2.2 GC equipment requirements
UNITY-xr is usually connected to a gas chromatograph configured with appropriate conventional or mass
spectrometer (MS) detectors. No conventional GC injector is required for UNITY-xr operation. Ready and
external start connections are required on the GC.
2.2.1 Access into the GC oven
The UNITY-xr heated transfer line is lined with 0.25 mm I.D., 0.35 mm O.D. uncoated deactivated fused
silica which butt connects with the capillary analytical column inside your GC oven.
It is important that the heated and insulated portion of the transfer line extends as far as the skin of the
GC oven such that the GC oven heating begins at the point where heating of the transfer line ends. A 25
mm diameter access hole is thus required into the GC, with a 6.5 mm hole in the GC inner oven
wall. Further information is provided in Section 3.5.
2.2.2 GC configuration/parameter selection
From a GC perspective, UNITY-xr may simply be regarded as a multipurpose, stand alone GC injector for
capillary or 1/8 inch packed columns. No conventional GC injector is required for UNITY-xr operation. The
rest of the GC system - column, oven, data handling, detector, etc. - should be configured and used, as per
normal chromatographic practice for the analytes of interest.
If multiple applications are to be carried out or if samples are uncharacterised; for example when
monitoring unknown atmospheres, a good general purpose GC configuration comprises 25-30 m, 0.25mm
or 0.32 mm ID, 1 or 2 µm phase thickness bonded methyl silicone capillary column with a FID or mass
spectrometer detector.
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