Limits...
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.


Effect of He addition on oxygen sensitivity
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4225055&req=5

Fig8: Effect of He addition on oxygen sensitivity

Mentions: In the first stage, the Ar and He flows were fixed at 280 and 40 sccm, respectively, obtaining a total gas flow of 320 sccm, which is the flow used for routine analysis of Al samples in pure Ar. In such a situation, the voltage increases considerably and it is not possible to evaluate higher concentrations of He because the maximum voltage is reached and then the fixed current (80 mA) cannot be achieved. Afterwards, aiming to reduce the voltage, the Ar flow was maintained at 320 sccm while the He concentration was increased to 40 sccm resulting in a total flow of 360 sccm. The oxygen calibration curves obtained in pure Ar and the above mentioned gas mixtures are shown in Fig. 8. As can be seen, the variations of sensitivity are not significant (<4 %). It should be mentioned that Lange [28] observed improvements of sensitivity for He concentrations between 20 and 30 % v/v. However, in our experiments, we cannot go above 15 % v/v of He without modifications of the current and flow conditions.Fig. 8


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)

Effect of He addition on oxygen sensitivity
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4225055&req=5

Fig8: Effect of He addition on oxygen sensitivity
Mentions: In the first stage, the Ar and He flows were fixed at 280 and 40 sccm, respectively, obtaining a total gas flow of 320 sccm, which is the flow used for routine analysis of Al samples in pure Ar. In such a situation, the voltage increases considerably and it is not possible to evaluate higher concentrations of He because the maximum voltage is reached and then the fixed current (80 mA) cannot be achieved. Afterwards, aiming to reduce the voltage, the Ar flow was maintained at 320 sccm while the He concentration was increased to 40 sccm resulting in a total flow of 360 sccm. The oxygen calibration curves obtained in pure Ar and the above mentioned gas mixtures are shown in Fig. 8. As can be seen, the variations of sensitivity are not significant (<4 %). It should be mentioned that Lange [28] observed improvements of sensitivity for He concentrations between 20 and 30 % v/v. However, in our experiments, we cannot go above 15 % v/v of He without modifications of the current and flow conditions.Fig. 8

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.