Effect of doping gases on microwave-induced emissive spectrometric detectors for gas chromatography

Serravallo, F. A.; Risby, Terence H.

doi:10.1021/ac60363a037

Cited by 30 publications

(11 citation statements)

References 53 publications

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“…The chromatograms obtained from serum samples (Figure 2 those of the standards. The contrast of these chromatograms with those we obtained earlier (15) with electron capture detectors is remarkable. While not strictly comparable because of differences in sample and treatment in the two methods, the results show striking differences.…”

Section: Resultscontrasting

confidence: 80%

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Determination of chromium in human blood serum by gas chromatography with a microwave excited emission detector

Black¹,

Sievers²

1976

Anal. Chem.

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Section: Resultscontrasting

confidence: 80%

“…The detection with MED is a function only of the specific metal atom of interest. Papers by Talmi and Andren (13), Kawaguchi et al (14), Serravallo and Risby (15), and Dagnall et al (16), have presented the use of a GC coupled MED for determining volatile metal chelates. The earlier studies were aimed at detector development and evaluation.…”

mentioning

confidence: 99%

Determination of chromium in human blood serum by gas chromatography with a microwave excited emission detector

Black¹,

Sievers²

1976

Anal. Chem.

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“…Plusieurs sation et les perf0I-mances analytiques de Ce dCtecauteurs ont Ctudii des dktecteurs similaires en teur en chromatographie en phase gazeuse sont utilisant des plasmas d'argon B diverses pressions rapportkes pour quatre elements en termes de ou d7hClium sous pression r~duite (2)(3)(4)(5) …”

Section: Introductionunclassified

Développement d'un détecteur à plasma micro-onde pour chromatographie en phase gazeuse

Chevrier¹,

Hanai²,

Tran³

et al. 1982

Can. J. Chem.

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The development of an atomic emission detector for gas chromatography is described. An atmospheric pressure microwave helium plasma generated with an original device called Surfatron was used as an atomization and excitation source. The characteristics of operation are defined and the analytical performances for carbon, chlorine, bromine, and iodine analyses are measured. Detection limits are in the order of pg/s and the dynamic range of the detector covers three orders of magnitude.

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“…The experimental results from an earlier study (5,21) are presented in Table V where they are compared to the calculated values of the same excited states based on the use of Equations 20 and 21. It should be readily apparent from consideration of Table V that the kinetic model, Reactions 1-4, accounts for the steady-state concentrations of excited atoms that are observed in electrical discharge.…”

Section: Resultsmentioning

confidence: 99%

“…ey. A consequence of this rather familiar dependence has been to identify this slope ß with (kT)-1, where k is Boltzmann's constant, and T is the excitation temperature (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). While it may be useful to characterize the excited state population densities of electrical discharges in this way, the attendant implication that the species present are in thermal equilibrium can be misleading.…”

mentioning

confidence: 99%

Steady-state kinetic treatment of the emission from reduced pressure microwave induced discharges in helium

Lampe¹,

Risby²,

Serravallo³

1977

Anal. Chem.

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A steady-state kinetic treatment of the number density of excited atoms in a helium dlscharge has shown these populations to be consistent wlth electron impact excitation. This study was initiated since it has been well establlshed that the electrons are the activating species In discharges. The calculated number densitles of exclted atoms were obtained by conslderation of the processes which cause excltatlon and deactivation. The processes whlch produce the population of a particular state are the followlng: electron Impact and radlative cascading from higher levels. The processes which reduce the population of a particular state are radiative and nonradiative deactivation. The results of this klnetlc treatment compare remarkably well wlth experlmental number densities obtained from emission studies.In a number of recent studies of light emission from electrical discharges, it has been reported that the population densities n, of the emitting states depend exponentially on the energy level of the state, i.e., n, CE e-PtJ where 6 is the slope of a plot of In n, us. e, . A consequence of this rather familiar dependence has been to identify this slope p with (kT)-', where k is Boltzmann's constant, and T is the excitation temperature (1-11). While it may be useful to characterize the excited state population densities of electrical discharges in this way, the attendant implication that the species present are in thermal equilibrium can be misleading.The process of excitation in electrical discharges is definitely not the result of collisions between particles in thermal equilibrium. Rather, excitation in such systems is brought about principally by the impact of energetic electrons on the gas atoms or molecules (12). The population densities of atoms in the various electronic states are then determined by a dynamic balance between formation via electron impact and decay via emission of radiation and nonradiative decay processes. In this paper, we treat this balance for reduced pressure microwave-induced discharges in helium by the method of steady-state kinetics. (4)in which the subscript i denotes optically accessible states of lower energy than j and the subscript k denotes optically accessible states of higher energy than j, kj is the rate constant (cm3/s) for excitation of the j t h state, A;i and Ak, are transition probabilities (s-l) for the emission processes j -i and k -j, respectively, and kA is the rate constant (cm3/s) for associative ionization. At the pressure of interest, it is easily shown that an emitting state will decay by Reaction 3 or 4 before it reaches a wall.On the basis of this mechanistic scheme, the change in number density of the j t h state with respect to time is:where ne is the density (~m -~) of electrons and n is the density (cm-3) of ground state helium atoms. The rate of population of the j t h state by radiative decay from higher states, Le., Reaction 3, is most probably only a few percent (23) of the rate of electron-impact excitation, Reaction 1. Therefore, as a reasonable appro...

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Effect of doping gases on microwave-induced emissive spectrometric detectors for gas chromatography

Cited by 30 publications

References 53 publications

Determination of chromium in human blood serum by gas chromatography with a microwave excited emission detector

Determination of chromium in human blood serum by gas chromatography with a microwave excited emission detector

Développement d'un détecteur à plasma micro-onde pour chromatographie en phase gazeuse

Steady-state kinetic treatment of the emission from reduced pressure microwave induced discharges in helium

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