Determination of mixtures of copper(II) and manganese(II) by electron spin resonance

Guilbault, George G.; Meisel, T.

doi:10.1021/ac60277a034

Cited by 23 publications

(13 citation statements)

References 2 publications

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“…Instrument. The ESR instrument and cell, filled with resin sample, are tuned according t o standard procedures (2,5,7,9). After tuning, the instrument, is placed in the "operate" mode; the microwave power raised to the maximum obtainable with the sample in question (this depensds on the amount of water bound to the resin); the detector current brought to 300 p A by turning the iris screw; and the frequency error adjusted to zero.…”

Section: Reagents Stock Solutions (Lo-' M) Of Coc12 In Distilled Watermentioning

confidence: 99%

Parameters influencing the electron spin resonance signal intensity of metal ion complex-exchanged resins

Warren¹,

Fitzgerald²

1977

Anal. Chem.

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Evaluation of quantitative ESR spectra of first row transition metal ions bound to iorrexchange resins reveals characteristics of a sensitive, measurable ESR signal. The Tanabe-Sugano theory, which qualltatlvely predicts spin relaxation times, facilitates the selection of an lon/ligand comblnation for each d electron configuration. Sensitive combinations of metal ion/ligand/resin for ESR measurements are limited by solution variables and further restricted by additional factors Including nuclear splitting, magnetlc anisotropy and spln-spin interaction. A systematic variation of F e ( I I 1 ) and Co(I1) ligand combinations is reported.The electron spin resonance (ESR) signal intensity is extremely dependent on local paramagnetic ion matrix effects ( I ) . If the spin environment is controlled carefully, the resonance signal intensity is linear with spin concentration (2). We have become interested in quantitative measurements of transition metal complex ions exchanged from aqueous solution onto ion-exchange resins (3). The ESR signal is strengthened by transfer to a low-dielectric, solid state and this is advantageous for analytical purposes. Both solution conditions (pH, ligand, oxidation state of ion) and resin type (strong or weak acid exchanger, polymeric resin backbone) must be considered when selecting conditions to obtain an intense ESR signal for a particular ion. Relaxation time effects and nuclear spinspin splitting are controlled by the particular ion/ligand combination chosen and influence the ESR signal (I,$). Relaxation effects may be reflected by an excessively broadened signal. Nuclear spin-spin splitting gives rise to a multiplet signal, where the intensity of a given line is only a fraction of the total intensity. Nuclear spin-spin splitting also increases the minimum detectable number of spins. Effects which result from the use of a solid matrix include magnetic anisotropy (1, 4 ) which decreases signal intensity and alters peak shape and spin-spin interaction which can cause a decrease in signal intensity ( I , 4 ) .Guilbault and Meisel (5) in an early study of the effect of diverse substances on the ESR spectra of aqueous Mn2+ solutions found that the effects of anions such as C1-, F-, Br-, C2H302-, and SCN-(weak to medium field ligands) are independent of the concentration of Mn2+ and generally insignificant. On the other hand, strong field ligands such as citrate, oxalate, CN-, tartrate, EDTA, and ethylenediamine cause a decrease in the ESR signal when ligand concentrations are equal to or greater than l / m the concentration of Mn(I1).If these ligands are present in concentrations equal to or greater than the concentration of Mn(II), the resulting complexes exhibit no ESR signal.Therefore, the ligand field surrounding a paramagnetic transition metal ion can profoundly affect the ESR signal shape and intensity. Perturbation theory has been applied 'Present address, to the spin Hamiltonian ( 4 ) and detailed predictions are available on the relative energies of the spin-orbit coupling and the...

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Section: Reagents Stock Solutions (Lo-' M) Of Coc12 In Distilled Watermentioning

confidence: 99%

Parameters influencing the electron spin resonance signal intensity of metal ion complex-exchanged resins

Warren¹,

Fitzgerald²

1977

Anal. Chem.

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“…As pointed out by these authors (19) the fact that the Cu-En complex gives a stable quartet spectrum can be used to advantage in determining the concentration of this metal in the presence of other components in the solution because this spectrum is not sensitive to the presence of quite large concentrations of other additives (see Table I).…”

Section: Determinations Of Transition Metal Ions By Esrmentioning

confidence: 99%

“…The ESR response was proportional to the nickel content of the aqueous sample in the range of 6.5 to 325.8 micrograms per 10ml sample. The structure of the nickel complex which gives the ESR signal is (45): The first attempt to develop a method for directly determining the concentration of one transition metal ion in the presence of another dealt with man gañese (II) and copper(II) mixtures (19).…”

Section: Determinations Of Transition Metal Ions By Esrmentioning

confidence: 99%

“…The authors show a typical spectrum (Figure 1, ref. 19) but it is difficult to see how seriously the Mn(II) spectrum is overlapped. They report that Mn(II) could be determined directly from the spectrum of the mixture containing Cu(II) although the converse was not true: Cu(II) could not be determined directly in the presence of Mn(II) because of the overlap problem.…”

Section: Determinations Of Transition Metal Ions By Esrmentioning

confidence: 99%

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Electron spin resonance

Janzen¹

1972

Anal. Chem.

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“…It has also been used in laboratory study of multicomponent systems (Guilbault and Moyer 1970, Guilbault and Misel 1969, 1970. This paper describes a survey of the EPR spectra of typical marine samples.…”

Section: Introductionmentioning

confidence: 99%

Electron paramagnetic resonance spectroscopy: A suggested approach to trace metal analysis in marine environments

Burgess

Chasteen

Gaudette

1975

Geo

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ABSTRACT/Electron paramagnetic resonance (EPR) spectroscopy analysis of marine samples from different environments appears to differentiate between adsorbed and structural Mn (ll) and Fe (Ill) sites in the sediment. This suggests that EPR may provide a means of distinguishing different environmental influences on sediment. Acid extract solutions from sediment samples exhibit clearly defined EPR spectra due to Mn(ll), Ti(lll), Fe(lll), and VO(IV), which are amenable to qualitative and quantitative analysis at concentrations below one part per million. Spectra of several shellfish vary considerably, both between species, and within a species, depending on sampling localities. Resonances from Mn(ll), Mo(V), and Fe(lll) can be obtained. Mn(ll) is substituted for Ca(ll) in the calcite structure of some shells.The low detection limits, small sample size, required and identification of oxidation states by EPR complement other analytical techniques and may prove useful in marine systems.

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Determination of mixtures of copper(II) and manganese(II) by electron spin resonance

Cited by 23 publications

References 2 publications

Parameters influencing the electron spin resonance signal intensity of metal ion complex-exchanged resins

Parameters influencing the electron spin resonance signal intensity of metal ion complex-exchanged resins

Electron spin resonance

Electron paramagnetic resonance spectroscopy: A suggested approach to trace metal analysis in marine environments

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