摘要:

A brief overview of analytical chemistry research in Australia is presented and reference is made to the work of several research groups. Topics covered include the development of a longitudinally modulated cryogenic system for comprehensive gas chromatography, mixed-mode capillary electrochromatography for manipulation of separation selectivity of inorganic ions, new developments in chemical metrology, discontinuous flow analysis and its applications, the design and applications of an orthogonal acceleration time-of-flight mass spectrometer, and the use of chemiluminescence in a range of analytical techniques.

ISSN:0003-2719    

DOI:10.1080/00032719908543016

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An amperometric glucose biosensor was constructed based on a glassy carbon electrode modified with a Cobalt(II)hexacyanoferrate film which catalyzes electroreduction of hydrogen peroxide. Gelatin was used as immobilization matrix. Interference could be effectively eliminated by the combination of low detection potential with a Nafion coating. A low applied potential can avoid oxidation of interferences such as ascorbic acid, uric acid,p-acetyl-aminophenol, etc.. Nafion coating prevents interferences from access to the electrode surface by electrostatic repulsion. A wide linear range of detection was obtained. Analytical performance parameters are given and kinetic analysis discussed.

ISSN:0003-2719    

DOI:10.1080/00032719908543017

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An adsorptive stripping square-wave voltammetric method for quantitative determination of creatine is developed. The basic redox properties of creatine are investigated by means of square-wave and cyclic staircase voltammetry. Creatine undergoes an irreversible reduction in neutral and acidic medium at a hanging mercury drop electrode. The square-wave voltammetric response of creatine depends on the parameters of the SW excitation signal as well as on the concentration and type of the supporting electrolyte, the accumulation time and the potential and pH of the medium. The optimal experimental conditions for quantitative determination of creatine are as follows: supporting electrolyte 0.1 mol/L KNO3buffered with 0.1 mol/L acetate buffer to pH = 4 and accumulation potential -1.2 V. The optimal SW parameters found are: frequencyf= 120 Hz, amplitudeEsw= 30 mV, and scan increment dE= 4 mV. A detection limit of 6.6 x 10−8mol/L creatine was obtained after 30 s preconcentration period at accumulation potential -1.2 V. The correlation coefficients of the calibration curves at concentration levels of 10−7to 10−5mol/L creatine are greater than 0.99. The results of recovery tests range from 92.18% to 102.51%.

ISSN:0003-2719    

DOI:10.1080/00032719908543018

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The modified glassy carbon electrodes prepared by simultaneously covering with [Os(bpy)2(PVP)10Cl]+redox polymer and Nafion film exhibited excellent electrocatalytic activity for the oxidation of dopamine (DA). Dual linear regions between 1.0x10−8-1.8x10−5M and 1.8x10−5-4.0x10−4M with correlation coefficients of 0.998 and 0.995, respectively, were obtained for log-log plots of catalytic current versus DA concentration. The detection limit for DA determination was ca. 5 nM with 3σ. The dual-film modified electrodes eliminated efficiently the interference from AA presence in a 1000-fold concentration ratio and showed excellent reproducibility for the determination of DA. The modified electrodes have been used to determine DA concentration with both cyclic voltammetric and chronoamperometric techniques. Electrocatalytic kinetics have been studied using a rotating disk electrode. Both the addition of Nafion film and an increase in DA concentration resulted in a decrease in the electrocatalytic rate constant. An apparent Michaelis-Menten constant of 1.3 mM and maximum catalytic current of 88μA were evaluated from the chronoamperometric measurements.

ISSN:0003-2719    

DOI:10.1080/00032719908543019

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Albendazole is determined by differential-pulse adsorptive cathodic stripping voltammetry at a hanging mercury drop electrode using the reduction peak of its copper(II) complex at −0.28V at an accumulation potential 0.0V vs. Ag/AgCl electrode. The optimum conditions of pH, accumulation potential and accumulation time were studied. The calibration graph for the determination of albendazole was linear in the range 3.0X10−8- 9X10−7M with a relative standard deviation of 2.8%. The detection limit was 1.0X10−8M after 180s accumulation at 0.0V. The effect of common excipients and metal ions on the peak height of albendazole was studied. The presence of Cu2+ions forms a stable complex with albendazole which is strongly adsorbed at the mercury electrode surface. The method was applied to the determination of the drug in commercially available dosage forms.

ISSN:0003-2719    

DOI:10.1080/00032719908543020

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A flow injection analysis method for the determination of cefadroxil is proposed. The method is based on the hydrolysis of cefadroxil in sodium hydroxide solution followed by treatment with 1,4-phenylenediamine and Fe(III) in sulphuric acid solution to produce a violet color which has a maximum absorption at 600 nm. Variables such as acidity, reagent concentrations, flow rate of reagents and other FI parameters were optimized to produce the most sensitive and reproducible results. The calibration graph is linear between 80 - 320 mg/l. The detection limit is 40 mg/l with a relative standard deviation, RSD (n=6) of 1.8%. The proposed method, combining the advantages of speed and accuracy was applied to the determination of cefadroxil in pharmaceutical preparations. The results have been compared with those obtained using HPLC method (USP-procedure). Excellent agreement between the results of the proposed method and the HPLC method was observed.

ISSN:0003-2719    

DOI:10.1080/00032719908543021

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A spectrophotometric method of assay of chlorpheniramine in some of its dosage forms based on the principle of charge transfer complexation between chlorpheniramine (the n – donor) and chloranilic acid (the π - acceptor) is described.

ISSN:0003-2719    

DOI:10.1080/00032719908543022

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The relative lipophilicity of ten metallic complexes of 4-methoxyphenyl-4'-chlorobenzoylhydrazine with Cu2+, Co2+, Mn2+, Ni2+, Pd2+, Fe3+, Cr3+, La3+, Ce4+and UO22+with potentially anti-inflammatory properties have been determined by reversed-phase thin-layer chromatography using C18plates and water-methanol mixtures as eluents. The RFvalues of each compound increased linearly with increasing concentration of methanol in the eluent. Principal component analysis allowed a more rational and objective estimation and comparison of lipophilicity determined by RPTLC. Scatterplots of the scores onto a plane described by the first two components showed clustering of the complexes according to the nature of the central cation, obtaining in this way a "congeneric lipophilicity chart". Generally, the presence of cation increases the lipophilicity expressed as scores along the first principal component, practically in the same way. This means that the lipophilic behavior of metallic complexes depends firstly of the structure of ligand. However, the most lipophilic effect was observed in the case of Cu2+, Pd2+, La3+and Cr3+.

ISSN:0003-2719    

DOI:10.1080/00032719908543023

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

By designing a novel flow-through electrolytic cell, Br2, an unstable and toxic reagent, can be produced in-situ on the near region of a platinum electrode surface by constant current oxidizing KBr in H2SO4medium. At the same time, it was found that a strong CL signal was produced when the basic H2O2solution was injected into the electrolytic cell. Based on this observation, a simple, rapid and selective ECL method for the determination of H2O2was proposed. Factors affecting the determination of H2O2, including the chemical and flow-injection parameters as well as the design of flow-through electrolytic cell, were investigated, and the possible ECL reaction mechanism was also discussed. Under the optimum conditions, the ECL emission intensity was linear with H2O2concentration in the range of 1.0x10−6− 4.0x10−3mol/L and with 3.5x10−7mol/L detection limit.

ISSN:0003-2719    

DOI:10.1080/00032719908543024

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The present study is based on the interaction of diazotized 4-amino-6-chloro-1,3-benzene disulphonamide (DACBS) with 8-hydroxyquinolines in slightly alkaline medium and with dibenzazepines in strongly acidic medium to form red coloured products in the range of 500- 555 nm. Under optimum reaction condition, Beer's law is obeyed in the concentration range 0.5-25 μg/ml for 8-hydroxyquinolines and 1.0-25 μg/ml for dibenzazepines. The stoichiometry of the reaction was investigated and was found to be 1:1 for all the studied drugs. Interference due to other co-formulated drugs, common additives and excepients was studied. The proposed method was applied successfully for the determination of the cited drugs in their pharmaceutical preparations and results were comparable with that of the official, reported method.

ISSN:0003-2719    

DOI:10.1080/00032719908543025

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor