The TD-GC-Lonestar system sold by Owlstone Medical Ltd gives the capability to analyse thermal desorption tubes using FAIMS on the Lonestar equipment. The Gas Chromatograph (GC) system used is the Thermo Trace 1310 and the thermal desorption (TD) used is the Markes UNITY-xr.
Samples are loaded onto the tube oven, which heats the tube and applies a backflush of clean Helium (carrier) gas. The He flow drives the sample towards a focusing cold trap (Markes U-T12ME-2S), which is packed with Tenax and Carbograph. The cold trap splits and recollects the analytes. A second desorption step takes place on the cold trap, in where a backflush of He transports and introduces the re-collected sample into the GC column via a transfer line.
The U-T12ME-2S Cold Trap is usually used with the temperature ranging from 290-320°C, with maximum operating temperature is 335°C that never should be exceeded. The cold trap requires to be blanked periodically, preferably daily, to assess trap saturation and to prevent sample carryover. Sample carryover is due to sample accumulation, which can affect following sample analysis.
This user guide gives guidelines on how to run and evaluate a cold trap blank in the TD-GC-LNS system.