Gas Chromatography - Tandem Techniques - Examples of GC/MS Spectrometry Applications > Analysis of Waxes and Lipid Type Materials > Page 76

 

The GC/MS analysis was performed on a Pye 204 GC in conjunction with VG double focusing magnetic sector mass spectrometer and a Finnigan INCOS 2300 data system. The transfer line was maintained at 350ūC, the ion source at 300ūC and the electron impact ionization took place at 70 eV. The total ion current of a potsherd extract is shown in figure 61. It is seen that an interesting selection of lipid materials has been extracted from the potsherd. according to the authors, the technique is now a routine procedure for ceramic materials found at the various archaeological site under investigation at that time.

 

 

Figure 61. Total Ion Current Chromatogram of the Lipids from a Potsherd from a Late Saxon Ditch (after ref 22)

 

C. de St. Etienne and J. Mettes (23) used the GC/MS instrument to assay the purity of silane. Silane of high purity is essential to the electronics industry for the fabrication of integrated circuits and as amorphous silica in photovoltaic applications. The author used a IGC gas chromatograph fitted with a katherometer detector and a packed stainless steel column, 13.2 m long, 3.17 mm I.D., containing Chromosorb PAW 45/60 mesh, coated with 28% of DC 200 stationary phase. Helium was used as the carrier gas at a flow rate of 20 ml/min. The column eluent was split through a low-dead-volume splitter directly to the mass spectrometer. The mass spectrometer was a Riber AQX 156 quadrapole filter having a mass range of 0-300. Electron impact ionization was employed with energies of 70 eV, and the mass spectrometer ion source was maintained at about 100ūC. An example of the total ion current chromatogram of a crude silane sample is shown in figure 62.