A single-laboratory ultra-performance liquid chromatography-mass spectrometry method was developed and validated for the estimation of tetraniliprole, BCS CQ 63359, spirotetramat and its metabolites from chilli and brinjal (commonly known as eggplant, aubergine or guinea squash) samples for assessing the dissipation kinetics and dietary risk assessment of field-applied tetraniliprole and spirotetramat. The control samples of brinjal and chilli fortified with tetraniliprole, spirotetramat and their metabolites at three levels of 0.01, 0.05 and 0.1 mg kg−1, when extracted with acetonitrile followed by PSA clean up, showed a recovery values in the range of 71-111% with relative standard deviation, RSD ≤ 7.5%. Combination product (tetraniliprole 120 g L−1 + spirotetramat 240 g L−1 SC) was applied three times at 7-day intervals in brinjal and chilli, from fruit setting stage, at 375 and 469 ml ha−1 dosages. The half-lives of Σ tetraniliprole at lower and higher doses were 1.20 and 1.44 days, while those for Σ spirotetramat were 1.13 and 1.32 days in brinjal. Similarly, the half-lives of Σ tetraniliprole at lower and higher doses were 3.37 and 4.79 days, while those for Σ spirotetramat were 1.81 and 2.74 days, respectively in chilli. The risk evaluation of the residues revealed that the combination product applied at lower and higher doses in brinjal and chilli did not pose any risk to humans, even when consumed only two hours after the initial application, and hence can be safely recommended for controlling of pest complexes in brinjal and chilli under humid tropical conditions in India.
George et al. (Wed,) studied this question.