Behavior of thorium, zirconium, and vanadium as chemical modifiers in the determination of arsenic by electrothermal atomization atomic absorption spectrometry

Castro, M.A.; García-Olalla, C.; Robles, L. C.; Aller, A. J.

doi:10.1016/s0584-8547(01)00355-x

Cited by 20 publications

(20 citation statements)

References 23 publications

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“…A hydride generation (HG) technique combined with any of the above methods is very effective for the determination of trace amounts of As. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Of the spectrometric methods, GFAAS is most widely used because of its robustness, easy operation and maintenance, low price, and low running cost, although ICP-MS is more sensitive than GFAAS.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Chemical Species of Arsenic on Sensitivity in Graphite Furnace Atomic Absorption Spectrometry

et al. 2008

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The sensitivity of graphite furnace atomic absorption spectrometry (GFAAS) to arsenobetaine (AB) was 1.3-times higher than to inorganic As. In order to understand the mechanism underlying this observation, the atomization processes for both chemical species were investigated in terms of the enthalpy change (ΔH) during the atomization process in GFAAS. The enthalpy change of AB was slightly lower than that of inorganic As, which suggested that AB was atomized more efficiently than was inorganic As. Moreover, it was observed that some co-existing organic materials enhanced the analytical sensitivity of inorganic As. The sensitivity difference between inorganic As and AB depended upon the mechanisms of their atomization processes.

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Section: Introductionmentioning

confidence: 99%

Effect of the Chemical Species of Arsenic on Sensitivity in Graphite Furnace Atomic Absorption Spectrometry

et al. 2008

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“…For a comparison, we also included a different metal (Th, as nitrate), which has proved to show good results as a chemical modifier for other analytes. 43 The results derived from such situations (Fig. 2) are shown to be different from those found for the metal chlorides.…”

Section: Behavior Of the Chemical Modifiers On The Atomization Of Cadmentioning

confidence: 74%

“…Thus, a fast temperature program was used in this work because it provides faster analysis and it is much easier to use in practice than a conventional program. 42 Recently, we have found some advantages using chemical modifiers 43 other than palladium, which has been largely considered to be a universal modifier. Thorium was selected because it was proved to be advantageous for those analytes capable to form oxides prior to the atomization stage.…”

Section: Introductionmentioning

confidence: 99%

Nickel as a Chemical Modifier for Sensitivity Enhancement and Fast Atomization Processes in Electrothermal Atomic Absorption Spectrometric Determination of Cadmium in Biological and Environmental Samples

et al. 2003

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A systematic study of the efficiency of protons, Ni, Pd and Th as chemical modifiers for the determination of cadmium by electrothermal atomic absorption spectrometry (ETAAS) using fast temperature programs was made for platform atomization. A comparison was made in terms of the salt type, absorbance-time profiles and elimination of the sodium chloride interference. The results were adapted to develop a method for the ETAAS determination of cadmium in biological and environmental samples. The highest sensitivity to determine cadmium in biological and environmental samples was obtained using nickel (together with protons) as a chemical modifier. The accuracy of the method was tested by the determination of cadmium in different certified reference materials. The best detection limit and the characteristic mass of Cd were found to be 0.03 ng mL -1 and 0.35 pg, respectively.

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“…Other platinum group metals and oxide/carbide-forming elements, have also been used to good effect as modifiers in ETAAS. [8][9][10] Thorium has been shown to work successfully when added in solution as a single chemical modifier for the determination of arsenic 9,10 in samples containing aluminium, such as coal fly ashes. It is well known that aluminium can cause severe interferences in the determination of arsenic by ETAAS.…”

Section: Introductionmentioning

confidence: 99%

Spectrometric study of condensed phase species of thorium- and palladium-based modifiers in a complex matrix for electrothermal atomic absorption spectrometry

Castro

Aller

McCabe

et al. 2007

J. Anal. At. Spectrom.

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The chemical and morphological transformations of condensed phase species of a thorium-based modifier were studied over the temperature range 200-2500 1C, without and with the presence of aluminium and silicon as matrix components, and in some instances, arsenic as an analyte element. A similar study was also conducted with palladium as the modifier, for comparison. Results were derived using scanning electron microscopy (SEM), energy dispersive (ED) X-ray spectrometry, Raman microanalysis and attenuated total reflectance (ATR) Fourier transforminfrared (FT-IR) spectrometry. Comparable results were found using pyrolytic and non-pyrolytic graphite platforms, with processes occurring at slightly higher temperatures on the pyrolytic graphite platform. With thorium as the modifier, metal oxides were the predominant species on the platform surface at relatively low temperatures (o1500 1C), whereas metal phases became prevalent at high temperatures, when thorium and aluminium tended to behave independently from one other. Some spatial variations in the composition of the salt residues on different regions of the platform were observed (from the region closest to the slot in the tube, to the region furthest from the slot). Nonetheless, thorium metal remained on the graphite platform to higher temperatures than did aluminium metal. In the presence of arsenic, the existence of mixtures of thorium and arsenic oxides, just before the appearance temperature of gas phase arsenic atoms, was confirmed by SEM studies, ED X-ray spectra and Raman microanalysis. This suggests that any modifying effect of thorium on arsenic occurs while the modifier is in the oxide phase rather than in the metal phase. The presence of silicon added as silica, did not influence significantly the thermochemical behaviour of mixtures of thorium and aluminium. However, coexistence of silicon and arsenic oxides at the appearance temperature of the atomic absorption signal of arsenic was obtained, confirming that silicon can act as an internal modifier for arsenic. In the presence of palladium, aluminium exhibited greater interaction with the modifier; consequently, aluminium metal was retained on the platform surface to higher temperatures than thorium, which could explain how interference effects of aluminium on e.g. arsenic are avoided or reduced. Similarly, there was evidence for interaction of palladium and arsenic in the reduced state. However, when aluminium and silicon were present, the transformation of the palladium oxide to the metallic state was affected, which could diminish the modifying benefits of palladium for arsenic in the presence of aluminium.

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Behavior of thorium, zirconium, and vanadium as chemical modifiers in the determination of arsenic by electrothermal atomization atomic absorption spectrometry

Cited by 20 publications

References 23 publications

Effect of the Chemical Species of Arsenic on Sensitivity in Graphite Furnace Atomic Absorption Spectrometry

Effect of the Chemical Species of Arsenic on Sensitivity in Graphite Furnace Atomic Absorption Spectrometry

Nickel as a Chemical Modifier for Sensitivity Enhancement and Fast Atomization Processes in Electrothermal Atomic Absorption Spectrometric Determination of Cadmium in Biological and Environmental Samples

Spectrometric study of condensed phase species of thorium- and palladium-based modifiers in a complex matrix for electrothermal atomic absorption spectrometry

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