Parameter Evaluation for the Analysis of Oxide-Based Samples with Radio Frequency Glow Discharge Mass Spectrometry

Abstract

The performance of radio frequency-powered glow discharge mass spectrometry (rf-GDMS) has been evaluatedfor the direct analysis of nonconducting samples. The parameters under study are the discharge power, the discharge pressure, the sample versus exit orifice distance, and the effect of cryogenic cooling. Optimum conditions are used to evaluate some analytical figures of merit for the analysis of compacted oxide-based materials. A precision of better than 5% is obtained on all measured species in the discharge, and a semiquantitative analysis delivers results within a factor of 2 from the certified concentrations. Relative sensitivity factors are reported and compared for various matrices. The analytical data demonstrate the potential capabilities of rf-GDMS for direct analysis of various kinds of nonconducting materials.Glow discharge mass spectrometry (GDMS) has developed rapidly in recent years as a technique for the elemental analysis of solid samples. The great majority of that work has used a direct current (dc) glow discharge, although attention is now turning to a radio frequency (rf) discharge. More than two decades ago, Cobum and Kay1 showed that a combination of rf glow discharge sputtering and mass spectrometry allowed elemental analysis of thin surface layers for either conducting or insulating matrices.They reported comparable sensitivities for almost all elements.Studies by Donohue and Harrison,2 who modified a spark source mass spectrometer to power an rf hollow cathode discharge ion source, indicated that similar spectra and sensitivities were obtained for dc and rf discharges, with the latter having the added advantage of sampling insulators directly.

Critical revision of GD-MS, LA-ICP-MS and SIMS as inorganic mass spectrometric techniques for direct solid analysis

“…GD-SFMS instruments are currently the only GD-MS commercially available and are manufactured by Thermo Fischer Scientific with a fast-flow Grimm-type GD cell. Alternatively, time-of-flight (TOF) mass analyzers offer many interesting features: (i) quasi-simultaneous detection of a large mass range, from hydrogen to macro-molecules, 115 (ii) higher mass resolving power compared to a quadrupole MS, 116 (iii) lower cost compared to high resolution SFMS and (iv) high spectral acquisition rate that allows the measurement of transient ion signals. 117 Taking into account these unique properties of time-of-flight mass analyzers, the use of GD-TOFMS offers great potential in the area of depth profiling analysis, especially for thin layers where the composition of the sample changes rapidly with time and the quasi-simultaneous multi-analyte determination of many isotopes should be carried out at every sample depth.…”

Special feature: Tutorial. Glow discharge mass spectrometry: Trace element determinations in solid samples

“…55 The various expansions in scale clearly show the minor components in the Ðrebrick sample. Semiquantitative ion beam ratio results yield concentrations that are within a factor of two of the certiÐed values.…”

Inorganic mass spectrometry as a tool for characterisation at the nanoscale

“…At present, GD-SFMS instruments are the only GD-MS instruments commercially available and are manufactured by Thermo Fischer Scientific. Alternatively, TOF mass analysers offer interesting features, such as quasisimultaneous detection of a large mass range (from H to macromolecules), higher mass resolving power compared with QMS, lower cost compared with high-resolution SFMS and a high spectral acquisition rate, which allows the measurement of transient ion signals [52,53], thus offering a great potential for thin and ultrathin solid films [54]. GD-TOFMS systems are not yet commercially available, although new prototypes are currently under development in a European project (EU through FP6 contract STREP-NMP).…”