Studies on the mechanism of atom formation in graphite furnace atomic absorption spectrometry

Sturgeon, Ralph E.; Chakrabarti, C. L.; Langford, Cooper H.

doi:10.1021/ac50006a041

Cited by 291 publications

(142 citation statements)

References 54 publications

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“…The latter seems to be not unreasonable and has sufficient support from various authors (4,5,8,9). The experimental activation energy, or the enthalpy of atomization, is defined here as the energy required to produce gaseous atoms (4,10). Several factors play an important role in determining the observed value of the enthalpy of atomization.…”

Section: Introductionmentioning

confidence: 57%

“…This method assumes that the release of atoins from the graphite surface is a desorption process (4,(12)(13)(14). Once a desorption process is assumed for a system, thermodynamic relationships can be applied to experimental data to yield the heat of desorption (1 5).…”

Section: Theorymentioning

confidence: 99%

“…Campbell and Ottaway (1) concluded from their study of 27 elements that the reduction of the metal oxide by carbon was thermodynamically feasible. Sturgeon et al (4,5 ) used a combined thermodynalnic and kinetic approach to obtain the activation energy of atom release from the onset of a plot of natural logarithm of the absorbance vs. the reciprocalof the absolute temperature. Frech et al (2) developed a thermodynamic model to study the distribution of solid, liquid, and gaseous analyte species in the graphite furnace as a function of temperature for 16 elements.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of atomization in a Massmann-type graphite furnace using the basic principles of thermodynamics

Cathum¹

1993

Can. J. Chem.

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A method has been developed to determine the enthalpy of atom formation in a graphite furnace without invoking the order of reaction. The method is based on the equation In (AT) = -AH'/RT + C , where A is [he peak-height absorbance, T is the absolute temperature. AH' is the enthalpy of atom formation which, for highly endothermic reactions, is considered to be equal to the activation energy, R and C are the universal gas constant and the constant of integration, respectively. The plot of In (AT) vs. 1 /T is similar to an Arrhenius-type plot and should yield the activation energy. Atomization mechanisms for eight elements, Cu, Co, Ga. Au, Ni, Fe, Ag, and Al, are proposed by correlating the experimental enthalpy with a very limited set of possible primary reactions. One significant result of this work is that the experimentally observed enthalpy of reaction correlates well with the activation energy, this means no excess energy other than the enthalpy of atomization is involved in the reaction.

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Section: Introductionmentioning

confidence: 57%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanism of atomization in a Massmann-type graphite furnace using the basic principles of thermodynamics

Cathum¹

1993

Can. J. Chem.

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“…The former is likely to occur because of the reported process of atomization for graphite-furnace atomic absorption spectrometry. 10 It was reported that the Ta strip atomizer for atomic absorption spectrometry was covered with Ta oxide under an oxidizing atmosphere." Thus, FeO is slowly dessociated at higher temperatures of the Ta sample cup, leading to a broader peak.…”

Section: Resultsmentioning

confidence: 99%

Excitation Characteristics and Matrix Effect in a Helium Radiofrequency Atomization and Excitation Source for Atomic Emission Spectrometry

et al. 1997

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“…Thermal decomposition of the carbide 24 or vaporization of the free metal 25 has been proposed as atomization mechanisms for chromium in GF AAS. However, these proposed mechanisms do not explain the behavior observed in the present work.…”

Section: Heating Program Optimization For Cr(vi) Speciationmentioning

confidence: 99%

In vitro Cr(VI) speciation in synthetic saliva after releasing from orthodontic brackets using silica-aptes separation and GF AAS determination

et al. 2016

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A method for Cr(VI) speciation in synthetic saliva after releasing from orthodontic brackets, using silica nanoparticles organofunctionalized with (3-aminopropyl)triethoxysilane (APTES) for Cr(III)/Cr(VI) separation and GF AAS determination is proposed. Under the optimized conditions, Cr(VI) speciation was performed using 150 mg of silica organofunctionalized with 2.0% (v v -1 ) of APTES at pH 8. It was observed different sensitivity when calibrations of GF AAS were performed using Cr(III) or Cr(VI) as standard solutions. Consequently, calibrations using stoichiometric mixtures (Cr(III) + Cr(VI)) were used for total Cr determination and calibration using Cr(VI) was used only for the determination of this specie. The reliability of the proposed silica-APTES separation procedure and GF AAS determination was checked by addition of both species in synthetic saliva. Recoveries ranging from 97 to 110% were obtained. The repeatability, based on the relative standard deviation (RSD) inter days was less than 6%. A corrosion test was carried out on 20 orthodontic brackets from two different models, after immersion in synthetic saliva (pH=6.0) at 37 °C with agitation (125 rpm) for 24 h. It was observed that about 40% of the total chromium released from the analyzed orthodontic brackets was Cr(VI).

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Studies on the mechanism of atom formation in graphite furnace atomic absorption spectrometry

Cited by 291 publications

References 54 publications

Mechanism of atomization in a Massmann-type graphite furnace using the basic principles of thermodynamics

Mechanism of atomization in a Massmann-type graphite furnace using the basic principles of thermodynamics

Excitation Characteristics and Matrix Effect in a Helium Radiofrequency Atomization and Excitation Source for Atomic Emission Spectrometry

In vitro Cr(VI) speciation in synthetic saliva after releasing from orthodontic brackets using silica-aptes separation and GF AAS determination

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