The GC/MS we use is a GC/MS system conisting of a 5977E MSD single-quadrupole mass spectrometer with a 7820A GC by Agilent Technologies. It consists of a gas chromatography equipped with a column suitable for analyte solutions in nonpolar, volatile solvents like hexane. Solutions in water or high boiling solvents will destroy the injection system as well as the column.
The samples have to be free of any salts and must contain highly volatile compounds only. As solvents for the samples, THF, diethyl ether, esters and hexane or propane are recommended. Again, aqueous solutions can´t be analyzed with this instrument.
Since the ionization is taking place after chromatographic separation, all analytes are gaseous already. Electron impact (EI) is used. The resulting mass spectra usually contain a lot of fragment ions (odd and even electron ions) as well as M*+ radical ions for the lucky ones. Just low resolution measurements are possible (R ≈ 1,000), since a single quadrupole is used as analysator. Further limiting is the mass range of approx. m/z 20 to 650. This drawback is partly compensated by the possibility of automatic comparison of the generated spectra with a data base.
Users may perform measurements on their own after some training (open-access instrument).