Scanning Electron Microscopy (SEM) analysis of the JFTOT tubes was carried out using a JEOL 6490LV SEM.
The JFTOT fuel samples were dipped onto the closed end of the Dipit- capillary tubes[TM] (IonSense) and positioned on a rack between the DART ion source and detector inlet (Figure 3).
An external standard of caffeine was used and placed on a Dipit- tube to calibrate the position of the JFTOT tube.
The JFTOT rods had to be sampled directly from the metal surface of the rod.
There are two distinct different chemistries on the surface of the example JFTOT tube, observed in (Figure 27).
Initial studies with DART used a ULSDB20 JFTOT deposit and caffeine as marker (Figure 32) and looked at the influence of temperature on the spectrum.
From (Figures 32 and 33) it is clear that as higher temperatures are applied to the JFTOT tube then higher molecular weight compounds are volatilized from the tube.
Note the FT-ICR-MS before and after JFTOT figure show as expected a reduction of molecular species after the JFTOT tubes.
In summary, the FTICRMS spectra show some oxidation species pre JFTOT and more post JFTOT.
The ULSD JFTOT tube yield little of interest in this initial study even at 400[degrees]C.
The techniques described have been proven to be useful in the characterization of JFTOT deposits from diesel fuel, allowing characterization of a ULSD, B20 and a layered mixed ULSD B20 deposit.
DARTMS: This has been shown to be a promising technique in the analysis of diesel deposits on JFTOT tubes.