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.     

Synthesis,characterization, crystal structure and catalytic property of [Cu(SalAHE)2] (SalAHE = salicylaldehydeimine-1-hydroxyethane) complex for the oxidation of 3,5-di-tert-butylcatechol

The crystal structure, spectroscopic properties and catalytic property of the copper(II) complex, prepared by the reaction between copper(II) diacetate with the bidentate Schiff base, SalAHE (SalAHE = salicylaldehydeimine-1-hydroxyethane), are reported. This complex is able to oxidize 3,5-di-tert-butylcatechol to the respective o-quinone. The oxidation reaction was studied in CH₃CN with molecular oxygen at 0, 5, 15 and 25 °C. The progress of the catalytic reaction was followed by gas chromatographic analyses (GC).     

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.     

Voltammetric determination of pyridoxine (Vitamin B6) at a carbon paste electrode modified with vanadyl(IV)-Salen complex

The preparation and electrochemical characterization of a carbon paste electrode modified with the N,N-ethylene-bis(salicylideneiminato)oxovanadium(IV) complex [VO(Salen)] as well as its behavior in relation to the oxidation of pyridoxine (Vitamin B₆) are described. The electrochemical behavior of the modified electrode and the electrooxidation of pyridoxine were investigated using cyclic voltammetry. The best voltammetric response was obtained for an electrode composition of 15% (m/m) [VO(Salen)] in the paste, KCl solution of pH 5.5-8.0 and scan rate of 25 mV s⁻¹. A sensitive linear voltammetric response for pyridoxine was obtained in the concentration range of 4.5×10⁻⁴ to 3.3×10⁻³ mol l⁻¹ with a slope of 42.5 μA mmol⁻¹ l, and a detection limit (3σ/slope) of 3.7×10⁻⁵ mol l⁻¹ using linear sweep voltammetry. Among several compounds tested only Vitamin B₁ seems to interfere in the analyte signal. The concentrations of pyridoxine in pharmaceutical formulations using the proposed electrode and an official spectrophotometric method based in the reaction with N,N-diethyl-p-phenylenediamine are in agreement at the 95% confidence level and within an acceptable range of error.     

Thermal decomposition of complexes

The iron(II) complex of the Schiff bases trans-N,N'-bis(salicylidene)-1,2-cyclohexanediamine (Salcn), manganese(II) and vanadyl complexes of the Schiff bases cis- andtrans-N,N'-bis(salicylidene)-1,2-cyclohexanediamine (Salcn) were prepared and characterized by IR spectroscopy, and elemental analysis. These new complexes were submitted to thermal analysis (TG and DSC) under dynamic air atmosphere. The differences in the decomposition profiles were related to the structure of isomers and decomposition intermediates were characterized according to their X-ray diffraction pattern and by their infrared spectrum. This revised version was published online in August 2006 with corrections to the Cover Date.     

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…