Glow-discharge mass spectrometry GD-MS

There is a branch of MS specially designed for dealing with the analysis of inorganic materials.[21,22] Different specific ionization techniques, such as inductively coupled plasma mass spectrometry (ICP-MS),[23] glow discharge mass spectrometry (GD-MS)[24] and secondary ion mass spectrometry (SIMS),[25] are available and they are widely used in cultural heritage applications. Their description is beyond the scope of this chapter. 

For analysis of solutions, ICP-mass spectrometry (ICP-MS) is very promising (Houk et al., 1980 Houk, 1986 Bacon et al., 1990). Recent advances in separation and preconcentration techniques are discussed by Horvath et al. (1991). Bacon et al. (1990) report that although ICP-MS is a multi-element technique, recent papers tend to concentrate on a small number of target elements. With isotope dilution mass spectrometry (IDMS), detection limits are further reduced (Heumann, 1988) IDMS is also suitable for accurate speciation in very low concentration levels of elements (Heumann, 1990). For the direct analysis of solid samples, glow discharge mass spectrometry (GD-MS) (Harrison etal., 1986) is of interest. Tolg (1988) has suggested that a substantial improvement in the absolute detection power of GD-MS, as applied to micro analysis, can be expected, at least in comparison with the ICP as ion source. 

Figure 1 Glow discharge mass spectrometry (GD-MS) spectrum of a mixture of rare earth oxides compacted in a tantalum host matrix. Oxide composition 5% by weight in disk, each element present at 110 ppm. (From Ref. 39.)...

Figure 3 Schematic representation (not to scale) of the source assembly used in the secondary cathode approach to glow discharge mass spectrometry (GD-MS) analysis of nonconductive samples. (From Ref. 21.)...

In the course of the late 1970s new mass spectrometric methods, which made use of the plasma sources known from optical atomic spectrometry came into use. They will be treated in detail and consist in particular of ICP mass spectrometry (ICP-MS) and glow discharge mass spectrometry (GD-MS), which have contributed to a considerable portion of the progress that has been made in elemental analysis as compared with spark source mass spectrometry. 

The concentration of impurities in the powder was determined by Glow Discharge-Mass Spectrometry (GD-MS). Only those impurities exceeding a concentration of 1 ppm by weight are listed. The impurity levels are within the specifications for this material except for chlorine which is present at about twice the concentration generally found in this lX)wder. A comparison of the data for riffled and unriffled samples shows that, at least within the accuracy and precision of this analytical technique, there is no difference in the contaminant levels. 

A.10.3.1 GD-MS, GD-OES, and ICP-MS Glow Discharge Mass Spectrometry (GD-MS) is a destructive mass spectrometric technique that provides ultra-trace... 

Table 8.60 shows the main features of GD-MS. Whereas d.c.-GD-MS is commercial, r.f.-GD-MS lacks commercial instruments, which limits spreading. Glow discharge is much more reliable than spark-source mass spectrometry. GD-MS is particularly valuable for studies of alloys and semiconductors [371], Detection limits at the ppb level have been reported for GD-MS [372], as compared to typical values of 10 ppm for GD-AES. The quantitative performance of GD-MS is uncertain. It appears that 5 % quantitative results are possible, assuming suitable standards are available for direct comparison of ion currents [373], Sources of error that may contribute to quantitative uncertainty include sample inhomogeneity, spectral interferences, matrix differences and changes in discharge conditions. 

FFF Field-flow fractionation GD-(MS) Glow-discharge (mass spectrometry)... 

Figure 7 Radio frequency glow discharge mass spectrometry (rf GD-MS) source designs employed on a VG GloQuad instrument for the analysis of a, Pin-type samples. (From Ref. 28.) b, Flat samples. (From Ref. 29.)...

Depth profiling with LA-ICP-MS has not yet been optimized to its full potential [39,40], but it might be already considered complementary to other methods (e.g., glow discharge mass spectrometry or optical spectrometry [GD-MS/OES] and SIMS). 

Notes TIMS, thermal ionization mass spectrometry ICP-MS, inductively coupled plasma mass spectrometry GD-MS, glow discharge mass spectrometry XRF, x-ray fluorescence XRD, x-ray diffraction GC-MS, gas chromatography-mass spectrometry SEM, scanning electron microscope TEM, transmission electron microscope SIMS, secondary ion mass spectrometry EDS, energy-dispersive sensor WDS, wavelength-dispersive sensor. 

Figure 19 Schematic diagram of the microsecond pulsed glow discharge time-of-flight mass spectrometry (GD-TOF-MS) system. (From Ref. 55.)...

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