A Home-made Simple Set-up for Measurement of Electrochemical Surface Tension Spectrum on a Mercury Drop Electrode

A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltammetric study. A Yb(III)-NO2- catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.     

Turbulent Convective Heat Transfer and Pressure Drop of Graphene–Water Nanofluid Flowing Inside a Horizontal Circular Tube

Turbulent convective heat transfer of graphene–water nanofluids with various concentrations inside a uniformly heated circular tube is studied experimentally. For this purpose, experiments are conducted to measure thermal conductivity, viscosity, pressure drop, and heat transfer coefficient. Results show enhancement of thermal conductivity and moderate increment of viscosity with addition of low amounts of nanoparticles. Moreover, heat transfer coefficient shows relatively high augmentation, and pressure drop remains unchanged. The maximum enhancements are 10.30%, 4.95%, and 6.04% for thermal conductivity, viscosity, and heat transfer coefficient, respectively. UV–Vis spectroscopy results show that the nanofluids are highly stable.     

Liquid–Liquid Extraction of Organic Compounds into a Single Drop of the Extractant: Overview of Reviews

Single-drop microextraction (SDME) and hollow-fiber membrane microextraction (HFME) belong to methods of the liquid-phase microextraction preconcentration of organic compounds. These methods are characterized by the low consumption of organic solvents, high preconcentration factors, simplicity, low cost, ease of combination with various chromatographic methods; processes of preconcentration and sample injection are combined in a single device. Since the emergence of SDME (1996) and HFME (1999), a large number of versions have been developed that differ in the preconcentration technique, nature of the extractants used, and combinations with methods for the subsequent determination of the preconcentrated substances. The popularity of these methods among the analysts is evidenced by many reviews that we have summarized in this publication.

     

Adsorptive Stripping Voltammetry of 9‐Phenanthrol in the Presence of Copper at the Static Mercury Drop Electrode—Basis for Quantitative Determination of PAH Metabolite in Biological Materials

Abstract

The electrochemical behavior of 9‐phenanthrol in the presence of copper (II) at a static mercury drop electrode was investigated to provide the basis for development of an inexpensive, sensitive, and reliable method for determination of polycyclic aromatic hydrocarbon (PAH) metabolites in biological matrices. Optimum experimental conditions for analytical applications were obtained in 0.005 M NaOH solution using an accumulation potential of ?0.25 V, a scan rate of 5 mV. s^?1, a pulse height of 25 mV, and a differential pulse scan mode. The response of 9‐phenanthrol is linear over the concentration range 1.0–12.0 ppb. For an accumulation time of 5 minutes, the detection limit was found to be 0.2 ppb (1.03×10^?9 M). The more convenient relation to measure the 9‐phenanthrol in the presence of copper and other metals was also investigated. The utility of the method was demonstrated by the presence of 9‐phenanthrol in samples of sea water and human urine. Cyclic voltammetry was used to characterize the interfacial and redox behavior.     

Determination of Carbamate and Benzoylurea Insecticides in Peach Juice Drink by Floated Organic Drop Microextraction–High Performance Liquid Chromatography

Abstract

Floated organic drop microextraction (FDME)–high performance liquid chromatography (HPLC) has been developed for extraction and determination of carbamate and benzoylurea insecticide residues from peach juice drink samples. The components were separated by a Diamonsil C18 instrument (5 µm, 250 mm × 4.6 mm i.d.). The mobile phase was a mixture of acetonitrile, methanol, and water (the ratio of volume was 18:70:12). Factors relevant to the extraction efficiency were studied and optimized. The methodology exhibited good linearity between 0.01 and 10.0 µg/mL with a correlation coefficiency of 0.9999. The average recovery of pesticides ranged from 88.49% to 101.86%. The relative standard deviations (RSDs) (n = 6) were 1.99–3.47%.     

Synthesis and Antibacterial Activities of 4—Amino—3—（1—aryl—5—methyl—1,2,3—triazol—4—yl）—5—mercapto—1,2,4—triazoles／2—Amino—5—（1—aryl—5—methyl—1,2,3—triazol—4—yl）—1,3,4—

Treatment of 4-amino-3-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-5-mercapto-1,2,4-triazoles/2-amino-5-(1-aryl-5-methyl-1,2,3-triazole-4-yl)-1,3,4-thiadiazoles with benzaldehyde,acetone and ω-bromoacetophenone was tested and compared.The title compounds Schiff bases,amides,imidazolo [2,1-b]-1,3,4-thiadiazoles and 7H-s-triazolo[3,4-b]-1,3,4-thiadiazines have been confirmed by elemental analyses,^1H NMR,IR and MS spectra.All the compounds have also been screened for their antibacterial activities against B.subtilis,S.aureus and E.coli.     

Undistorted Cyclic Voltammograms at Scan Rates up to 2.5 MVs~(-1) through Positive Feedback Compensation of Ohmic Drop

Introduction Though being the simplest voltammetric technique, cyclic voltammetry provides lots of electrochemical information especially in the study of the thermody-namic and kinetic processes and the detection of elec-trogenerated transient intermediates.1 Clearly, the more rapid the scan rate is employed, the faster the reactions can be studied. Indeed, a timescale RT/Fν～25 ns of the Faradaic response will be reached corresponding to a scan rateνof 1 MVs-1, which means that the method…     

3,3—二甲基—9—（5,5—二甲基—3—羟基—2—环己烯—1—酮—2—基）—1—氧代—2 …

标题化合物Ｃ２３Ｈ２６Ｏ４是水杨醛与５，６－二甲基－１，３－环己二酮在Ｎ，Ｎ－二甲基甲酰胺中反应而得。结果通过单晶Ｘ－射线衍射法确定，其晶体属于单斜晶系，空间群Ｐ２１／ｃ，ａ＝７．０５６，ｂ＝２０．２６３，ｃ＝１３．６６５Ａ，β＝９３．３２，Ｖ＝１９５０．７Ａ＾３，Ｍｒ＝３６６．４６，Ｄｃ＝１．２４８ｇ／ｃｍ＾３，Ｚ＝４，μ（ＭＯＫα）＝０．８４ｃｍ＾－１，Ｆ（０００）＝７８４。晶体结构用直接法解     

Crystal Structure of 3,4—trans—4,5—trans—2—Amino—3—cyano—1,3—diethylox

3，4－反－4，5－反－2－氨基－3－氰基－1，3－二乙氧羰基－4，5－二（4－氯苯基）环戊烯     

Synthesis of 3—Biaryl—1—ferrocenyl—2—propene—1—ones

The novel structures of organometallic compounds 3-biaryl-1-ferrocenyl-2-propene-1-ones 5 were synthesized for nonlinear optical chromophores by Suzuki cross-coupling reaction.Their structures were determined with elemental analyses,^1H NMR spectra and ^13C NMR spectra.     

4—取代苯基—6—甲基—5—硫代—1,2,4—三嗪—3—酮的合成

合成了一系列新的４，６－二取代－５－硫代－１，２，４－三嗪－３－酮类化合物，并用元素分析、ＩＲ、＾１Ｈ ＮＭＲ及ＭＳ对其结构进行了表征。     

1—芳基—2—苯基—3—甲基—3—异丙基—2—氧代—1,4,2—二氮磷杂？…

利用取代苯基脲与苯基二氮化膦和３－甲基－２－丁酮进行的类Ｍａｎｎｉｃｈ反应合成了１５种新的１,４,２－二氮磷杂环戊－５－酮类化合物（２ａ－２ｏ）,其结构经＾１Ｈ ＮＭＲ,ＩＲ,ＭＳ和元素分析证实,根据ＮＭＲ谱分析,反应主要生成顺式几何异构体,除草活性测试表明,目标化合物对阔叶杂草具有很好的选择性草活性,并对其结构与除草活性关系进行了讨论。     

Crystal and Molecular Structure of N—Phenyl 1—Methoxycarbonylmethyl—3—benzyl—1,2,3,4—tetrahydro—4—oxo—1,3,2—benzodiazaphosphorin—2—thiocarboxamide 2—Oxide

1 INTRODUCTIONOrganophosphorus compounds are ubiquitous in nature and they have broad applications in the fields of agriculture and medicine. During the past two decades, (-ketophosphonates and their derivatives containing sulfur have attracted considerable attention because these compounds are endowed with special physical, chemical and pharmacological properties due to the proximity of the carbonyl and the phosphoryl groups[1～8]. In the study on new pharmacenticals and agrochemicals, th…     

4—取代苯基—6—叔丁基—5—硫酮—1,2,4—三嗪—3—酮的合成

含有1,2,4三嗪母体环的化合物与核糖连接后,能参与蛋白质分子的合成,改变蛋白质的分子结构,具有抗癌、抗病毒、抗菌及杀虫除草等多种药物活性。作为三嗪类化合物的重要分支,4,6二取代5硫酮1,2,4三嗪3酮由于合成及分离上的困难,目前研究得较少[1][2]。4位为芳香基、6位为叔...