分散固相萃取净化超高效液相色谱串联质谱法研究茶叶与茶汤中茚虫威残留降解规律

利用分散固相萃取净化茶叶、固相萃取富集净化茶汤,超高效液相色谱串联质谱法测定,建立了茶叶和茶汤中茚虫威残留的分析方法,并研究了150 g/L茚虫威乳油在茶园茶叶中的残留降解规律,对茚虫威在茶叶-茶汤过程中的浸出率和饮用安全性进行风险评估。结果表明:茚虫威在0.01～20.0 mg/L浓度范围内呈线性,其相关系数(r)为0.993 7,仪器检出限(LOD)为0.025 ng,在高、中、低3种水平下的平均加标回收率为96%～107%,RSD(n=6)为1.3%～7.8%,茚虫威在茶鲜叶、成茶中的定量下限(S/N=10)为5μg/kg,茶汤中的定量下限为0.10μg/L;150 g/L茚虫威乳油在茶园鲜叶上的半衰期为1.42～2.47 d;茚虫威在成茶-茶汤过程中的3次总浸出率小于10%,茶汤中茚虫威残留量及浸出率随冲泡次数的增加逐渐下降,按照风险评估制定茶叶中茚虫威残留量MRL值为3 mg/kg是安全的,人体摄入的茚虫威残留量仅占每日允许摄入量(ADI)的0.619%。     

气相色谱-质谱法测定荷兰豆中氟硅唑、丙环唑、苯醚甲环唑残留量

试样经乙腈提取,Dual Layer ENVITM-CarbⅡ/PSA(500/500 mg)固相萃取柱净化,选择离子监测/全扫描(SIM/SCAN),同时采集气相色谱-质谱法(GC-MS)对荷兰豆中氟硅唑、丙环唑、苯醚甲环唑残留量进行定性定量分析,方法检出限分别为0.001,0.003,0.005 mg.kg-1,在0.01,0.02,0.05 mg.kg-1添加水平回收率分别为60%~120%,70%~112%,75%~110%,相对标准偏差为5.0%~12.0%。     

苯醚甲环唑在香蕉和土壤中的残留分析方法研究

建立了苯醚甲环唑在香蕉和土壤中的残留分析方法。样品经乙腈或丙酮、乙酸乙酯提取,中性氧化铝柱净化,GC-ECD检测。方法在0.004~0.4μg/mL范围内有良好的线性关系,香蕉和土壤中苯醚甲环唑最低检测质量分数为0.004 mg/kg。样本中添加量为0.004~1.0 mg/kg时(n=5),平均回收率为81.4%~106.3%,相对标准偏差为1.5%~11%;方法的准确度和精密度均满足农药残留分析的要求。     

气相色谱-负化学离子源质谱法检测食品中苯醚甲环唑的残留量

建立了一种用于各种食品中苯醚甲环唑残留量的气相色谱-负化学离子源质谱(GC-MS/NCI)检测方法。用乙酸乙酯对各类样品中的苯醚甲环唑进行提取,固相萃取(SPE)净化后由GC-MS/NCI在选择离子监测模式下进行测定。方法的准确度和精密度高,多数样品在0.01,0.04,0.10 mg/kg三个添加水平下苯醚甲环唑的回收率处于70%和120%之间,相对标准偏差（RSD）不大于9.5%。方法在0.02～1.00 mg/L范围内有良好的线性关系,且灵敏度高,最低检测限达到0.0005 mg/kg;选择性好,抗干扰能力强,能消除复杂基质带来的干扰,适合各种食品中苯醚甲环唑残留量的确证分析。     

苯醚甲环唑在芹菜及其土壤中的残留测定和消解动态研究

采用气相色谱-电子捕获检测, 对芹菜及其土壤中的苯醚甲环唑消解动态和最终残留量进行了研究, 评价了苯醚甲环唑在芹菜上使用后的残留行为和环境安全性. 苯醚甲环唑在芹菜及土壤中的残留消解动态均符合一级动力学方程, 苯醚甲环唑在芹菜上消解快; 苯醚甲环唑最终残留量与施药的剂量、施药次数及采样的间隔时间有关; 水解研究表明, 苯醚甲环唑是稳定的农药, 在不同温度和不同pH的研究条件下水解半衰期均大于166 d, 碱性条件更有利于苯醚甲环唑的降解.     

气相色谱法同时测定蔬菜及水果中多种农药残留量

建立了蔬菜中乙草胺、甲草胺、苯氧菊酯、多效唑、环氟菌胺、氟虫腈、咪唑菌酮、氯菊酯、氟氯氰菊酯、高效氯氰菊酯、高效氰戊菊酯、丙炔氟草胺、茚虫威残留量气相色谱同时分析方法。采用分散固相萃取技术,在提取液中加入C18、石墨炭黑、PSA等吸附剂粉末进行净化,根据检测器选择溶剂置换,采用DB-1701毛细管柱分离,μECD检测。13种农药的浓度范围在0.002～0.05mg/kg时,回收率在80%～100%之间、RSD为1%～6%。各农药的检出限为:氟虫腈、环氟菌胺0.002mg/kg;苯氧菊酯、甲草胺、乙草胺0.004mg/kg;多效唑、咪唑菌酮、氯菊酯、氟氯氰菊酯、高效氯氰菊酯、高效氰戊菊酯、丙炔氟草胺、茚虫威0.01mg/kg。该方法步骤简单,净化效果好,具有良好的灵敏度、回收率和重现性。     

高效液相色谱-串联质谱法测定荔枝花粉和花蜜中腈菌唑和苯醚甲环唑残留

采用改良的QuEChERS-高效液相色谱-串联质谱（HPLC-MS/MS）技术,建立了荔枝花粉和花蜜中2种主要杀菌剂腈菌唑和苯醚甲环唑的测定方法。花粉和花蜜样品均由乙腈提取,花粉样品经0.9 g无水硫酸镁、0.15 g N-丙基乙二胺（PSA）和0.15 g十八烷基键合硅胶（C₁₈）吸附剂净化,花蜜样品由0.9 g无水硫酸镁和0.15 g PSA净化。采用Poroshell-120 EC-C₁₈色谱柱分离,以0.1%（v/v）甲酸水溶液-乙腈（25∶75,v/v）为流动相等度洗脱,在电喷雾离子（ESI）源、正离子扫描和选择离子监测模式下进行检测,基质匹配标准溶液法定量。结果显示：腈菌唑和苯醚甲环唑在1~100 μg/L范围内线性关系良好,相关系数（r²）均大于0.9990;腈菌唑和苯醚甲环唑的检出限（LOD）分别为0.25 μg/kg和0.50 μg/kg,定量限（LOQ）分别为0.83 μg/kg和1.7 μg/kg;腈菌唑和苯醚甲环唑在荔枝花粉和花蜜样品中的平均加标回收率分别为87.0%~95.2%和90.1%~96.4%,相对标准偏差（RSD）分别为1.2%~3.6%和0.7%~4.1%。该法快速、简便、灵敏,可用于荔枝花粉和花蜜样品中腈菌唑和苯醚甲环唑的痕量测定,可为蜜蜂等授粉昆虫的暴露性风险评估提供技术支持。     

高效液相色谱-三重四极杆质谱法测定稻虾综合种养环境中苯醚甲环唑和丙环唑残留量

建立了稻虾环境中水体、底泥、水草、饲料和克氏原螯虾肌肉、鳃丝和肝胰腺等组织中苯醚甲环唑和丙环唑的高效液相色谱-三重四极杆质谱(HPLC-MS/MS)检测方法。水体采用HLB固相萃取小柱富集;其余样品用乙腈∶水(4∶1, V/V)提取,并用石墨化炭黑(GCB),乙二胺-N-丙基硅烷(PSA)和中性氧化铝小柱对萃取液进行净化。采用正离子模式扫描,多反应监测模式(MRM)检测。苯醚甲环唑和丙环唑在1～50μg/L范围内线性关系良好,相关系数分别为0.9998和0.9995,仪器检出限为0.5μg/L,仪器定量限为1.0μg/L;底泥、水草、饲料、肌肉、鳃丝和肝胰腺样品的方法检出限为0.5μg/kg,方法定量限为1.0μg/kg,水体样品方法检出限和定量限分别为5.0×10^-3μg/L和1.0×10^-2μg/L。不同基质中分别添加低、中、高浓度的苯醚甲环唑和丙环唑,回收率分别在82.4%～104.8%和80.5%～110.9%,相对标准偏差(RSD)均在15%以内。     

固相萃取/高效液相色谱法对火龙果中手性苯醚甲环唑的分离测定

建立了固相萃取/高效液相色谱测定火龙果中手性苯醚甲环唑的方法。火龙果样品经乙腈提取,石墨化炭黑/氨基固相萃取柱净化后进行测定。实验考察了不同手性色谱柱、流动相组成、流速及进样体积对分离的影响,通过优化分离成功拆分了苯醚甲环唑对映体。优化的色谱条件为:Chrialcel IF-3手性柱为色谱柱,正己烷-乙醇(92∶8,体积比)为流动相,流速为1.0 m L/min,进样量为60μL。在上述条件下,4个对映体基本完全分离,分析时间不超过35 min。单个对映体在0.10~10 mg/L范围内呈良好的线性关系,检出限为0.025 mg/L。分别添加0.4、2.8 mg/kg两个水平的外消旋苯醚甲环唑,测得4个对映体的平均回收率分别为83.7%~99.3%和86.4%~91.6%,相对标准偏差分别为1.3%~7.2%和1.4%~3.1%。该方法的分离时间较短,分离效果好,灵敏度高,适用于火龙果等水果中手性农药苯醚甲环唑含量的测定。     

超高压液相色谱串联质谱法测定小油菜中3种农药残留EI北大核心CSCD

建立了小油菜中阿维菌素、氯虫苯甲酰胺和苯醚甲环唑3种农药残留的超高效液相色谱-串联质谱检测方法。样品经乙腈提取,SPE氨基固相萃取柱净化,超高效液相色谱-串联质谱(UPLC-MS/MS)同时进行检测。3种农药在小油菜样品中均存在程度不同的基质效应,因此,采用空白基质匹配的校准曲线外标法定量。3种农药均在0.5~500μg/L范围内具有良好的线性关系,相关系数均大于0.9996。在0.02~0.2 mg/kg范围内,平均添加回收率为84.0%~110.0%,相对标准偏差为1.2%~1.5%。阿维菌素、氯虫苯甲酰胺和苯醚甲环唑的检出限(LOD)分别为1.87,0.0115和0.0110μg/kg,定量限(LOQ)分别为6.24,0.0384和0.0366μg/kg。     

天然抗氧化剂茶多酚

抗氧化剂是指能防止或延缓食品成分氧化变质的食品添加剂.茶多酚是目前尚不能人工合成的纯天然、多功能、高效能的抗氧化剂和自由基净化剂,可用超临界CO2萃取法、离子沉淀提取法、树脂吸附分离法、有机溶剂萃取法提取.采用酒石酸亚铁比色法测定茶多酚含量.     

Significant Inactivation of SARS-CoV-2 In Vitro by a Green Tea Catechin,a Catechin-Derivative,and Black Tea Galloylated Theaflavins

Potential effects of tea and its constituents on SARS-CoV-2 infection were assessed in vitro. Infectivity of SARS-CoV-2 was decreased to 1/100 to undetectable levels after a treatment with black tea, green tea, roasted green tea, or oolong tea for 1 min. An addition of (−) epigallocatechin gallate (EGCG) significantly inactivated SARS-CoV-2, while the same concentration of theasinensin A (TSA) and galloylated theaflavins including theaflavin 3,3′-di-O-gallate (TFDG) had more remarkable anti-viral activities. EGCG, TSA, and TFDG at 1 mM, 40 µM, and 60 µM, respectively, which are comparable to the concentrations of these compounds in tea beverages, significantly reduced infectivity of the virus, viral RNA replication in cells, and secondary virus production from the cells. EGCG, TSA, and TFDG significantly inhibited interaction between recombinant ACE2 and RBD of S protein. These results suggest potential usefulness of tea in prevention of person-to-person transmission of the novel coronavirus.     

茶与化学

饮茶在我国有数千年历史 ,且经久不衰 ,现在几乎普及至世界所有国家和地区 ,这是基于茶叶中含有 6 0 0多种化学成分 ,其中大多数成分对人体有营养保健作用以及对许多疾病有预防和治疗功效。     

Tea and fluorosis

Tea trees (Camellia sinensis), abundant in fluoride, selectively absorb F from the soil and air in the surrounding, and accumulate mainly in the tea leaves in the form of Al and F complex. Long-term consumption of high fluoride tea could result in chronic fluoride intoxication. This review summarized those data of the fluoride content in various tea commodities, and estimated the risk of fluorosis caused by high fluoride tea commodities. We also introduced fluorosis caused by tea from case reports, epidemiology observations and animal models. Fluorosis was easily misdiagnosed and over-looked and people made little acquaintance in the high fluoride in some tea commodities. So it is the time to pay more attentions on the over-looked safety problem of tea and tea products and some measures should be taken to the fluorosis caused by tea. Large-scale epidemiological investigations and further studies on tea-type fluorosis are in need for those tea-drinking areas. In addition, it is urgent that governmental and international agencies adopt safe standards of fluoride content in tea commodities.     

Speciation of Manganese in Tea Leaves and Tea Infusions

Abstract

A speciation scheme was developed for identification of the chemical forms of manganese in tea leaves and tea infusions. The range of manganese in five different groups of tea leaves was found to be 1107 – 2205 μg/g on a dry basis. It was noted that 30.0% of Mn was passed into the water that was present in the form of Mn(II), and also 2.5% of Mn was found as the total organic bound fraction and passed into the various solvents.     

茶业风云——茶多酚

Tea polyphenols are the main active substances in pu-erh tea. They play an important role in anti-tumor, anti-virus, and antioxidant activity, as well as preventing senile cardiovascular and cerebrovascular diseases. In this paper, we, in a hint fiction, introduced the basic properties, physiological functions of tea polyphenols and described the effect of production technology on the content of tea polyphenols.     

高效液相色谱法测定绿茶中茶多酚及咖啡因

应用高效液相色谱法测定绿茶中没食子酸(GA)、咖啡因(CAF)及5种儿茶素类化合物,包括儿茶素(C)、表儿茶素(EC)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)、没食子儿茶素没食子酸酯(GCG)。对国家标准方法GB/T 8313-2008中流动相组成进行了调整,用0.5%乙酸代替2%的乙酸,在AT.Lichrom ODS色谱柱(4.6mm×250mm,5μm)上进行分离,流量为1.0mL.min-1,在波长278nm处进行紫外检测。7种组分在40min内达到完全分离。7种组分的质量浓度分别在一定的范围内与其峰面积呈线性关系。方法用于绿茶的分析,7种组分的加标回收率在96.0%～102.8%之间。     

Accumulation of Dieldrin,Heptachlor and DDT on Tea Leaves

Tea leaves grown in a field that had been treated in the nearby top soil with 75% DDT 1kg per hectare, 50% Dieldrin 10kg per hectare, or 2.5% Heptachlor 50kg per hectare were analyzed separately. Dieldrin residues accumulated to a maximum of over 0.20ppm. DDT and both Heptachlor and its metabolite, Heptachlor Epoxide, were much lower than that of Dieldrin, with only a few samples detectable.     

Correlation among Metabolic Changes in Tea Plant Camellia sinensis (L.) Shoots,Green Tea Quality and the Application of Cow Manure to Tea Plantation Soils

Traditionally, the supplement of organic manure in tea plantations has been a common approach to improving soil fertility and promoting terroir compounds, as manifested by the coordinated increase in yield and quality for the resulting teas. However, information regarding the effect of organic manure in the metabolome of tea plants is still inadequate. The metabolite profiles of tea shoots applied with cow manure, urea or no fertilizer were studied using gas chromatography–mass spectrometry (GC–MS). In total, 73 metabolites were detected, and the modulated metabolites included mainly amino acids, organic acids and fatty acids. In particular, glutamine, quinic acid and proline accumulated more in tea shoots in soils treated with cow manure, but octadecanoic acid, hexadecanoic acid and eicosanoic acid were drastically reduced. Pearson correlation analysis indicated that organic acids and amino acids in tea shoots were the two major metabolite groups among the three treatments. The analysis of metabolic pathways demonstrated that the cow manure treatment significantly changed the enrichment of pathways related to amino acids, sugars and fatty acids. Sensory evaluation showed that the quality of green teas was higher when the plants used to make the tea were grown in soil treated with cow manure rather than urea during spring and late summer. The results indicated that the application of cow manure in soils changed the metabolic characteristics of tea shoots and improved the qualities of the resulting teas.     

茶多糖的提取纯化及其药理作用的研究进展

对茶多糖(TPS)的提取、分离纯化、药理作用等方面的研究进展进行了综述,对(TPS)的降血糖、防治糖尿病,以及降血脂、抗动脉粥样硬化、降血压、抗凝血、抗血栓、防治心血管疾病等作用作了评述。