Residue pattern and risk assessment of validamycin A and spinosyn A in tea using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry

Validamycin A (VA) and spinosyn A (SA) have been utilized as antibiotic pesticides in tea plantations for the control of pests and diseases. Both pesticides pose significant risks to human health and have been listed as key controlled new pollutants in China. So far, there have been few reports for the risk assessment of antibiotic pesticides in tea. In this study, a hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) method was developed for the simultaneous detection of VA and SA residues in tea. Method validation demonstrated good accuracy and precision. During tea planting, SA and VA in tea shoots degraded fast, with the half-life of 0.36 to 0.43 days for SA and 0.72 to 0.92 days for VA. SA and VA in tea shoots degraded fast initially and then followed by a slower phase. Both SA and VA degraded rapidly during the withering and drying stages. Compared to green tea, the degradation rates of both pesticides were faster during black tea manufacturing. Transfer rates of VA and SA from tea into infusions had transfer rates of 76.7 % to 99.5 % and 1.5 % to 2.7 %, respectively. The chronic risk quotient (RQc) < 1 for both antibiotic pesticides indicated negligible consumer risk from tea.