Abstract: In order to obtain quality control standard for the analysis of bifenthrin residues in tea, a methodology was explored for establishing tea natural matrix reference material containing bifenthrin. Tea plants were due to the spraying of 0.17 g/L bifenthrin solution at a dosage of 3.0 g/mu (1 mu = 666.67 m2). Daily monitoring detection was conducted after the application of bifenthrin in tea plants. After tea picking at appropriate moment, normal tea making, and milling and screening through 120 mesh, the content of bifenthrin residues in 320 tea samples with independent bags from 2 batches were determined. The homogeneity and stability of the samples were examined. The chemical constituents of the samples were certified through collaborative analysis program and uncertainty assessment. The developed standard was applied to CNAS national proficiency testing program participated by 98 laboratories.

Key words: tea, bifenthrin residues, natural matrix, reference material