Polarography of metal-gallic complexes

The polarographic behavior of metal ions in perchlorate media containing gallic acid is described. Tungsten(VI) forms a complex with gallic acid which yields a single wave in these media, useful in the polarographic determination of tungsten. Evidence for complexation of chromium(III), copper(II), iron(III), molybdenum(VI), uranium(VI), vanadium(V), tungsten(VI), praseodymium(III), samarium(III), neodymium(III) and gadolinium(III) is obtained and the behavior of these metal ions is summarized.     

Application of differential pulse polarography for trace determination of polycytidylic acid in absence and presence of some metal ions

Summary A differential pulse polarographic method has been applied to the determination of trace concentrations of polycytidylic acid (Poly-C) in absence and presence of metal ions. The applicability of differential pulse polarography for the trace determination of the investigated biological compound was examined with regard to the dependence of differential pulse current on various parameters such as pH, pulse amplitude, scan rate and drop time. The selectivity of this technique for the determination of binary and a ternary mixtures of poly-C and some metal ions has been also reported. Limits of detection and quantitation have been calculated for the differential pulse polarographic determination of the poly-C and various metal ions. The validity of this method is supported by the constancy of the i_p/C values and a statistical analysis is included on calibration curve parameters and observed concentration.     

痕量苯酚的单扫描极谱法测定

研究了碱性介质中苯酚与对氨基苯磺酸重氮盐所形成偶氮化合物的极谱行为，并建立了痕量苯酚的极谱测定方法。方法用于污水中微量苯酚的测定，结果令人满意。     

Polarographic determination of 9,10-anthraquinone and its 1,2- 1,4- and 1,8-dihydroxy derivatives in chloroform Application to the analysis of papers and black liquors

The polarographic behaviour of 9,10-anthraquinone (I) and some of its dihydroxy derivatives, such as alizarin (II), quinizarin (III) and chrisazin (IV) has been studied in the presence of proton donors of HA and HB⁺ type. After optimization of conditions for reversible reduction of the anthraquinones, various polarographic techniques were used for the determination of anthraquinones in chloroform. In the dc method, the relative standard deviation for the determination of 1mM concentrations was about 1.5%. In the ac method, the detection limit was 0.1 μg/ml and the relative standard deviation for determination at the 0.2 μg/ml level was 2%. The proposed methods are usable for the simultaneous determination of I and II, II and III, II and IV, and have been applied to the determination of 9,10-anthraquinone in papers and black liquors.     

The use of redox reactions in the analysis of dyes and dye intermediates: XVII. The influence of proton donors on direct current polarographic behavior of some water-insoluble azo pigments in acetonitrile

The influence of water and perchloric acid on the polarographic behavior of some water-insoluble azo pigments in acetonitrile has been investigated. The conditions were defined for the polarographic determination of the test substances in a mixed acetonitrile-water medium. The presence of strong acids prevents analytical use of these reactions.     

Indirect polarographic determination of arsenic

A method for determination of arsenic(V) in the range between 1 x 10(-7) and 1.2 x 10(-6)M has been developed. These levels are reached by means of the multiplication factor yielded by use of 12-molybdoarsenic acid and the great sensitivity of polarographic determination of the Mo(VI) in the heteropoly acid. The procedure has been successfully applied to determination of arsenic in copper alloys, after selective extraction of phosphorus.     

Simultaneous determination of N-unsubstituted and N-substituted nitroazoles and criteria for their identification-III Chromatographic separation and polarographic determination of halo-nitroimidazoles

Methods for identifying and determining halo-nitroimidazoles appearing together during synthetic processes, regardless of the preparation methods, are proposed. Polarographic determination can be used in all synthetic processes when halo-nitroimidazoles have been obtained by nitration of the halo-imidazoles. When the halo-nitroimidazoles have been obtained from 5(4)-halo-4(5)-nitroimidazoles by substitution of the imino hydrogen atom, and when only one N-substituted derivative has been obtained in a reaction mixture, simultaneous polarographic determination of both compounds is possible, but only when an alkaline medium is used as supporting electrolyte. In some cases, simultaneous polarographic determination of all three compounds present in a reaction mixture during N-substitution processes [one 5(4)-halo-4(5)-nitroimidazole and two N-substituted isomers] is also possible with alkaline supporting electrolyte. Explanations are given of the phenomena on which the simultaneous polarographic determination is based. When simultaneous polarographic determination cannot be used to determine the amount of each polarographically-active compound present in a reaction mixture, the compounds can be separated chromatographically and then determined individually by polarography.     

Electrochemical determination of diffusion coefficients of selected metals in dimethylsulfoxide

Diffusion coefficients of lead, zinc, thallium and gadolinium in dimethylsulfoxide have been measured electrochemically by means of the complete Koutecky equation. Instantaneous currents were measured on first drops from a D.M.E. and calculations were made by an iterative computer technique. Half-wave potentials, polarographic wave reversibility, and diffusion control data are reported.     

Differential pulse polarographic determination of molybdenum after separation by 8-hydroxyquinoline extraction into dichloromethane

A polarographic investigation of several metal 8-hydroxyquinolinates in dichloromethane medium following solvent extraction has been made. From the data obtained, a selective, specific and sensitive method for the determination of molybdenum at ng ml levels has been developed involving direct differential pulse polarographic measurement on the dichloromethane extract. In this work, EDTA is used as an effective masking agent to separate molybdenum from other metals. The proposed method has been applied to the determination of molybdenum in a variety of steels and NBS-SRM 1577 bovine liver with good accuracy and precision.     

赖氨酸与香草醛反应产物的极谱波特征及其分析应用

研究了赖氨酸与香草醛反应产物的极谱波特征并建立了赖氨酸的分析方法。在0.1mol/L磷酸盐缓冲溶液中赖氨酸与香草醛反应的产物于－1.16V产生灵敏的极谱波,赖氨酸浓度在5×10     

Sine-wave polarographic determination of zirconium or niobium in aqueous media

The sine-wave polarographic determination of zirconium in aqueous media was investigated using solutions which were 0.55 – 5.5·10^-3M in zirconyl chloride and 1 M in potassium chloride and had been adjusted to pH 2.0 with hydrochloric acid. It was possible to determine zirconium in the concentration range of 0.05 to 0.4 mg per ml. The sine-wave polarographic behavior of zirconium in aqueous solutions in the pH range 2–3 is discussed. The sine-wave polarographic determination of niobium in aqueous media was investigated using concentrated sulfuric acid containing 5 to 0.1 mg of niobium per ml in a supporting electrolyte of citric acid; the determination of niobium was possible down to 0.1 mg of niobium per ml of concentrated sulfuric acid although the D.C. polarographic method was impractical for the determination of less than 0.5 mg of niobium per ml.     

Indirect polarographic microdetermination of chlorine or bromine in organic compounds

A polarographic method for the microdetermination of chlorine or bromine in organic compounds is based on oxygen-flask combustion followed by an exchange reaction of chloride or bromide with excess of solid silver chromate, and polarographic determination of the chromate liberated. The method has been applied satisfactorily to a wide range of chlorine or bromine organic compounds with a coefficient of variation not exceeding 1%.     

Polarography of arsenic

The polarographic behaviour of arsenic in various media is reviewed with particular emphasis on the mechanisms of the electrode reactions and on the use of polarographic methods for the determination of the element.     

Determination of carbonyl compounds via polarography of their semicarbazone derivatives

The polarographic behaviour of a range of aldehyde and ketone semi-carbazones has been studied and a method for the determination of carbonyl compounds developed. The carbonyl compound is added to an acetate buffer containing 0.1 M semicarbazide hydrochloride and 50% ethanol and the polarographic reduction wave of the semicarbazone derivative measured. The similar values of the diffusion current constant I for all compounds studied indicate the applicability of this method to functional group analysis.     

High precision comparative polarography

A new cell assembly for use with the differential cathode ray polarograph is described togother with full practical details of its use in comparative polaragraphy. The difficulties of manipulating the cells and dropping mercury electrodes have been greatly reduced. Results obtained show that the coefficient of variation of a polarographic determination can be as low as 0.04%. Some general aspects of the technique are discussed.     

Quantitative determination of narwedine inUngernia victoris andU. Severtzovii

Summary A polarographic method for the quantitative determination of narwedine inUngernia victoris and a chromatopolarographic method for its determination inU. severtzovii have been proposed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 610–612, September–October, 1975.     

Estimation of surfactant activity of polluted seawater by kalousek commutator technique

The polarographic method of discontinuously changing potential, known as the Kalousek commutator technique, was applied to the estimation of surfactant activity of seawater samples from polluted area of a harbour. Adsorption isotherms of different detergents, lecithin and lauric acid at the HMDE have been used as calibration curves. The method is recommended for direct and rapid determination of the degree of seawater pollution by organic surface active substances.     

m-Nitrophenylarsonic acid as a polarographic reagent for titanium

A sensitive polarographic method for titanium, based on its selective and quantitative precipitation with polarographically reducible m-mtrophenylarsonic acid is described, factors affecting the quantitative precipitation — pH, concentration, of titanium and reagent, nature and concentration of anions, and digestion — have been studied.After precipitation of the titanium under controlled conditions, the precipitate is dissolved and the polarographic diffusion current of the organic reagent is related, by a calibration, to the original titanium concentration.The method has been applied successfully to the determination of titanium in complex high temperature alloys, after the removal of iron by a mercury cathode electrolysis.     

Indirect neutron absorptiometry

A preliminary account is given of the use of the neutron absorption of suitable elements (such as gadolinium) for the determination of non-absorbing elements (such as fluorine) by measuring the absorption of a dissolved precipitate (in the case quoted, gadolinium fluoride). This indirect determination by neutron absorption gives reproducible results rapidly and non-destructibly. The applications of the method are being studied.     

Study on Polarographic Absorption Wave of Soluble Porphyrin Copper Complex

The porphyrins is a kind of sensitive color-producing reagent. However, its selectivity is low. If the porphyrin is used in polarographic analysis, the selectivity and sensitivity can be improved. Copper is one of the most important trace element in human and mammalian body. The polarographic method is a kind of important method in determination of metal ion [1]. In this paper, meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) is used as the soluble ligand. The polarographic absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin complex with copper ion has been studied.