Transfer Rates of 19 Typical Pesticides and the Relationship with Their Physicochemical Property

Determining the transfer rate of pesticides during tea brewing is important to identify the potential exposure risks from pesticide residues in tea. In this study, the transfer rates of 19 typical pesticides from tea to brewing were investigated using gas chromatography tandem mass and ultraperformance liquid chromatography tandem mass. The leaching rates of five pesticides (isocarbophos, triazophos, fenvalerate, buprofezin, and pyridaben) during tea brewing were first reported. The pesticides exhibited different transfer rates; however, this result was not related to residual concentrations and tea types. Pesticides with low octanol–water partition coefficients (Logkow) and high water solubility demonstrated high transfer rates. The transfer rates of pesticides with water solubility > 29 mg L^–1 (or <15 mg L^–1) were >25% (or <10%), and those of pesticides with LogKow < 1.52 (or >2.48) were >65% (or <35%). This result indicates that water solubility at approximately 20 mg L^–1 and LogKow at approximately 2.0 could be the demarcation lines of transfer rate. The results of this study can be used as a guide in the application of pesticides to tea trees and establishment of maximum residue limits of pesticides in tea to reduce pesticide exposure in humans

Transfer Rates of 19 Typical Pesticides and the Relationship with Their Physicochemical Property

Determining the transfer rate of pesticides during tea brewing is important to identify the potential exposure risks from pesticide residues in tea. In this study, the transfer rates of 19 typical pesticides from tea to brewing were investigated using gas chromatography tandem mass and ultraperformance liquid chromatography tandem mass. The leaching rates of five pesticides (isocarbophos, triazophos, fenvalerate, buprofezin, and pyridaben) during tea brewing were first reported. The pesticides exhibited different transfer rates; however, this result was not related to residual concentrations and tea types. Pesticides with low octanol–water partition coefficients (Logkow) and high water solubility demonstrated high transfer rates. The transfer rates of pesticides with water solubility > 29 mg L^–1 (or <15 mg L^–1) were >25% (or <10%), and those of pesticides with LogKow < 1.52 (or >2.48) were >65% (or <35%). This result indicates that water solubility at approximately 20 mg L^–1 and LogKow at approximately 2.0 could be the demarcation lines of transfer rate. The results of this study can be used as a guide in the application of pesticides to tea trees and establishment of maximum residue limits of pesticides in tea to reduce pesticide exposure in humans

Multiresidue Method for the Rapid Determination of Pesticide Residues in Tea Using Ultra Performance Liquid Chromatography Orbitrap High Resolution Mass Spectrometry and In-Syringe Dispersive Solid Phase Extraction

A method based on in-syringe dispersive solid phase extraction (IS-D-SPE) and ultra performance liquid chromatography Orbitrap high resolution mass spectrometry for the multiresidue analysis of 117 pesticides in tea was developed. Full scan mode was acquired over an <i>m</i>/<i>z</i> range of 100–800 with Orbitrap resolution at 70000, followed by full scan/dd-MS² mode for confirmation. The identification criteria of retention time and mass accuracy tolerance was ±0.20 min and ±5.0 ppm, respectively. MS/MS fragment ions obtained dd-MS² were necessary to identify the pesticides with the same molecular mass weight. The IS-D-SPE technique involved a mixture of 200 mg PSA, 100 mg C18, and 15 mg multiwalled carbon nanotubes for the cleanup of tea matrix. Good linearity (<i>R</i>² > 0.99) for 117 pesticides was obtained. Satisfactory recoveries in the range of 70–120% were obtained for 105 pesticides, while intraday and interday precisions were below 20%. Limits of quantification were generally 10 μg kg^–1. Finally, this method was employed to analyze 117 pesticides in 70 tea samples

Occurrence and risk assessment of organophosphorus pesticide residues in Chinese tea

<p>Tea is the second widely consumed beverage next to water. Tea drinking is one of the important pathways for human exposure of organonphosphorus pesticide. Consequently, incidence of organonphosphorus pesticide residues and risk assessment should be clear. In this study, the level of organonphosphorus pesticide residues in 810 Chinese teas manufactured between 2010–2013 was investigated using gas chromatography coupled with tandem mass spectrometry and a flame photometric detector. Incidence of organonphosphorus pesticide residues occurred with a frequency of 29% and the average concentration of 93 μg kg⁻¹. The residue levels varied from tea types, sale spots, and production area. Chlorpyrifos, isocarbophos, and triazophos were the only three organonphosphorus pesticides with detectable residues, and the detectable rates were 13.0%, 13.6%, and 17.4%, respectively. The corresponding average daily intake of chlorpyrifos, isocarbophos, and triazophos by tea drinking was 0.000083 μg kg⁻¹ bw day⁻¹, 0.0036 μg kg⁻¹ bw day⁻¹, and 0.0022 μg kg⁻¹ bw day⁻¹. These results showed that the total hazard quotient of organonphosphorus pesticide pesticides from tea drinking was less than 0.02 and that the tea-drinking originated organonphosphorus pesticide exposure had a little adverse health effect for human being.</p