Experimental Mass spectra were acquired by using the InfiTOF with a multi-segment mode setting of 150 turns to give a resolving power of approximately 30,000 (FWHM) at m/z 18. Additionally, the ionizing electron voltage was set to 15 eV. Figure 1 shows a schematic drawing of the experimental equipment. A 22mL mixing vial was set up between the gas chromatograph and the mass spectrometer. A deactivated fused-silica capillary tube (3m x 0.25mm) was used for the GC – vial connection, and a deactivated fused-silica capillary tube (30cm x 0.1mm) was used for the vial – MS connection. The GC helium gas flow rate was set to 1mL/min.