Spectrophotometric Determination of Ampicillin with Some Nitro Compounds

Abstract

A spectrophotometric procedure for the determination of ampicillin (Amp.) in pure solutions and in its pharmaceutical preparations has been developed. This new method offers advantages of simplicity, rapidity and stability in comparison with the official BP (1980) method. The proposed method is based on the formation of a colour condensation product through the reaction of ampicillin and nitrobenzene derivatives in an alkaline aqueous-acetone medium 40% (v/v). Beer's law is obeyed in the range 0.5–28 μg ml^?1. The colours were produced within 20 min. after heating at 60±5°C and stable for at least 6 h. The method is relatively accurate (recovery 100±2%) and precise (RSD 1.9%) and can be used successfully for the preparation of capsules, syrup and ampoules.     

Rapid Determination of Minocycline in Pharmaceutical Formulations and Human Urine/Serum Samples Based on the Minocycline-Europium-Sodium Dodecylbenzene Sulfonate Luminescence System

Abstract

A new luminescence method based on the minocycline (MNC)-europium (Eu³⁺)-sodium dodecylbenzene sulfonate (SDBS) system was developed for the determination of MNC. SDBS formed a ternary complex with MNC-Eu³⁺ and significantly enhanced the luminescence intensity of Eu³⁺. The enhanced luminescence intensity showed a good linear relationship with the concentration of MNC over the range of 4.0 × 10^?7 ～ 1.0 × 10^?5 mol L^?1 with a detection limit of 2.0 × 10^?8 mol L^?1. This method is rapid and sensitive, and has been successfully applied for the determination of MNC in capsules and human urine/serum samples. The luminescence mechanism is also studied.     

Preparation and Properties of a Micro Enzyme Sensor for Creatine

Abstract

A micro enzyme sensor using creatine amidinohydrolase (EC 3. 5. 3. 3) and sarcosine oxidase (EC 1. 5. 3. 1) was developed for measuring creatine. The sensor consisted of platinum and silver wires fixed in a glass tubing with epoxy resin adhesive, and creatine amidinohydrolase and sarcosine oxidase immobilized on their tip by cross-linking method. The calibration curve for measurement of creatine, the effects of pH, temperature, the amount of flavin adenine dinucleotide and compounds on the sensitivity, and the life-time of the sensor were examined. Under optimal conditions, the response of the sensor was linear in the concontration range of 10 μ M ～ 0.65 mM creatine.     

Spectrophotometric Method for the Rapid Determination of Microgram Amounts of Ethionamide

Abstract

Spectrophotometric Method for the Rapid Determination of Microgram Amounts of Ethionamide

A simple and sensitive method for the determination of microgram amounts of ethionamide is described. Ethionamide is converted to corresponding 2-ethyl-γ-pyridyl thiohydroxamic acid which gives a purple violet colour (Λmax 510 nm) with ferric chloride in acidic medium. This forms the basis for the quantitative determination of ethionamide in its pure form and in tablet form. The influence of substrates, commonly employed as excipients, is studied. An attempt has been made to determine ethionamide in the presence of other antitubercular drugs.     

Spectrofluorimetric Determination of Antimony

Abstract

A spectrofluorimetric procedure for the determination of micromolar concentrations of antimony(III) was devised based on its reduction of cerium(IV) to produce fluorescent cerium(III). The method was optimized and the reaction was fast enough in hydrochloric acid media without the need for iodide or osmium(VIII) as catalysts. Linear calibration graphs were obtained in the range 1-10 10^?6M. The standard deviation for determining 5 × 10^?6M antimony(III)(10 times) was 1.43 × 10^?7M and the relative error was -3.4 %. The method was applied to the determination of antimony(III) in its mixture with antimony(V), total antimony was later determined after reduction with mercury metal in deoxygenated solutions. The affect several reducing agents on the determination of antimony-was also examined.     

Flow Injection Spectrophotometric Determination of Dipyrone in Pharmaceutical Formulations Using Fe(III) as Reagent

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.     

The Crystal Structure of Bis[N-(2,6-diisopropylphenyl)imino] Acenaphthene and Studies of its Copper(I) and Copper(II) Complexes

The crystal structure of the rigid bidentate nitrogen ligand bis[N-(2,6-diisopropylphenyl)imino]acenaphtene (o, o'-iPr₂C₆H₃-BIAN) is described. Syntheses, electronic spectra and electrochemical properties of two copper complexes containing (o,o'-iPr₂C₆H₃-BIAN), namely, [CuCl(o,o'-iPr₂C₆H₃-BIAN)₂]Cl (1) and [Cu(o,o'-iPr₂C₆H₃-BIAN)₂](CIO₄)(AcOH)₂ (2), where AcOH=acetic acid, are reported. Although in both complexes two o,o'-iPr₂C₆H₃-BIAN ligands are coordinated, geometries about the copper atom are significantly different. While complex 2 displays a strongly "flattened" distortion towards square-planar geometry, in complex 1 square-pyramidal coordination with an almost perfect planar arrangement of two o,o'-iPr₂C₆H₃-BIAN ligands around the copper centre is suggested.     

离子色谱法检测马铃薯及其淀粉中氢氰酸

建立了马铃薯及其淀粉中氰化物离子色谱的检测方法。样品经超声、冷冻离心、通过在线过滤处理后直接用离子色谱进行检测。检出限为0.054 mg/L,氰化物的线性范围为0.136～2.72 mg/L;加标回收率为85%～93%;相对标准偏差(RSD)为1.2%,可以满足氰化物检测的要求。     

化妆品中2种限用呫吨染料的高效液相色谱检测

建立了化妆品种中2种限用呫吨染料酸性黄73和溶剂橙16的高效液相色谱/二极管阵列检测器检测方法。在ODS C18反相色谱柱上,流动相为0.1 mol/L乙酸铵-甲醇-乙腈(体积比为65:17.5:17.5)等度洗脱,检测波长为492 nm,柱温35℃,流速1.0 mL/min。以保留时间定性,外标法定量。在5～500μg/mL范围内,酸性黄73和溶剂橙16的质量浓度与各自相应的峰面积呈现良好的线性关系,仪器检出限均为0.5μg/mL。样品前处理方法采用甲醇作溶剂超声提取,酸性黄73和溶剂橙16的加标回收率分别在91.2%～106.2%和93.2%～101.5%范围内。