茶叶中653种农药化学品残留GC-MS、GC-MS/MS与LC-MS/MS分析方法：国际AOAC方法评价预研究

选择了16个实验室,按AOAC方法评价指南对盲样进行了检测。对16个实验室的统计分析结果表明:剔除操作偏离方法的2个实验室的全部数据,剩余14个实验室GC-MS/SIM(GC-MS/MS):RSDr<8%的占100%;RSDR<16%的占57.5%,RSDR<25%的占92.5%;HorRat值小于1.0的占80.0%,HorRat值小于2.0的占97.5%。LC-MS/MS:RSDr<8%的占65.0%,RSDr<15%的占97.5%;RSDR<16%的占35.0%,RSDR<25%的占95.0%;HorRat值小于1.0的占92.5%,HorRat值小于2.0的占97.5%。建立的1 220条标准曲线中,有1 132个满足r2≥0.995的要求,占92.8%;检测目标农药离子3 600个,离子丰度符合EU要求的有3 443个,占95.6%。AOAC方法评价结果证明,该方法重现性和再现性良好,完全适用于茶叶中653农药残留的定性和定量分析。     

玫瑰花茶的金属元素含量及其保健功能分析

采用V（HNO3）＋V（HClO4）=5＋1对玫瑰花茶进行消解,用火焰原子吸收光谱法测定了其中金属营养元素的含量。结果表明,玫瑰花茶中含有丰富的人体所必需的金属元素,其中钾、钙、钠、镁、铁、锰、铜、锌含量分别为11．6559,6．5642mg／g,23．3147μg/g,2．0533mg／g,25．8711,20．5897,7．9107,23．2493μg/g,各元素比例有利于人体吸收,具有较高的营养保健价值,为人们选用花茶提供了一定的理论依据。     

电感耦合等离子体质谱分析莲子芯茶中的稀土元素

建立了一种压力密闭消解电感耦合等离子体质谱法测定莲子芯茶中Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu等15种稀土元素的方法。用该方法分析国家标准物质中的稀土元素,分析结果与标准值一致,并用该方法对莲子芯茶实际样品进行了分析。     

Potential Use of Tea Tree Oil as a Disinfectant Agent against Coronaviruses: A Combined Experimental and Simulation Study

The COVID-19 pandemic has highlighted the relevance of proper disinfection procedures and renewed interest in developing novel disinfectant materials as a preventive strategy to limit SARS-CoV-2 contamination. Given its widely known antibacterial, antifungal, and antiviral properties, Melaleuca alternifolia essential oil, also named Tea tree oil (TTO), is recognized as a potential effective and safe natural disinfectant agent. In particular, the proposed antiviral activity of TTO involves the inhibition of viral entry and fusion, interfering with the structural dynamics of the membrane and with the protein envelope components. In this study, for the first time, we demonstrated the virucidal effects of TTO against the feline coronavirus (FCoVII) and the human coronavirus OC43 (HCoV-OC43), both used as surrogate models for SARS-CoV-2. Then, to atomistically uncover the possible effects exerted by TTO compounds on the outer surface of the SARS-CoV-2 virion, we performed Gaussian accelerated Molecular Dynamics simulations of a SARS-CoV-2 envelope portion, including a complete model of the Spike glycoprotein in the absence or presence of the three main TTO compounds (terpinen-4-ol, γ-terpinene, and 1,8-cineole). The obtained results allowed us to hypothesize the mechanism of action of TTO and its possible use as an anti-coronavirus disinfectant agent.     

利用高光谱图像技术评判茶叶的质量等级

针对茶叶品质无损检测时内外品质难以同时兼顾的问题,利用高光谱图像技术检测茶叶质量.设计一套基于光谱仪的高光谱图像系统采集数据;通过主成分分析,从海量数据中优选出三个波长段的特征图像;从每个特征图像中分别提取平均灰度级、标准方差、平滑度、三阶矩、一致性和熵等6个基于统计矩的纹理特征参量,每个样本共有18个特征变量;再通过主成分分析对这18个特征变量进行压缩,提取8个主成分因子建立基于反向传播神经网络的茶叶等级判别模型.模型训练时的总体回判识别率为97%;预测时总体识别率为94%.结果表明,高光谱图像技术可以用于茶叶质量等级水平的评判.     

近红外光谱法快速检测绿茶中儿茶素的含量

提出了一种应用傅里叶近红外漫反射光谱分析技术快速检测茶叶中主要儿茶素含量的新方法.首先获取茶叶在10000～4000 cm<'-1>范围的近红外漫反射光谱,然后以高效液相色谱分析值作参考值.采用偏最小二乘法建立茶叶中表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)和表没食子儿茶素(EGC)含量的定量分析模型.通过交互验证方法来优化模型的主成分数和所采用的光谱预处理方法.EGCG、ECG和EGC三个模型预测值和参考值问的相关系数分别为0.9800、0.9763和0.9853,预测均方根误差分别为0.3509、0.1147和0.1365.研究结果表明,近红外光谱技术可成功地检测茶叶中EGCG,ECG和EGC的含量.     

Characterization and quantification of chemical constituents in Fuzhuan brick tea using ultra-high-performance liquid chromatography–mass spectrometry

Fuzhuan brick tea, a distinctive dark tea fermented by microorganisms, is a traditional beverage in China throughout history. Recently, it has attracted considerable attention owing to its unique quality characteristics and potential health benefits. The aim of this study was to establish a method for the quality control of Fuzhuan brick tea for stable production. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was used to identify Fuzhuan brick tea, and the major components were chosen for further quantitative analysis. Subsequently, a quantification method was developed using ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry, and its reliability was verified through methodological validation. Finally, a total of 30 compounds were identified, including catechins, flavonoids, alkaloids, and fatty acids. The established method was reliable for methodological validation and was applied to the quantitative analysis of Fuzhuan brick tea. This study provides a fundamental basis for the quality control and further studies on the component analysis of Fuzhuan brick tea.     

常见茶叶中14种元素含量分析及重金属风险评价

采集传统名茶地标产品样品各3种为实验样品,通过ICP-OES和ICP-MS对样品进行K、Ca、Mg、Mn、B、Cu、Fe、Ni、Zn、Cr、Co、Cd、As、Pb等14种元素的含量测定.利用单因素方差分析、主成分分析、污染评价等方法,对茶叶无机元素含量进行分析和污染评价,并对污染来源进行了研究.结果表明,不同产地茶叶样...     

Development of a polyurethane-coated thin film solid phase microextraction device for multi-residue monitoring of pesticides in fruit and tea beverages

A novel solid-phase microextraction device coated with an efficient and cheap thin film of polyurethane was developed for trace determination of 13 widely used pesticides in fruit and tea beverages. A round-shaped polyurethane film covering the bottom of a glass vial was fabricated as the sorbent to exhibit a superior capacity for preconcentrating target compounds and reducing matrix interferences. After optimization of the key parameters including the film type, extraction time, solution pH, ionic strength, desorption solvent, and conditions, this device allowed an efficient adsorption-desorption cycle for the pesticides accomplished in one vial. Coupled with gas chromatography-electron capture detection, the polyurethane-coated thin film microextraction method was successfully established and applied for the analysis of real fruit and tea drinks, showing low limits of detection (0.001–0.015 μg/L), wide linear ranges (1.0–500.0 μg/L, r² > 0.9931), good relative recoveries (77.2%–106.3%) and negligible matrix effects (86.1%–107.5%) for the target pesticides. The proposed approach revealed strong potential of extending its application by flexibly modifying the type or size of the coating film. This study provides insights into the enrichment of contaminants from complex samples using inexpensive and reusable microextraction devices that can limit the environmental and health impact of the sample preparation protocol.     

Camellia sinensis: Insights on its molecular mechanisms of action towards nutraceutical,anticancer potential and other therapeutic applications

The Camellia sinensis plant provides a wide diversity of black, green, oolong, yellow, brick dark, and white tea. Tea is one of the majorly used beverages across the globe, succeeds only in the water for fitness and pleasure. Generally, green tea has been preferred more as compared to other teas due to its main constituent e.g. polyphenols which contribute to various health benefits. The aim of this updated and comprehensive review is to bring together the latest data on the phytochemistry and pharmacological properties of Camellia sinensis and to highlight the therapeutic prospects of the bioactive compounds in this plant so that the full medicinal potential of Camellia sinensis can be realised. A review of published studies on this topic was performed by searching PubMed/MedLine, Scopus, Google scholar, and Web of Science databases from 1999 to 2022. The results of the analysed studies showed that the main polyphenols of tea are the four prime flavonoids catechins: epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC) along with the beneficial biological properties of tea for a broad heterogeneity of disorders, including anticancer, neuroprotective, antibacterial, antiviral, antifungal, antiobesity, antidiabetes and antiglaucoma activities. Poor absorption and low bioavailability of bioactive compounds from Camellia sinensis are limiting aspects of their therapeutic use. More human clinical studies and approaching the latest nanoformulation techniques in nanoparticles to transport the target phytochemical compounds to increase therapeutic efficacy are needed in the future.