Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresis

A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25 degrees C and 20 kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25-34 microg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1-5 mg/L. Determination of these analytes from abusers' urine sample was also demonstrated.     

Synthesis and Mesogenic Properties of Liquid Crystals Containing Terminal Cyclohexylmethanol,Cyclopentylmethanol, Cyclobutylmethanol and Cyclopropylmethanol Moiety

Four series of compounds 11?50 containing terminal alicyclic rings such as cyclohexylmethyl, cyclopentylmethyl, cyclobutylmethyl, and cyclopropylmethyl rings were synthesized and their liquid crystal behavior studied. The ring size and the length of flexible alkoxy chain influence the phase formation in different ways. While the smaller ring and the shorter alkoxy chain tend to favor the formation of the N phase, the larger ring and the longer alkoxy chain tend to favor the formation of the SmC phase. All the compounds except 11 and 21 exhibit SmA phases. The widest temperature range of the N, SmA, and SmC phases are found in the compounds 41 , 46 , and 20 , respectively, which are 75 °C for 41 , 115 °C for 46 , and 100 °C for 20 .     

火焰原子吸收光谱法测定天然水中微量铁的形态

研究了用抗坏血酸为还原剂,使二价铁离子与邻菲啰啉(phen)形成螯合物,用硝基苯萃取,火焰原子吸收光谱法测定有机相中的铁。方法检出限为1.7ng·ml~(-1),回收率为98.0％～109.6％,线性范围为0～10.0μg·ml~(-1)(原水相),线性相关系数为0.9994。测定结果与ICP-AES法结果对照相对误差小于9.46％。     

珠江广州河段水中有机污染物的GC-MS分析

用吹扫捕集、树脂富集珠江广州河段海印断面水中有机物，毛细管色谱柱分离，用气相色谱－质谱联用方法测定有机污染物的组成，从水中鉴定出60个有机物，并作了定量分析；结果表明有机物种类多，污染较严重。     

An organic-phase optical phenol biosensor coupling enzymatic oxidation with chemical reduction

This paper presents a recycle amplification optical biosensor to monitor phenol in hydrophobic organic solvents. Tyrosinase was first immobilised by entrapping it in a copolymer membrane of poly(vinyl alcohol)-hydroxyethyl carboxymethylcellulose doped with octadecylsilica particles. The biosensor was then constructed by co-mixing small particles of the immobilised tyrosinase with the adduct of L-ascorbic acid-poly(vinyl alcohol) (AsA-PVA) in conjunction with an optical oxygen transducer. The biosensor was characterised by its amplifying response to phenol, stable biocatalytic activity of entrapped-tyrosinase, free of interference from o-quinone polymerisation, and large water buffer capacity in hydrophobic organic solvents. The working range of the biosensor to phenol was 0.08-40 mmol dm(-3) in the flow mode. The response times (95%) of the biosensor were 4-7 min for phenol. The operational lifetime was more than 40 assays and the shelf lifetime of the biosensor was longer than 3 months. The biosensor has been successfully applied to quantify the phenol contents in some commercial ointment samples.     

2-巯基苯并咪唑保护的铜纳米团簇的制备及银离子检测

以2-巯基苯并咪唑为保护剂,聚乙烯吡咯烷酮为稳定剂,水合肼为还原剂,“一锅法”合成2-巯基苯并咪唑保护的,高稳定性、强荧光、大斯托克斯位移的铜纳米团簇(Cu NCs),并用于检测水样中的银离子含量。采用透射电子显微镜(TEM)和X射线光电子能谱(XPS)对铜纳米团簇的结构进行表征,通过荧光光谱和紫外可见光谱对其光学性能进行研究。研究表明:该铜纳米团簇的最大激发和发射波长分别为340和558 nm,在日光灯和紫外灯下分别为无色和橙色。Cu NCs具有较高的分散性,尺寸大小为2~3 nm。在最佳反应条件下,铜纳米团簇可以选择性地被银离子猝灭,且灵敏度高,线性范围为1~40μmol/L,检测限为0.5μmol/L。该方法用于检测实际水样(自来水、湖水)中银离子的浓度,结果令人满意,表明在环境监测中有非常高的应用价值。     

An in silico ensemble method for lead discovery: decision forest

Recent progress in combinatorial chemistry and parallel synthesis has radically changed the approach to drug discovery in the pharmaceutical industry. At present, thousands of compounds can be made in a short period, creating a need for fast and effective in silico methods to select the most promising lead candidates. Decision forest is a novel pattern recognition method, which combines the results of multiple distinct but comparable decision tree models to reach a consensus prediction. In this article, a decision forest model was developed using a structurally diverse training data set containing 232 compounds whose estrogen receptor binding activity was tested at the U.S. Food and Drug Administration (FDA)'s National Center for Toxicological Research (NCTR). The model was subsequently validated using a test data set of 463 compounds selected from the literature, and then applied to a large data set with 57,145 compounds as a screening example. The results show that the decision forest method is a fast, reliable and effective in silico approach, which could be useful in drug discovery.     

Recent progress in two-photon small molecule fluorescent probes for enzymes

This review aims to provide a summary of the progress in TP small molecule fluorescent probes for enzymes in recent years and displays the main fluorescent mechanisms that have been applied to design probes.     

水溶性高聚物的研究进展

自八十年代初，水溶性高聚物再次成为高分子科学研究热点，评述了水溶性高聚物，特别是疏水缔合型改性水溶性高聚物的最新进展。     

Efficient Debromination of Vicinal α，β—Dibromo Carboxylic Acid Derivatives with the Sm／HOAc System

The α，β vicinal dibrome carboxylic acid and its derivatives were debrominated with Sm/HOAc system to afford the corresponding cinnamic acid and its derivatives in good yields under mild conditions.