Multi-residue analytical methods for pesticides in teas: a review

Tea is one of the most popular drinks worldwide. In the process of tea planting, for controlling pests, a variety of pesticides are usually applied. Therefore, pesticide residues and their metabolites in tea leaves, as well as their adverse effects on tea drinkers' health, are becoming increasingly concerning. The tea-leaf matrix is very complex because it is rich in organic acids, polyphenols, natural pigments, catechins, flavonols, metallic/non-metallic elements, and other unconfirmed substances. Hence, it is a great challenge to conduct multi-residue analysis of pesticides in tea samples. Researchers worldwide have been devoted to the development of multi-residue analytical methods for pesticide detection in tea and have made great progress in recent years. In this review, the recent advances in the multi-residue analysis of pesticides in tea matrices, especially those regarding matrix effects and their elimination, sample preparation and detection techniques, were reviewed in depth, and future research directions were suggested as well.