Effect of moisture (in solid polymer electrolyte) on the photosensitivity of conducting polypyrrole sensitized by prussian blue in solid-state photocells

The effect of small concentration of dispersed prussian blue (PB) [in solid polymer electrolyte viz polyvinyl alcohol (PVA) with phosphoric acid] on the photocurrents were studied (in wet state and in dry state of solid polymer electrolyte) in solid state photocells fabricated using conducting polypyrrole (PPy). These exhibit good photoresponse to visible light: photocurrents being 20 to 25 times greater than the dark currents depending upon the concentration of the sensitizer. The current–voltage (I–V) characteristics in such cells reveals that the charge transport is mainly governed by the space charge effects and the sensitization effects are due to the lowering of the potential barrier formed at the polypyrrole (PPy)/polyvinyl alcohol (PVA) interface under photoexcitation. Also, sensitization effects were studied in the wet state and in dry state of solid polymer electrolyte (PVA). It has been observed that the moisture content in the solid polymer electrolyte reduces the photosensitivity factor (S=I_l/I_d, where I_l is the light current and I_d is the dark current), since it increases the ionic conductivity in the solid polymer electrolyte thereby increasing the dark current values which results in overall decrease in the photosensitivity factor (S). The importance of the other factors such as dye concentration, dye aggregation etc. have been explained on the basis of the experimental observations. The sensitization effects are explained on the basis of the energy band diagram of the materials forming the photocells.     

有机相阴离子交换SPE-UPLC-UV法快速测定食用植物油中的抗氧化剂TBHQ和BHA

建立了基于有机相阴离子交换SPE前处理的UPLC-UV法,快速测定食用植物油中的抗氧化剂TBHQ和BHA。食用植物油样品用正己烷稀释后,直接上样至Oasis MAX聚合物材质阴离子交换SPE柱中进行净化,用正庚烷淋洗去除甘油酯成分,用0.5%甲酸-四氢呋喃溶液洗脱。以纯水和甲醇为流动相,TBHQ和BHA在Eclipse Plus C18上和梯度洗脱条件下3.4 min内达到基线分离;检测波长为290 nm;进样量为1μL。TBHQ和BHA在5~200 mg/L范围内线性关系良好(r≥0.999 95);在10、50、200 mg/kg这3个水平的加标回收率为91.5%~104%,相对标准偏差为1.2%~4.4%。方法定量限为0.5 mg/kg。与已有方法相比,该方法样品前处理更简便快速、色谱分离时间短、结果准确,可广泛用于食用植物油样品中TBHQ和BHA等抗氧化剂的快速检测。     

动物肌肉、内脏和牛奶中咪唑脲苯残留量的高效液相色谱测定及液相色谱-串联质谱确证

目的建立固相萃取净化-高效液相色谱和液相色谱-串联质谱测定动物组织和牛奶中咪唑脲苯残留量的分析方法。方法残留的咪唑脲苯采用1%三氟乙酸-乙腈(1:4,v/v)提取,Oasis WCX固相萃取柱净化,高效液相色谱外标法定量,并经液相色谱-串联质谱确证。结果咪唑脲苯检出限为10μg/kg(S/N≥3),定量限为25μg/kg(S/N≥10);在LOQ、MRL和2MRL三个添加水平下重复分析6次,回收率为72.7%~101%,相对标准偏差为1.2%~6.9%。结论该方法稳定、可靠,适用于动物组织和牛奶中咪唑脲苯的测定。     

一株伯克霍尔德菌所产类细菌素的分离纯化

利用硫酸铵分级沉淀、固相萃取小柱层析、高效液相色谱分离的方法纯化一株伯克霍尔德菌所产类细菌素。结果表明,纯化效果较好,在保留时间5.783 min时出现一个较强的单一吸收峰,抑菌物质的最大吸收波长为223.06 nm,蛋白质含量为452 μg/mL。     

全二维气相色谱-飞行时间质谱分析直馏柴油馏分中硫化物的分子组成

The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compoundsin straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with a sulfur chemiluminescencedetector to harvest a satisfactory result. The identification of the structure of sulfur compounds by comprehensivetwo-dimensional gas chromatography coupled with the time-of-flight mass spectrometry indicated that cyclo-sulfides,benzothiophenes, dibenzothiophenes, dihydro-benzothiophenes and tetrahydro-dibenzothiophenes were included in straightrundiesel obtained from the Arab medium crude （AM）. A total of 259 individual compounds were detected and their molecularstructures were identified. The analytical method was approved as an effective way to characterize the composition ofsulfur compounds, which reduced the interference of other compounds, facilitated the data presentation and provided moredetailed information about molecular composition of sulfur compounds.     

固相萃取-液质联用测定辣椒粉中苏丹红

该试验建立了分子印迹固相萃取-超高效液相色谱-串联质谱法检测辣椒粉中苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ的方法。辣椒粉样品经过正己烷提取,氮吹浓缩,苏丹红专用分子印迹固相萃取柱净化和富集,以体积分数为0.2%的甲酸水溶液和乙腈为流动相梯度洗脱,经Agilent ZORBAX Eclipse Plus C₁₈(2.1 mm×50 mm,1.8μm)柱分离,ESI+电喷雾模式扫描,MRM多反应模式监测,外标法定量。结果显示,该方法下4种苏丹红的检出限均为5μg/kg,4种化合物在0~50μg/L质量浓度范围内线性关系良好,相关系数均在0.9990以上;当加标浓度为10,50和100μg/kg时,回收率在86.5%~102.2%之间,相对标准偏差均小于6.0%。该方法可为辣椒粉中4种苏丹红的定性定量分析提供参考。     

固相萃取-高效液相色谱法检测饮用水中痕量微囊藻毒素

介绍了建立固相萃取-高效液相色谱法检测水中痕量微囊藻毒素的方法。水样经固相萃取柱富集,净化,甲醇洗脱,氮吹浓缩,甲醇与磷酸盐缓冲溶液按45∶55混合作为流动相,色谱柱分离,检测用波长为238 nm。结果表明各组分在0~1μg/L内线性良好,平均回收率分别为100.9%和92%。该方法灵敏度高、操作简单、定量准确,适用于饮用水中痕量微囊藻毒素的检测。     

ANTARES: The first undersea neutrino telescope

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.     

HPLC determination of trimethoprim in meat and milk with an SPE preseparation procedure

 An HPLC method in combination with solid-phase extraction and dual wavelength detection has been developed in order to monitor trimethoprim residues in meat and milk. The extraction recoveries for the maximal residual limit concentration in food (50 ng/g) were 86±5% for meat and 73±6 % for milk samples. The limits of determination of trimethoprim were 5 ng/g at 229 nm and about 15 ng/g at 280 nm. The method has been developed in response to specific needs of food control laboratories. This publication introduces the assay for milk and meat samples. Received: 27 March 1996/Revised version: 23 July 1996     

Disruption of six Saccharomyces cerevisiae ORFs on chromosome XII results in three lethal disruptants.

Six ORFs of unknown function from the left arm of chromosome XII of Saccharomyces cerevisiae were chosen for a reverse genetic approach to provide materials to assist in assignment of function. A two-step PCR using long-flanking homology was employed to amplify disruption cassettes consisting of a kanMX gene as selectable marker flanked by 250-350 bp long regions homologous to the target gene. The diploid strains FY1679 and CEN.PK2 were transformed with the replacement cassettes and transformants were selected for geneticin (G418) resistance. Correct targeting of the replacement cassettes at the genomic locus was verified by Southern blot analysis with the kanMX gene as a probe. Disruption cassettes were cloned in pUG7 plasmid for systematic gene inactivation in other yeast strains and the cognate genes were cloned in pRS416 plasmid for gene complementation studies. Sporulation and tetrad analysis of heterozygous disruptants showed that three of the six ORFs [YLR141w (RRN5), YLR145w and YLR147c (SMD3)] were essential genes that were complemented by their cognate genes. ylr146c Delta (spe4) homozygous diploids showed enhanced sporulation efficiency, whereas ylr147c Delta heterozygous diploids failed to sporulate in the FY1679 but not in the CEN.PK2 genetic background. The other two disruptants [ylr143w and ylr144c (acf2)] gave no phenotype.