Synthesis,characterization and antioxidant,antibacterial activity Zn2+, Cu2+, Ni2+ and Co2+, complexes of ligand [2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzo[d]imidazole]

New metal complexes of (Zn(II), Co(II), Ni(II) and Cu(II)) based on the ligand 2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzo[d]imidazole] were synthesized, whose structures were determined with the different spectroscopic techniques ¹H NMR,¹³C NMR, FT-IR, UV–Visible and by mass spectrometry. The thermal analysis was performed by TG-DTA. The antioxidant activity of the ligand and its complexes was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) method, in comparison with the synthetic antioxidant, ascorbic acid. The results obtained showed that the antioxidant activity of the ligand and its complexes is moderate and that the copper complex has a high activity that exceeds that of ascorbic acid. Antimicrobial activity of the ligand and its metal complexes was studied against two Gram-positive bacteria: Bacillus subtilis ILP1428B, Staphylococcus aureus CIP543154 and two Gram-negative bacteria: Pseudomonas aeruginosa ATCC27653, Escherichia coli CIP5412 (American Type Culture Collection)the activity data show that the metal complexes are more potent than the free ligand.     

固相萃取-毛细管柱气相色谱-质谱测定土壤和蔬菜中三唑酮残留量

提出固相萃取分离,毛细管柱气相色谱和质谱联用法测定土壤及蔬菜中三唑酮的残留量.试样用乙腈提取,所得提取液在80℃吹氮至近干,并加正己烷2 mL溶解残渣.此溶液流经填充酸性氧化铝的固相萃取小柱,用正己烷-丙酮(2+1)混合溶剂淋洗小柱,使土壤样品中存在的硫磺与需测定的三唑酮分离.用正己烷一丙酮(1+3)混合溶剂将三唑酮从小柱上解吸洗下,所得洗出液蒸发浓缩,用正己烷定容为5.0 mL供GC-MS分析用.测定中用三唑酮标准溶液制备浓度范围在0.006～1.44 mg·L-1之间的标准曲线.方法的检出限(3S/N)为0.001 mg·kg-1.在3个浓度水平上对方法的回收及精密度作了试验,测得其回收率及相对标准偏差(n=5)依次在84%～92 9,5及1.93%～4.04%之间.     

Differential non-destructive image current detection in a fourier transform quadrupole ion trap

Dual-detector differential non-destructive Fourier transform detection in a quadrupole ion trap is shown to improve signal intensity and reduce noise compared with spectra recorded using a single detector. A larger area detector in each end-cap electrode is machined to fit its hyperbolic shape and so minimize field imperfections on the z-axis. Argon, acetophenone and bromobenzene spectra were recorded to allow a comparison between single- and dual-detector (differential) modes of detection and to demonstrate the improvement achieved with differential detection. Copyright 1999 John Wiley & Sons, Ltd.     

Determination of Methanol Increment in Mobile Phase Consisting of Methanol and Water by On—line UV Spectrometry in Reversed Phase Liquid Chromatography

ＩｎｔｒｏｄｕｃｔｉｏｎＦｒｏｎｔａｌｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＦＣ) ,ａｎｏｌｄｂｒａｎｃｈｉｎｌｉｑｕｉｄｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＬＣ) ,1ｈａｓｂｅｅｎｓｕｃｃｅｓｓｆｕｌｌｙｅｍ ｐｌｏｙｅｄｉｎｔｈｅｓｏｌｕｔｉｏｎｏｆｍａｎｙｔｈｅｏｒｅｔｉｃａｌａｓｗｅｌｌａｓａｐ ｐｌｉｅｄｐｒｏｂｌｅｍｓ—ｓｕｃｈａｓｍｅａｓｕｒｉｎｇｂｉｎｄｉｎｇｃｏｎｓｔａｎｔｂｅ ｔｗｅｅｎｃｏｍｐｏｎｅｎｔｓ2 ａｎｄｋｉｎｅｔｉｃｐａｒａｍｅｔｅｒｓｏｆｃｈｅｍｉｃａｌｒｅａｃｔｉｏｎｓ ,3 ａｄｓ…     

乙基曙红碘翁盐的染料再生循环光敏体系

本文设计了染料循环再生的光敏反应体系, 通过对占吨碘翁盐电子反应机制的深入研究, 提出了占吨染料在光敏反应过程中的染料再生循环, 它依次由三个反应过程组成: 在光作用下, 通过电子转移反应, 产生染料氧化褪色体(I); 在H给体存在下, 通过H转移反应, 使产物(I)转化为染料酸式隐色体(II); 在碱作用下, (II)发生去质子反应, 染料再生回复到染料的起始结构。其中光、H给体和碱的作用是再生循环的三个要素, 而控制染料酸式隐色体生成比例是染料再生效率的关键。由乙基曙红碘翁盐/三乙胺组成的染料再生体系的染料敏化效率比单一体系高4倍左右, 同时使活性自由基的数量增殖, 这种体系在实际应用方面具有重要意义。     

High-precision determination of the 13CO2/12CO2 isotope ratio using a portable 2.008-μm diode-laser spectrometer

A compact and portable diode-laser spectrometer is developed for high-precision measurements of the ¹³CO₂/¹²CO₂ isotope ratio. Ro-vibrational transitions belonging to different combination bands, around 2.008 m, are detected for the two isotopomers, using wavelength-modulation spectroscopy with first-harmonic detection. The determination of the isotope ratio is performed through a comparison between the spectra, simultaneously acquired in two different multiple-reflection cells designed to contain the sample and reference gases. The reproducibility of our method is extensively investigated over different time scales. In particular, the short-term precision of the isotope ratio determination is found to be 0.03%. We discuss the presence of possible systematic shifts in the -v alue and optimise the operating conditions to ensure accuracy within the precision level. A possible use for in-situ measurements in volcanic gases is also discussed. PACS 42.62.Fi; 42.55.Px; 33.20.Ea     

Measuring delta13C of atmospheric air with non-dispersive infrared spectroscopy

The potential use of non-dispersive infrared spectroscopy for measuring delta(13)C in air is demonstrated. This technique has already been successfully established for breath test analyses in medical diagnostics, where the CO(2) concentration ranges from 1 to 5 vol.% in the exhaled breath of vertebrates. For breath tests, the sensitivity and accuracy has been improved to reach a standard deviation of 0.2 per thousand (delta-value). Further adjustments were necessary to improve the sensitivity of the instrument at concentration levels typical of atmospheric air. The long-term stability is given by a standard deviation of 0.35 per thousand for CO(2) concentrations of about 400 ppm with signal averaging over 60 s.     

Analysis of some large-scale nonlinear stochastic dynamic systems with subspace-EPC method

The probabilistic solutions to some nonlinear stochastic dynamic (NSD) systems with various polynomial types of nonlinearities in displacements are analyzed with the subspace-exponential polynomial closure (subspace-EPC) method. The space of the state variables of the large-scale nonlinear stochastic dynamic system excited by Gaussian white noises is separated into two subspaces. Both sides of the Fokker-Planck-Kolmogorov (FPK) equation corresponding to the NSD system are then integrated over one of the sub...