Transfer Behavior of Carbendazim from Dried Yingshan Yunwu Tea Leaves into Tea Infusions

Tea infusion is the main route of human exposure to pollutants in tea,and it is vital to investigate the transfer rate of pollutants from tea leaves to infusion.Carbendazim is a commonly used systemic fungicide,the transfer behavior of which in Yingshan Yunwu tea is not clear.Hence,this study firstly established the analytical method for determination of carbendazim with great accuracy and precision via modified QuEChERS method and ultra-performance liquid chromatography-fluorescence detection(UPLC-FLD).Then,the transfer behavior of carbendazim from tea leaves and infusion was systematically investigated.Results indicated that water temperature and proportion of tea to water ration would obviously increase the transfer rate of carbendazim,but times of infusion repetition showed negative correlation with the transfer rate of carbendazim.In addition,brewing time seemed to have lesser impact on the transfer rate.This study will be helpful for the risk assessment of carbendazim residue and provide the guidance for tea brewing.

Effects of Househould Cleaning Methods on Carbendazim Residue in Apples

Carbendazim,belonging to fungicides,was commonly used for controlling crop diseases,resulting in frequent residues in fruits and vegetables.Washing was the initial step of household fruit processing for cleaning and reducing pollutant contents.However,the effect of washing on the removal of carbendazim in apples was not systemically studied.Thus,in this study,an analytical method was firstly established for the determination of carbendazim with great accuracy and precision through quick,simple,cheap,effective and safe(QuEChERS)method and ultra-performance liquid chromatography-fluorescence detection(UPLC-FLD).Then,the influencing factors were systematically researched to unveil their effects on the carbendazim residue in apples.The results indicated that water temperature,washing products and washing method could obviously affect the carbendazim content in apples.In addition,the best cleaning scheme for removal of carbendazim was soaking apples for 5 min in a cleaning solution,which was prepared by dissolving 8 g of commercial fruit washing soup with 500 ml of water at 45℃.Under this condition,the removal rate of carbendazim in the washing step reached 73.91%.This study will be helpful for providing guidance for household cleaning methods for controlling pesticide residues.

锂硫电池中多硫化锂捕获研究进展

锂硫电池具有超高的理论比容量(1675 mAh/g)和理论比能量(2600 Wh/kg),并且单质硫在地球中的储量丰富、价格低廉、提取过程对环境友好,因此,锂硫电池被认为是未来储能系统的理想储能单元。然而,锂硫电池在充放电过程产生的多硫化锂中间体易溶于电解液,导致电解液的黏度增加,离子导电性降低。此外,溶解的多硫化锂通过在正负极之间迁移,与锂负极发生反应,产生严重的穿梭效应,造成活性物质硫的不可逆损失,极大地降低了电池的寿命和安全性,也阻碍了锂硫电池的商业化进程。近年来人们通过物理吸附、化学作用及外场约束等策略来攻关这一难题,并取得较好的结果。本文总结了物理、化学、外场三种捕获多硫化锂方法的研究进展,讨论了每种方法捕获多硫化锂的特点及其对锂硫电池电化学性能的影响,并对其未来发展进行了展望。