Gas Chromatography – Ion Mobility Spectrometer

Gas chromatography (GC) is an analytical technique used to separate and detect the components in a sample mixture. The GC is coupled to a Mass spectrometry (MS) where the neutral molecules eluted from the GC are ionized to produce molecular ions which degrade into fragment ions. Charged fragments are then separated in the mass analyzer by their mass to charge (m/z) ratio and are detected. The GC–MS is a GCMS-QP2020NX model (from Shimadzu, Kyoto, Japan) it is equipped by a capillary column SH-I-5 ms (30 m × 0.25 mm × 0.25 μm, Shimadzu, Kyoto, Japan). This is general purpose column suitable for untargeted analysis, the column can be changed in order to emphasise the detection of specific chemical families. The thermal cycle of the GC is totally customazable. The mass spectrometer is a single quadrupole operating in electron impact ionization mode, with an ionization energy of 70 eV. The detector operated with the full scan of mass ranging between 30 and 400 m/z. The instrument is complemented by the autosampler HT2800T (HTA HTA s.r.l., Brescia, Italy) that can accommodate up to 40 samples and equipped with a temperature control. The autosampler is compatible with enrichment phases such as SPME. GC–MS data are extracted using the included GCMSsolutions software (version 4.0, Shimadzu Corporation), that provide to the automatic chromatogram peak integration and putative compound identification. Putative peak identification is performed by comparison with standard libraries.

The instrument is suitable for the detection of thermally stable molecules with a molecular weight below 1250 Da. Main applications include Food analysis, environmental analysis, medical diagnosis.