共查询到20条相似文献,搜索用时 15 毫秒
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《Journal of Coordination Chemistry》2012,65(2):113-124
The reactions of ciprofloxacin (CIP) and norfloxacin (NOR) with iron(II) and iron(III) perchlorate have been investigated. The optical spectra support the formation of four complexes for each oxidation state with 1 : 1, 1 : 2, 1 : 3 and 1 : 4 metal to ligand molar ratios. The electrical conductivity and magnetic susceptibility measurements show that the isolated complexes are high spin and the Fe(ClO 4 ) 2 and Fe(ClO 4 ) 3 complexes behave as 1 : 2 and 1 : 3 electrolytes, respectively. The IR spectra indicate that CIP and NOR bind to the iron ion as bidentate ligands through the carbonyl oxygen atom and one of the oxygen atoms of the carboxylate group. 相似文献
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《Analytical letters》2012,45(12):2323-2332
Abstract A simple spectrophotometric method for the trace determination of nitrite (NO? 2) is described. Nitrite is reacted with Salbutamal sulphate in acidic medium which gives a yellow colour in alkaline medium (?pH 7) and can be determined in the presence of several cations and anions. Beer's law is obeyed in the range of 1.8 to 27.6 ppm of nitrite with the molar absorptivity 1.8 × 103 1 × mole?1 × cm?1 at 4l0 nm. The proposed method can also be utilized for the determination of nitrate (NO? 3) after its reduction to nitrite. The method has been applied for the determination of various samples containing traces of nitrite. 相似文献
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《Analytical letters》2012,45(3):389-401
Abstract A simple, sensitive and alternative method for the spectrophotometric determination of iron(III) has been established. The procedure is based on the formation of iron-azide complexes in 60% (v/v) tetrahydrofuran/ water medium. The high sensitivity obtained in this method is due to the use of an interesting absorption band not previously reported in the literature. In the recommended conditions, absorbances for the ferric complexes are measured at 400 nm where the molar absorptivity is 1.52 × 104 1 mol?1 cm?1. The organic solvent used increases the sensitivity and the stability of the measurements. The precision is shown by the average deviation of about 0.3%. This system obeys Beer's law and is suitable for iron(III) determination in the concentration range from 0.6 to 3.2 mg 1?1 (ppm). The best experimental conditions were determined studying the different factors involved. The influence of various diverse ions was also studied. 相似文献
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反相离子对高效液相色谱法测定动物血清中的环丙沙星 总被引:4,自引:0,他引:4
研究了用反相离子对HPLC测定动物血清中的环丙沙星(CPFX)的方法。血药由二氯甲烷提取,采用ODS柱,甲醇-乙腈-磷酸二氢钾-四丁基氢氧化铵为流动相,吡哌酸作内标,检测波长275nm。方法适应于CPFX血药浓度测定和药代动力学研究,并首次测定了山羊血清中CPFX。 相似文献
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《Analytical letters》2012,45(12):2074-2084
A flow-based methodology for the spectrophotometric determination of ciprofloxacin and norfloxacin, based on the oxidation with N-bromosuccinimide in acidic medium, was developed. The proposed procedure was implemented in a multi-pumping flow system, which provided excellent mixing conditions due to the pulsed flow produced by solenoid micro-pumps actuation, resulting on a sensitive, simple, fast, and versatile analytical method. Linear calibration plots were obtained for ciprofloxacin and norfloxacin concentrations ranging from 5 to 70 mg L?1 with an R.S.D < 2.2% (n = 10). Detection limits (3σ) were 0.27 mg L?1 and 0.99 mg L?1 for norfloxacin and ciprofloxacin, respectively. 相似文献
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《Analytical letters》2012,45(4):691-707
ABSTRACT The complex equilibria of iron(III) with 2-hydroxy-3-pyridinol (HHP), and 2-mercapto-3-pyridinol (MHP) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaCIO4). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance pH-graphs. After considering all the different parameters a simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of (Fe -MHP) complex at pH 2.5 (λmax = 640 nm, ? = l×104 L mol?1 cm?). The interference of a large number of foreign ions was investigated. The method has been applied successfully for the determination of iron content in some multivitamins with mineral preparations and infant milk products. 相似文献
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《Analytical letters》2012,45(10):741-751
Abstract Procedures are described for the determination of serum iron and iron binding capacity using the chromogenic reagent 4-(2-pyridylazo) resorcinol (PAR). The high molar absorptivity of the iron (II) PAR complex makes possible an approximate two fold increase in sensitivity over previous methods. The described procedures have few interferences, and give linear results for samples containing 0 – 750 μg/dl of iron. 相似文献
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《Analytical letters》2012,45(12):2289-2304
Abstract A flow injection analysis system which employs a visible absorption detector is used for the determination of beryllium. Be(II) ions are detected by means of a complexation reaction between Be(II) and chrome azurol s as the chomogenic reagent. The reaction forms a stable 1:1 complex which appears dark red-violet. The optimum conditions for the determination are pH 4.15, 35% chrome azurol s, 3% buffer, 62% HCI and 1,3-phenylenediamine, flow rate of 1.0 mL/min, and wavelength at 570 nm. A concentration limit of 0.1 μg/mL (or 2 ng in 25 μ of a sample injected) of Be(II) can be detected, and the linear dynamic range extends to 100 μg/mL. Some interference limits are established in the presence of EDTA and thiosulfate which are used as masking agents. 相似文献
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《Analytical letters》2012,45(10):2353-2358
Abstract The determination of trace iodide by preconcentration using solvent sublation and subsequent spectrophotometric measurements is described using cetyltrimethylammonium bromide (CTMAB) as a collector. the optimum conditions and the influence of diverse ions1 along with the wavelength of maximum absorption, concentration range and statistics of the method are presented. the method is applied to the iodide content in sea-water and results are compared with the iodide-starch method. 相似文献
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《Analytical letters》2012,45(6):707-717
Abstract A method for the spectrophotometrio determination of copper(II), in the presence of iron(III) cations (excess), was stablished. The masking of iron is made with sodium fluoride salt in 50 % (v/v) water/acetone medium. In the recommended conditions, absorbances for cupric complexes are measured at 435 nm where molar absorptivity is 6.00 × 103 1 mol?1 cm?1. The stable ayetern obeys Beer's law and is suitable for the copper determination in concentration range from 2.0 to 9.0 mg 1?l. The iron(III) ion interference (until ca. 600 mg 1?l) can be completely suppressed. The influence of diverse ions and several others factore were studied. The results show that copper(II) can be accurately determined by azide apectrophotometric method, if the samples were suitablely treated by the recommended procedure. 相似文献
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煤矸石中微量镍的催化发色光度法测定 总被引:8,自引:0,他引:8
研究了在 HAc- Na Ac缓冲体系中痕量Ni( )催化 KCl O3氧化还原型若丹明 B( RRh B)的显色反应 ,反应受温度、时间影响 ,冷却及加入抗坏血酸可终止反应。基于此 ,建立了一种测定痕量Ni( )的新方法。结果表明在 p H 4 .5~ 6.0的 HAc- Na Ac缓冲溶液中具有高灵敏的显色反应 ,方法的检出限为 4 .3× 10 -11g/ m L,催化程度与 Ni( )量在 0~ 0 .0 60 mg/ L范围内符合比耳定律。本法结合萃取分离 ,成功地测定了煤矸石中的微量镍。 相似文献
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《Analytical letters》2012,45(8):1477-1486
Abstract A method for the spectrophotometric determination of bismuth is described. The method is based on using polyether polyurethane foam sorbent as a favourable matrix. Sorption of the bismuth iodide complex into the foam thin layer contributed into substantial improvement of the measured absorbance value of the coloured species. In this way quite satisfactory results were achieved, the average recovery amounts to 105.25%. 相似文献
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硝普钠显色测定药物样品中甲巯咪唑 总被引:1,自引:0,他引:1
在溶液中NaOH浓度为6.7×10-3mol/L及0℃(冰水浴)条件下,反应时间为30 min,硝普钠与甲巯咪唑生成化学计量比为1碱性条件下硝普钠与甲巯咪唑反应生成化学计量比为1∶1的绿色产物,其最大吸收波长为610 nm。甲巯咪唑在4.8~48 mg/L浓度范围内与吸光度呈良好线性关系,线性回归方程为A=-0.0617 0.01329C(mg/L),相关系数r=0.9991;检出限为0.47 mg/L;相对标准偏差RSD=0.2%。本法成功用于测定片剂药品中甲巯咪唑的含量,平均回收率大于97.2%。 相似文献
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《Analytical letters》2012,45(1-3):340-348
A flow injection spectrophotometric procedure with symmetric merging zones for dipyrone determination in pharmaceutical formulations is proposed. The determination is based on the formation of a blue complex (monitored at a wavelength of 642 nm) yield in the complexation reaction of dipyrone with Fe(III) in acid medium. Under optimum conditions, a calibration curve was obtained from 3.5 to 281 mg L?1 with a detection limit of 2.8 mg L?1 and the samples throughput was 80 h?1. The analytical results obtained for commercial formulation samples by applying the proposed method were in good agreement with labeled values and those obtained by a comparative procedure at a 95% confidence level. 相似文献