Talanta
Copper(III) solutions are found to give an instantaneous stable pink-coloured product with 0.2% aqueous p-anisidine in the presence of 0.03N acetic acid. The wavelength of maximum absorption is 533 nm and obeys Beer's law up to 0.89408 g copper(III). It is also recommended as a spot test for copper(III).
The speciation of iron and manganese compounds retained by membrane filtration of dam water samples was studied by use of electron spectroscopy for chemical analysis (ESCA). Samples were taken at various depths and times of year from North Pine Dam near Brisbane, Australia. Both surface and bulk properties of samples representative of the water column profile were investigated. ESCA results showed...
The optimum chromatographic separation conditions for Co(II), Ni(II), and Fe(III) chelates with 2-(2-thiazolylazo)-5-dimethylaminophenol (TAM) were investigated. The compositions of chelates were also determined by the HPLC method and thus the possible structure of chelates was given. A precolumn derivatization method was used, followed by separation on an octyl-bonded silica stationary phase with...
A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable for direct determination...
Oxidized glutathione (GSSG) can be determined after previous accumulation on the HMDE at E > -0.2 V (vs. the Ag/AgCl reference electrode). GSH is formed during the accumulation, possibly by a mercury-ion-assisted hydrolytic disproportionation of GSSG. In the subsequent cathodic scan GSH is released and catalyses the reduction of nickel ion, giving a peak located at -0.6 V. This enables the determination...
Electrothermal atomic absorption spectrometry (ETA-ASS) of gold with a molybdenum tube atomizer has been investigated. A sensitive ETA-AAS method was developed. The gold absorption signal became higher with the heating rate of the tube atomizer and as the ratio of hydrogen in the argon purge gas decreased. The optimal heating rate and the optimal gas flow rate were 5.5°C/msec and Ar 480 ml/min...
An ion-exchange method has been developed for the separation of palladium, platinum and rhodium from a solution that is highly acidic and contains a considerable amount of lead, aluminum, iron and cerium, obtained by leaching a used honeycomb type automotive catalytic converter. A column of Amberlite IRA-93 anion-exchange resin was found appropriate to recover platinum metals from the pregnant solution...
A method for the quantitative preconcentration of lead based on an existing batch process was developed for implementation in a flow system including a flame AAS detector. Lead can be quantitatively preconcentrated as pyrrolidinedithiocarbamate or dithizonate on an activated carbon minicolumn. The chelates are eluted in methyl isobutyl ketone and introduced directly into the nebuliser-burner. An...
A flow injection (FI) determination for chloride has been developed using the light reflectance of the precipitate formed by the reaction of chloride with silver(I) as the method of detection rather than turbidimetry, as in the previous FI method using this reaction. The dynamic range of the analysis is increased to 0-10 mM chloride with a 10 mM silver(I) reagent and to 0-50 mM chloride with a 50...
Alkali and alkaline earth metals were separated and quantified by Capillary Zone Electrophoresis using a previously developed method. CZE combined with indirect detection has received considerable attention over the last few years. Methods for the determination of inorganic and organic cations and anions have been reported although few of these include quantitative application to real samples. ...
Potentiometric titration was used to determine the logarithms of the stepwise equilibrium constants for the species formed between morpholine and formaldehyde in aqueous solution, ionic strength 0.5 and 2.5M (KCl) at 25°C. The instrumental and computational techniques developed for metal-ligand stability constant determination were applied. Formaldehyde is equivalent to the metal-ion and is represented...
A sensitive and relatively selective high performance liquid chromatographic method for the determination of Gentian Violet (GV) in human urine and chicken feed is described. The method is based on solid-phase extraction, with subsequent reversed-phase chromatographic separation on a cyano column and amperometric detection using a carbon fibre microelectrode flow cell operated at +1.3 V. The peak...
A continued investigation of the primary steps in diphenylamine (DPA) decomposition in nitrocellulose (NC) propellants is presented. The study is based on analytical data obtained by reversed-phase liquid chromatographic separation of the initial degradation products of DPA. Spectrophotometric detection, rather than the amperometric detection used in part I of this work (A. Bergens and R. Danielsson,...
An overview of the state-of-the-art in flow injection analysis (FIA) coupled to instruments capable of providing either multidetection and/or multi-information is reported. The versatility of FIA endows the hyphenated instruments with analytical capabilities which increase from simple sample introduction to more complex sample handling such as automatic dilution and calibration, solvent exchange,...
The consumption of diphenylamine (DPA) in two nitrocellulose (NC) based propellants subjected to a heat storage test at 85° has been studied. A previously developed method based on reversed-phase liquid chromatography with dual-amperometric detection was used to monitor the concentrations of DPA, 2-nitro-DPA and 4-nitro-DPA during the test. A numerical model based on first order rate equations was...
An electroanalytical method for determination of the anti-inflammatory agent aceclofenac at the ppb level using adsorptive stripping voltammetric techniques on conventional and surfactant chemically modified electrodes is developed. In this electroanalytical study a process of aceclofenac adsorption on carbon particles has been identified. In order to improve the aceclofenac determination, a chemical...
Re-evaluation of DPASV procedures for determining low levels of Sb (III) and Sb (V) in solution identified several problem areas, e.g. anomalous ASV behaviour, possible formation of an intermediate valency state during the analytical cycle, and chemical interactions in acidified test solutions containing both valency states. Specific determination of Sb (III) can be achieved using base solutions...
A highly sensitive galvanic cell oxygen sensor was successfully developed for determining parts per billion of oxygen in high purity gases such as nitrogen, argon, etc. The response of this improved sensor was proportional in the range of oxygen concentrations from 10.0 ppm to the detection limit. The response speed in this study was improved to within 90 sec for a 90% response. The detection limit...
A method for elucidating metal ion binding mechanisms with water-soluble polymers has been developed in which the polymer is treated as a collection of monomeric units. Data obtained from potentiometric titrations are analysed by the ESTA library of programs and apparent formation constants may be calculated. From this information, predictions may be made as to metal ion separation using complexation-ultrafiltration...
The kinetic behaviors of Cr(VI) and W(VI), which catalyze a common indicator reaction between H 2 O 2 and I - , were studied. A new concept, Rate Spectrum , is proposed. The two catalysts can be determined simultaneously by analyzing the rate spectra of their mixtures as the rate spectra of each catalyst are linearly independent. Principal Component Regression (PCR) was...