大气中氟污染对牡丹影响的调查分析

对大气氟污染与观赏植物牡丹叶片中的含氟量之间的关系进行了分析。结果表明：(1)一定时间内牡丹叶片的吸氟量和积累量成正相关。(2)牡丹叶片中的含氟量与测定点距污染源的距离呈负相关。(3)牡丹叶尖枯病是因大气氟污染所致，并非病理原因。     

Ratiometric electrochemical,electrochemiluminescent, and photoelectrochemical strategies for environmental contaminant detection

Global environmental pollution issue has boosted the development of novel analytical techniques with high efficiency and accuracy for detection of hazardous contaminants. Strategies based on electrochemical, electrochemiluminescent, or photoelectrochemical analysis are among the promising detection approaches to provide rapid and sensitive analysis. Currently, combining ratiometric assay with such strategies can further promote their sensing reliability and reproducibility in complex conditions. This review highlights recent advances of ratiometric electrochemical, electrochemiluminescent, and photoelectrochemical sensors in the past 2 years. Their signal generation strategies and analysis applications, particularly for the environmental contaminant detection, are discussed in detail, and a future prospect in this area from us is also provided.     

流动注射化学发光法测定茶饮料中的茶多酚

在碱性条件下,茶多酚对鲁米诺-KMnO4化学发光体系具有较强的抑制作用,据此建立了茶多酚的流动注射化学发光测定法。该法的化学发光抑制值ΔICL与茶多酚质量浓度在2.0×10-6~5.0×10-4mg/mL范围内,呈现出良好的线性关系,检出限为1.2×10-7mg/mL,对1.0×10-5mg/mL茶多酚测定的相对标准偏差为2.9%(n=11)。用于茶饮料中茶多酚的测定。     

Bubble-point measurements for the system CO2 + aqueous ethanol solutions of boldo leaf antioxidant components (boldine and catechin) at high pressures

The bubble-points pressures of solute(s) + ethanol + water + CO₂ mixtures were determined visually using a synthetic method in an experimental apparatus that included a variable-volume equilibrium cell. Tested solutes included boldo leaf tincture, a boldine + catechin mixture, pure boldine, and pure catechin. Uncertainties in bubble-point pressures were estimated to be <5%, based on comparisons with literature values and replicate measurements. The largest effect we observed was an average increase of 205% in the bubble-point pressure when decreasing the ethanol-to-water ratio from 63:37 to 37:63 (w/w). The bubble-point pressure increased 11% when increasing the temperature from 313 to 343 K, and decreased 8.2% when increasing the concentration of solids from 400 to 1500 ppm. The bubble-point pressure was higher for boldo leaf tincture than for a boldine + catechin mixture having the same boldine-to-catechin weight ratio, but this was partially due to a lower content of solids in the tincture. On the other hand, bubble-point pressures of the boldine + catechin mixture were marginally (0.33%) higher than the weighed average of the bubble-point pressures for pure boldine and pure catechin.     

差示分光光度法测定茶多酚的含量

基于茶多酚在酸性条件下还原 Fe3+ 为 Fe2 + ,Fe2 + 与铁氰化钾生成可溶性兰色配合物 KFe[Fe (CN) 6 ],用差示分光光度法测定其吸光度 ,从而可间接测定茶多酚的含量。方法线性范围为 2μg/m L～ 1 2μg/m L ,ε=1 .97× 1 0 5L· mol- 1· cm- 1,RSD=1 .3 % (茶多酚含量 8μg/m L,n=1 1 )。测定结果与标准方法基本一致     

全二维气相色谱/飞行时间质谱用于烟叶中酸性成分的分离与分析

建立了烟叶中酸性化合物(挥发性、 半挥发性羧酸类和酚类)组成研究的全二维气相色谱/飞行时间质谱(GC×GC-TOFMS)分析方法, 并用此方法对香料烟中的酸性化合物进行了表征. 用同时蒸馏萃取样品的前处理方法, 采用TOFMS谱图库检索结合全二维特有的包含结构信息的二维谱图, 通过族分离和结构谱图, 鉴定出了香料烟中143种挥发性及半挥发性酸性组分, 包括10种酸酐和呋喃二酮, 43种有机酸和90种酚类化合物. 同时对不同类别的化合物在二维气相色谱上的分布模式进行了研究. 结果表明, 全二维气相色谱飞行时间质谱的高分辨率非常适合于烟叶这类复杂体系的分离分析.     

全二维气相色谱/飞行时间质谱(GC×GC/TOFMS)用于烟叶中挥发、半挥发性碱性化合物的组成研究

建立了烟叶中挥发性、半挥发性碱性化合物组成研究的全二维气相色谱/飞行时间质谱(GC×GC/TOFMS)分析方法, 并用所建立的方法对香料烟中碱性化合物进行了表征. 对比了一维气相色谱和全二维色谱方法用于烟叶碱性组分组成分析的效果. 一维色谱质谱方法共鉴定出45种碱性化合物. 用所建立的全二维气相色谱方法, 采用TOFMS谱图库检索结合全二维特有的包含结构信息的二维谱图, 通过族分离和结构谱图鉴定, 鉴定出了香料烟中挥发性、半挥发性碱性组分共92种. 包括吡咯类化合物6种, 吡啶类化合物39种, 吡嗪类化合物10种, 苯胺类化合物11种, 喹啉类化合物11种, 吲哚类4种和其他类化合物11种. 同时对不同类别的化合物在二维气相色谱上的分布模式进行了研究. 研究结果表明, 全二维色谱飞行时间质谱的高分辨率和特有的定性手段适合于烟叶这类复杂植物体系的化学组成研究.     

Characterization of polyphenols from plant materials through their silylation and 29Si NMR spectroscopy-line assignment through 29Si, 13C spin-spin couplings

The lines in (29)Si NMR spectra of silylated polyphenols and some other compounds are difficult to assign owing to the absence of couplings with protons outside the silyl group. The assignment can be derived through small (n)J((29)Si, (13)C) couplings (n > 1). Using a previously described method for measurements of these couplings, the assignment procedure is demonstrated here on three examples of trimethylsilylated phenols: 7-hydroxyflavone, ferulic acid, and quercetin. In some cases the procedure can be used to identify carbon atoms to which the siloxy groups are attached.     

The stability of foliations of orientable 3-manifolds covered by a product

We examine the relationship between codimension one foliations that are covered by a trivial product of hyperplanes and the branched surfaces that can be constructed from them. We present a sufficient condition on a branched surface constructed from a foliation to guarantee that all perturbations of the foliation are covered by a trivial product of hyperplanes. We also show that a branched surface admits a strictly positive weight system if and only if it can be constructed from a fibration over .

     

树脂法提取茶多酚的研究

本文研究了用大孔吸附树脂由茶叶提取茶多酚的方法。通过对树脂的筛选，确定了NK-S3树脂对茶多酚吸附-解吸性能良好；选择由乙醇、乙酸乙酯和水组成的混合液为脱附剂；研究了流速对吸附、脱附性能的影响，并解决了茶水的前处理问题。