Jerry L. Jones

Electrogravimetric trace analysis on a piezoelectric detector

A novel and rapid electroanalytical method for the determination of cadmium at micromolar concentrations is described. The method utilizes the piezoelectric effect to follow small mass changes which result from electrodeposition.

Determination of iron and nickel in water and brine by solvent extraction and atomic absorption spectroscopy

Abstract A rapid, reliable and sensitive atomic absorption method for the determination of traces of iron and nickel in concentrated brine and in water has been developed. A simple, single extraction procedure is effective for iron in water at concentrations of 0.4–200 p.p.b. and in 25% (w/w) sodium chloride solutions at concentrations between 0.8 p.p.b. and 200 p.p.b. A similar procedure has been developed for nickel concentrations in the range 2–200 p.p.b. in water and 4–200 p.p.b. in brine. Extraction for 15 min with MIBK from a system buffered at pH 7 yields optimum results. The complexing agents are 0.2% solutions of 8-hydroxyquinoline and dimethylglyoxime for iron and nickel, respectively.

Potential sweep chronoamperometry in dimethyl sulfoxide at the hanging mercury drop electrode

Abstract Electroanalytical studies in dimethyl sulfoxide have been extended to the hanging mercury drop electrode. Potential sweep chronoamperometry was utilized with potentiostatic control of the working electrode. Several ions have been examined for diffusion control in this system by means of the Randies-Sevcik equation. Halfwave potentials of selected depolarizers and polarization limits of several carrier electrolytes have been measured.

Electrochemical determination of diffusion coefficients of selected metals in dimethylsulfoxide

Abstract 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.

Determination of diffusion coefficients from instantaneous current measurements and the kloutecky equation

Abstract Disagreements between experimental polarographic currents and those predicted by the Koutecký equation often arise from failure to consider depolarizer concentration depletion and the influence of back pressure on the time-dependent flow rate of mercury from the dropping mercury electrode. The magnitudes of these effects have been made negligible by measuring maximum currents on first drops and by adjusting the capillary constants. With proper consideration of the assumptions implicit in the mathematical model and careful experimental measurements, the use of the Koutecký current-time relationship has yielded polarographic diffusion coefficients for lead(II), zinc(II), and thallium(I) which agree with tracer values within 2%. The use of all three terms in the equation is shown to be justified. A computer program which utilized the Bolzano bisection reduced tedious calculations.

POLAROGRAPHY IN n-BUTYL PHOSPHATE

Abstract Direct polarographic measurements in n-butyl phosphate have shown that solvents of very low dielectric constant can be utilized to gather quantitative analytical data. Solutions containing cadmium in the millimolar range in 0.10M lithium perchlorate have been analyzed.

Electrochemical determinations of diffusion coefficients of some polynuclear copper(II) and iron(iii)complexes

Abstract Electrochemical data obtained by simple techniques appear to provide a valid means of detecting polymerization of metal complexes in aqueous solutions. Diffusion coefficients have been determined for the dimeric and trimeric iron(III) tartrate complexes and for some tartrate, citrate, salicylate, and 5-sulfosalicylate complexes of copper(II) by means of chronopotentiometry and conventional d.c. polarography. Approximate particle diameters were calculated from measured diffusion coefficients by the Stokes-Einstein equation and these confirm the presence of polynuclear species reported by earlier investigators. Scale models of the complexes have diameters which agree closely with those obtained experimentally. Evidence for the existence of a trimeric copper(II) tartrate species at pH 9.1 is presented.

Investigation of n-butyl phosphate as a solvent for voltammetry

Abstract Controlled potential voltammetric investigations of several depolarizers and potentially useful carrier electrolytes have been carried out in n -butyl phosphate. Half-wave potentials have been measured and analytical calibration curves have been constructed. Most depolarizers gave well formed waves but adsorption behavior was present in some cases. The influence of water was very significant.

Precipitation from mixed solvents: A demonstration

By applying the method of mixed solvents to the precipitation of nickel dimethylglyoximate from an acetone-water mixture, one can illustrate not only the striking influence of solvent composition on the quality and handling characteristics of the product, but the stepwise nature of the process as well.