The role of demixing effect in analyte emission enhancement by easily ionized elements in d.c. plasma

Pavlović, Marija; Kuzmanović, M.; Pavelkic, Vesna M.; Marinković, M.

doi:10.1016/s0584-8547(00)00242-1

Cited by 15 publications

(12 citation statements)

References 16 publications

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“…The results qualitatively agree with the model of reducing the demixing effect in the arc plasma by introducing EIE [11]. Namely, radial demixing of the analyte in the plasma volume becomes partially reduced by the presence of EIE in the plasma, producing emission enhancement.…”

Section: Wwwcpp-journalorgsupporting

confidence: 85%

Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field

Stoiljković

Pavlovič

Savović

et al. 2007

Contrib. Plasma Phys.

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Key words DC arc plasma with aerosol supply, optical emission spectroscopy, plasma/magnetic field interaction. PACS 52.50.Dg Direct current (dc) arc plasma with continuous aerosol supply was coupled with an external oscillating magnetic field of a few tens of mT and a frequency of up to 1 kHz. Such configuration was used to alter the plasma-related radiative properties. The magnetic field was oriented perpendicularly to the electric field in the plasma and forced the arc column to oscillate as a whole with respect to the surrounding atmosphere. The magnitude of the applied magnetic field controls the amplitude of the oscillatory motion. Several parameters that can contribute to the radiative properties of the plasma were investigated (arc current, composition of aerosol introduced into the plasma, amplitude and frequency of the magnetic field applied). Spectral emission from different zones of the plasma column was measured by optical emission spectroscopy (OES). In comparison to steady-state plasma, the applied magnetic field induces an intensity enhancement of emission of the most analytes considered. The intensity enhancement is strongly affected by the amplitude and frequency of plasma column oscillations, i.e. by plasma column velocity. Also, intensity enhancement depends on the plasma zone observed.

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Section: Wwwcpp-journalorgsupporting

confidence: 85%

Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field

Stoiljković

Pavlovič

Savović

et al. 2007

Contrib. Plasma Phys.

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“…Because of substantial lowering of the radial electric field, typical arc discharge may change to a diffuse discharge. For every arc current there is a critical concentration of K that produces such a change in the arc operation mode [12].…”

Section: Resultsmentioning

confidence: 99%

“…In general, demixing due to mole fraction gradients is large only when chemical elements present in the plasma have different ionization energies. In that case, demixing due to mole fraction gradients leads to an increase in the mass fraction of the chemical element with the higher ionization energy in the high-temperature region [12,37,38]. Since argon and nitrogen ionize at similar temperatures, demixing due to mole fraction gradients is expected to be small.…”

Section: Plasma Chem Plasma Processmentioning

confidence: 99%

“…In the studied plasma source, due to demixing [12], the emission maxima of the nebulized elements are located at different distances from the axis, which mainly depend on the ionization potential of the corresponding element. In the all argon plasma, for the elements under study, the peaks of line emission are distributed over a rather wide region (from 1 to 4 mm).…”

Section: The Effect Of Nitrogen On the Analytical Performance Of The mentioning

confidence: 99%

“…Impact of the introduction of EIE (usually in the form of KCl) to the argon arc plasma depends on the concentration of added EIE. In low concentrations, the effect of EIE is reflected primarily in the reduction of the radial electric field [12] while the temperature remains essentially unchanged. The reduction of the radial electric field allows for better penetration of the analyte into the hotter plasma zones, which results in the enhancement of the analyte spectral emission.…”

Section: Introductionmentioning

confidence: 99%

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Properties of Argon–Nitrogen Atmospheric Pressure DC Arc Plasma

Ranković

Kuzmanović

Pavlović

et al. 2015

Plasma Chem Plasma Process

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The effect of nitrogen addition (1-20 %) on atmospheric argon DC arc plasma parameters was investigated. Nitrogen was added to three initial plasma gas compositions: pure argon gas, argon gas with water aerosol, and argon gas with water aerosol containing 0.5 % KCl. Admixtures of nitrogen from 1 up to 10 % (in the case of Ar-N 2 -water aerosol plasma) or up to 5 % (in the presence of 0.5 % KCl) produced a more contracted discharge, with larger gradients of electron number density and temperature, as compared to plasma without molecular gas addition. The opposite effect was observed in gas mixtures with 20 % of nitrogen. In that case, the arc core was expanded, and the radial profile of electron density and temperature became flatter as compared to the case of pure argon plasma. The changes in the radial structure of the discharge could be explained by increased thermal conductivity of mixed gas plasma and the presence of molecular ions. Increasing nitrogen content brings plasma closer to thermal equilibrium. To evaluate the effect of nitrogen upon analytic performance of the arc source, limits of detection (LODs) were measured for Zn, Cu, Li, and Rb. In plasma without KCl, the addition of nitrogen resulted in lowering of LODs for Cu, Li and Rb, while the opposite was observed for Zn. In the presence of KCl the addition of nitrogen had little or no effect on LODs for Cu, Li and Rb, while detection limits for Zn were increased.

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Study of aerosol sample interaction with dc plasma in the presence of oscillating magnetic field

Stoiljković¹,

Pavlović²,

Savović³

et al. 2005

Spectrochimica Acta Part B: Atomic Spectroscopy

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The role of demixing effect in analyte emission enhancement by easily ionized elements in d.c. plasma

Cited by 15 publications

References 16 publications

Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field

Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field

Properties of Argon–Nitrogen Atmospheric Pressure DC Arc Plasma

Study of aerosol sample interaction with dc plasma in the presence of oscillating magnetic field

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