showed that the range of migration rate of pesticides after tea soaking:the first soup was within 82.4%, the second soup was within 16.1%, and the migration rate of pesticides in the first soup was relatively high. The total migration rate of pesticides in tea soup was positively correlated with solubility in water (Pearson correlation coefficient was 0.743, P<0.01), the difference was statistically significant; and the total migration rate of pesticides in tea soup was negatively correlated with distribution coefficient in n-octyl alcohol-water (Pearson correlation coefficient was -0.984, P<0.01); the difference was statistically significant. Therefore, the migration rate of pesticides in the first soup after tea soaking was relatively high, so it was suggested to drop the first soup when drinking tea to reduce the pesticide exposure caused by tea infusion. Pesticides with low solubility in water and high distribution coefficient were recommended for tea planting.