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.     

Visible spectrophotometric and first-derivative UV spectrophotometric determination of rifampicin and isoniazid in pharmaceutical preparations

Two methods are described for the determination of rifampicin and isoniazid in mixtures by visible spectrophotometry and first-derivative ultraviolet spectrophotometry. The absorbance at 475 nm in buffer solution pH 7.4 was employed to determine rifampicin after applying the three-point correction technique between 420 and 520 nm, while the amplitude of the first-derivative spectrophotometric spectrum at 257 nm in HCl 0.012 M was selected for the determination of isoniazid. The methods are rapid, simple and do not require any separation step. The recovery average was 99.03% for rifampicin and 100.01% for isoniazid. The methods were applied to determine the two compounds in commercial capsules and compared with the official method of the USP XXIII with good agreement between the results.     

Comparison between capillary electrophoresis and liquid chromatography for the determination of diclofenac sodium in a pharmaceutical tablet

Two novel analytical methodologies using capillary electrophoresis (CE) and liquid chromatography (LC) were developed and compared for the determination of diclofenac sodium in commercial and simulated tablet formulations. The CE analysis was performed in a bare fused-silica capillary with 75 microm id and total length of 50 cm (28 cm to the detector) with a buffer solution of 20 mM sodium tetraborate, pH 9.23. The applied voltage was 20 kV, and acetaminophen was used as the internal standard (IS). The LC analysis was performed with a LiChrospher 100 RP-18 (5 microm) column and a mobile phase of methanol-diluted glacial acetic acid (0.3 parts in 2500; 75 + 25) at a flow rate of 0.9 mL/min with propylparaben as the IS. In both analyses, detection was by ultraviolet absorption at 276 nm. Under optimized conditions, the CE migration times for the diclofenac sodium standard and acetaminophen (IS) were 2.07 and 1.59 min, respectively, and the LC retention times for the diclofenac sodium standard and propylparaben (IS) were 3.98 and 2.26 min, respectively. The resolution and efficiency for CE were 14.2 and 1.6 x 10(5) plates/m, respectively, and for LC, 5.0 and 8.6 x 10(3) plates/m, respectively. Calibration curves of peak area versus concentration gave correlation coefficients of 0.9992 for CE and 0.9994 for LC. The limits of detection and quantitation were 8.40 and 25.46 microg/mL, respectively, for CE and 4.60 and 13.93 microg/mL, respectively, for LC. Coefficients of variation were 1.68 and 0.37% for CE and LC, respectively. Average recoveries obtained with CE and LC were 103.12+/-0.90 and 99.59+/-0.21%, respectively. Although both methodologies were shown to be suitable for the determination of diclofenac sodium in tablets, performing in a similar manner with regard to several aspects (linearity, recovery, and specificity), CE provided faster analysis and better column efficiency, whereas LC provided superior repeatability and sensitivity.     

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

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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...     

Determination of Vecuronium Bromide in Pharmaceuticals: Development, Validation and Comparative Study of HPLC and CZE Analytical Methods

Vecuronium bromide is a neuromuscular blocking agent used for anesthesia to induce skeletal muscle relaxation. HPLC and CZE analytical methods were developed and validated for the quantitative determination of vecuronium bromide. The HPLC method was achieved on an amino column (Luna 150 × 4.6 mm, 5 μm) using UV detection at 205 nm. The mobile phase was composed of acetonitrile:water containing 25.0 mmol L^?1 of sodium phosphate monobasic (50:50 v/v), pH 4.6 and flow rate of 1.0 mL min^?1. The CZE method was achieved on an uncoated fused-silica capillary (40.0 cm total length, 31.5 cm effective length and 50 μm i.d.) using indirect UV detection at 230 nm. The electrolyte comprised 1.0 mmol L^?1 of quinine sulfate dihydrate at pH 3.3 and 8.0% of acetonitrile. The results were used to compare both techniques. No significant differences were observed (p > 0.05).     

Evaluation of carbonic anhydrase and paraoxonase inhibition activities and molecular docking studies of highly water-soluble sulfonated phthalocyanines

The investigation of carbonic anhydrase and paraoxonase enzyme inhibition properties of water-soluble zinc and gallium phthalocyanine complexes ( 1 and 2 ) are reported for the first time. The binding of p-sulfonylphenoxy moieties to the phthalocyanine structure favors excellent solubilities in water, as well as providing an inhibition effect on carbonic anhydrase (CA) I and II isoenzymes and paraoxonase (PON1) enzyme. According to biological activity results, both complexes inhibited hCA I, hCA II, and PON1. Whereas 1 and 2 showed moderate hCA I and hCA II (off-target cytosolic isoforms) inhibitory activity (Ki values of 26.09 µM and 43.11 µM for hCA I and 30.95 µM and 33.19 µM for hCA II, respectively), they exhibited strong PON1 (associated with high-density lipoprotein [HDL]) inhibitory activity (Ki values of 0.37 µM and 0.27 µM, respectively). The inhibition kinetics were analyzed by Lineweaver–Burk double reciprocal plots. It revealed that 1 and 2 were noncompetitive inhibitors against PON1, hCA I, and hCA II. These complexes can be more advantageous than other synthetic CA and PON inhibitors due to their water solubility. Docking studies were carried out to examine the interactions between hCA I, hCA II, and PON1 inhibitors and metal complexes at a molecular level and to predict binding energies.