Analytical carbon furnace atomic emission: Temperature measurements and excitation mechanism

Alder, John F.; Samuel, A.J.; Snook, Richard D.

doi:10.1016/0584-8547(76)80051-1

Cited by 10 publications

(8 citation statements)

References 5 publications

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“…The emission signal from the excited-state population could be detected over a longer period of time than the absorption signal from the ground-state population. Observations similar to these were reported by Alder et al (9) when iron was atomized in a HGA-70 furnace. It can also be seen from Figures 2-5 that ionization of Li, K, Rb, and Cs in the graphite furnace at 2300 °C is not significant from the viewpoint of atomic absorption, but ionization interference should be taken into consideration for K, Rb, and Cs when atomic emission signals are measured.…”

supporting

confidence: 88%

“…The question of whether or not ionization interference even occurs with these devices has not been adequately resolved (2-6). Recent data (7)(8)(9)(10)(11) suggest that local thermal equilibrium (LTE) is achieved in tube-type furnaces under the conditions of interrupted purge gas flow. Although the maximun temperatures experienced by atomic vapor in electrothermal atomizers are lower than those attained in a nitrous oxide-acetylene flame, sufficient thermal energy is available through collisional excitation processes to populate upper electronic energy levels lying as much as 5.28 eV above the ground state (2).…”

mentioning

confidence: 99%

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Analyte ionization in graphite furnace atomic absorption spectrometry

Sturgeon¹,

Berman²

1981

Anal. Chem.

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supporting

confidence: 88%

mentioning

confidence: 99%

Analyte ionization in graphite furnace atomic absorption spectrometry

Sturgeon¹,

Berman²

1981

Anal. Chem.

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“…During the atomization step at 2750 °C some emission lines, not resolved by the polychromator, are observed: these lines are attributed to excited vanadium atoms (305.6,306.0,306.6 and 318.3,318.4,318.5 nm) and to excited nickel atoms (lines from 335 to 350 nm) (11,12)•, as reported above, the system does not distinguish excited from ground state atoms, but simply detects the sum of emission and absorption. Therefore it can be deduced that the excited atoms contribute significantly to the overall behavior of the vapor phase, in agreement with previous observations (13,14).…”

Section: Resultssupporting

confidence: 91%

Simultaneous molecular and atomic spectrometry with electrothermal atomization and diode array detection

Tittarelli¹,

Lancia²,

Zerlia³

1985

Anal. Chem.

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Sir: Some papers dealing with the ultraviolet and visible study of molecular vapors produced by electrothermal atomizers were recently published (1-5). Various instruments were proposed depending on the aim of the work, from conventional flameless atomic absorption spectrometers (1-4) to dedicated equipment (5).Recently also the infrared range has been investigated, coupling an FT-IR spectrometer with a heated graphite atomizer, thus introducing further analytical applications of this device (6). At the same time new techniques have been developed for simultaneous multielement determination by graphite furnace atomic absorption (GFAA) or emission spectrometry (7)(8)(9).Considering these different applications, it seems advisable to explore the capability and behavior of electrothermal atomizers in acquiring, with the same equipment, molecular and/or atomic spectra for qualitative and quantitative analysis. This work reports some results obtained by a single instrument, made up of a graphite furnace and a diode array detector, in the ultraviolet investigation of vaporization phenomena of organic and organometallic compounds previously studied (2,4, 6).EXPERIMENTAL SECTION Apparatus. The equipment consists of a graphite furnace atomizer, Perkin-Elmer HGA-76 B, and Jasco KS-1Q0 M multispectrometer modified to meet the requirements of this study.The atomizer is equipped with an AS-1 autosampler, while solids are sampled as previously described ( 6). The spectrometer includes a deuterium source, polychromator, data processor, and recorder. Deuterium lamp, atomizer, and polychromator are mounted on an optical rail. The diode array of the polychromator (512 elements 25 pm wide) is a Reticon 512 S. The wavelength range (190-355 nm) is focused on the detector diodes by a concave holographic grating (500 lines/mm) blazed at 230 nm. A baffle inserted in front of the entrance slit of the polychromator reduces the detection of light emitted by the graphite furnace tube walls.The calculated resolution of the polychromator is about 0.3 nm/diode and the stray light is evaluated below 0.3%.The data processor can acquire up to 16 spectra with collection times varying from 0.05 s to 1 s and interval times from 0.05 s to 25 s. The spectra are transferred by RS-232 C interface to a Perkin-Elmer 7500 professional computer for absorbance calculation, data storage, and representation.Reagents. Crude oils, pigments, and polymers are examined in this work. The oils are diluted 1 to 10 with pure grade toluene. Pigment Blue 15 (copper phthalocyanine), Pigment Yellow 1 (monoazo derivative of 2-nitro-p-toluidine and acetoacetanilide), and Pigment Red 48:4 (Mn salt of monoazo derivative of 6amino-4-chloro-3-methylbenzenesulfonic acid and 3-hydroxy-2-

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“…It is assumed that local thermal equilibrium is achieved in the furnace and that the temperature of the analyte vapor has equilibrated to that of the wall at each point in time. Substantial experimental data support this view (15)(16)(17)(18). It is further assumed that ionization is thermal in origin (no chemi-ionization) and that the analyte is only singly ionized with no significant molecular ionization.…”

Section: Theorymentioning

confidence: 99%

“…The relatively low temperature in the graphite furnace would not promote second ionization. Recent evidence suggests that ionization of metal vapors occurs predominantly by thermal processes (14,15,17).…”

Section: Theorymentioning

confidence: 99%

Determination of the efficiency of the graphite furnace for atomic absorption spectrometry

Sturgeon¹,

Berman²

1983

Anal. Chem.

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Atomic Numberif longer time was used, the predicted values would degrade, for this comparison, by the square root of the ratio of times.In any case, it should be obvious that the experimental results show that the predictions were not overly optimistic. This work will be extended to include the use of monochromatic radiation. The reduction in incident intensity will be weighed against the tunability and lower background. ACKNOWLEDGMENT Special thanks are given to Alan Webb for assistance with the experimental configuration and to the staff at SSRL for their enthusiastic cooperation.

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Analytical carbon furnace atomic emission: Temperature measurements and excitation mechanism

Cited by 10 publications

References 5 publications

Analyte ionization in graphite furnace atomic absorption spectrometry

Analyte ionization in graphite furnace atomic absorption spectrometry

Simultaneous molecular and atomic spectrometry with electrothermal atomization and diode array detection

Determination of the efficiency of the graphite furnace for atomic absorption spectrometry

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