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The use of matrix-specific calibrations for oxygen in analytical glow discharge spectrometry.

Gonzalez-Gago C, Smid P, Hofmann T, Venzago C, Hoffmann V, Gruner W - Anal Bioanal Chem (2014)

Bottom Line: The importance of a "blue shifted" line of oxygen at 130.22 nm (first reported by Köster) for quantitative analyses by GD-OES is confirmed.Matrix-specific calibrations for oxygen in GD-MS are presented.Additional experiments using Ar-He mixtures or μs pulsed GD are carried out in ELEMENT GD aiming to improve the oxygen sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute for Solid State and Materials Research (IFW) Dresden, P.O. Box 270116, 01171, Dresden, Germany.

ABSTRACT
The performance of glow discharge optical emission spectroscopy and mass spectrometry for oxygen determination is investigated using a set of new conductive samples containing oxygen in the percent range in three different matrices (Al, Mg, and Cu) prepared by a sintering process. The sputtering rate corrected calibrations obtained at standard conditions for the 4 mm anode (700 V, 20 mA) in GD-OES are matrix independent for Mg and Al but not for Cu. The importance of a "blue shifted" line of oxygen at 130.22 nm (first reported by Köster) for quantitative analyses by GD-OES is confirmed. Matrix-specific calibrations for oxygen in GD-MS are presented. Two source concepts-fast flow (ELEMENT GD) and low gas flow (VG9000)-are evaluated obtaining higher sensitivity with the static flow source. Additional experiments using Ar-He mixtures or μs pulsed GD are carried out in ELEMENT GD aiming to improve the oxygen sensitivity.

No MeSH data available.


Matrix-specific calibration for oxygen in GD-OES: a Al-matrix; b Cu-matrix; c Mg-matrix. The samples were measured at standard conditions for the 4-mm dc source (700 V, 20 mA). The horizontal lines represent the relative intensities corresponding to the pure sintered samples. Note that different scales are used
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Fig2: Matrix-specific calibration for oxygen in GD-OES: a Al-matrix; b Cu-matrix; c Mg-matrix. The samples were measured at standard conditions for the 4-mm dc source (700 V, 20 mA). The horizontal lines represent the relative intensities corresponding to the pure sintered samples. Note that different scales are used

Mentions: The matrix-specific calibrations are presented in Fig. 2. In this form of calibration, the ratio of the intensities of oxygen and matrix lines is calculated after background subtraction and plotted versus the ratio of concentrations. In this way, changes in sputtering rates are corrected if the intensities depend linearly on the sputtering rate. The background of the oxygen line was measured at the higher wavelength part of the line profile (this will be discussed at the end of this section). For all samples, the initially weighed concentrations were used, which means that only the intentionally added oxygen from the oxides is taken into account. No error bars are shown in Fig. 2. However, the estimated relative error based on the multiple measurements on one crater is <10 %. The measurement at different positions of the sample however can cause a higher RSD because of sample inhomogeneity and small leakages. Additionally, the background concentrations of light elements improve during operation and degrade again afterwards. This could be the cause for higher oxygen background observed on the Cu samples where theoretically no oxygen should be present in comparison to the Mg and Al samples, measured also in this sequence. Investigations to reduce and quantify these additional sources of error are ongoing and will be published in due course. The relative intensities corresponding to the pure sintered samples were not considered for the calculation of the linear fitting since these samples contain a certain amount of oxygen (not voluntarily added). Nevertheless, these values are marked by horizontal lines in Fig. 2. Even if the exact concentrations of oxygen in the sintered pure Al and Mg samples is still not known, it is observed that they are at a higher level than in the sintered pure Cu sample (~150 μg/g determined by CGHE).Fig. 2


The use of matrix-specific calibrations for oxygen in analytical glow discharge spectrometry.

Gonzalez-Gago C, Smid P, Hofmann T, Venzago C, Hoffmann V, Gruner W - Anal Bioanal Chem (2014)

Matrix-specific calibration for oxygen in GD-OES: a Al-matrix; b Cu-matrix; c Mg-matrix. The samples were measured at standard conditions for the 4-mm dc source (700 V, 20 mA). The horizontal lines represent the relative intensities corresponding to the pure sintered samples. Note that different scales are used
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4225055&req=5

Fig2: Matrix-specific calibration for oxygen in GD-OES: a Al-matrix; b Cu-matrix; c Mg-matrix. The samples were measured at standard conditions for the 4-mm dc source (700 V, 20 mA). The horizontal lines represent the relative intensities corresponding to the pure sintered samples. Note that different scales are used
Mentions: The matrix-specific calibrations are presented in Fig. 2. In this form of calibration, the ratio of the intensities of oxygen and matrix lines is calculated after background subtraction and plotted versus the ratio of concentrations. In this way, changes in sputtering rates are corrected if the intensities depend linearly on the sputtering rate. The background of the oxygen line was measured at the higher wavelength part of the line profile (this will be discussed at the end of this section). For all samples, the initially weighed concentrations were used, which means that only the intentionally added oxygen from the oxides is taken into account. No error bars are shown in Fig. 2. However, the estimated relative error based on the multiple measurements on one crater is <10 %. The measurement at different positions of the sample however can cause a higher RSD because of sample inhomogeneity and small leakages. Additionally, the background concentrations of light elements improve during operation and degrade again afterwards. This could be the cause for higher oxygen background observed on the Cu samples where theoretically no oxygen should be present in comparison to the Mg and Al samples, measured also in this sequence. Investigations to reduce and quantify these additional sources of error are ongoing and will be published in due course. The relative intensities corresponding to the pure sintered samples were not considered for the calculation of the linear fitting since these samples contain a certain amount of oxygen (not voluntarily added). Nevertheless, these values are marked by horizontal lines in Fig. 2. Even if the exact concentrations of oxygen in the sintered pure Al and Mg samples is still not known, it is observed that they are at a higher level than in the sintered pure Cu sample (~150 μg/g determined by CGHE).Fig. 2

Bottom Line: The importance of a "blue shifted" line of oxygen at 130.22 nm (first reported by Köster) for quantitative analyses by GD-OES is confirmed.Matrix-specific calibrations for oxygen in GD-MS are presented.Additional experiments using Ar-He mixtures or μs pulsed GD are carried out in ELEMENT GD aiming to improve the oxygen sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute for Solid State and Materials Research (IFW) Dresden, P.O. Box 270116, 01171, Dresden, Germany.

ABSTRACT
The performance of glow discharge optical emission spectroscopy and mass spectrometry for oxygen determination is investigated using a set of new conductive samples containing oxygen in the percent range in three different matrices (Al, Mg, and Cu) prepared by a sintering process. The sputtering rate corrected calibrations obtained at standard conditions for the 4 mm anode (700 V, 20 mA) in GD-OES are matrix independent for Mg and Al but not for Cu. The importance of a "blue shifted" line of oxygen at 130.22 nm (first reported by Köster) for quantitative analyses by GD-OES is confirmed. Matrix-specific calibrations for oxygen in GD-MS are presented. Two source concepts-fast flow (ELEMENT GD) and low gas flow (VG9000)-are evaluated obtaining higher sensitivity with the static flow source. Additional experiments using Ar-He mixtures or μs pulsed GD are carried out in ELEMENT GD aiming to improve the oxygen sensitivity.

No MeSH data available.