Comparison of internal energy distributions generated by supercritical fluid chromatography versus liquid chromatography hyphenated with electrospray high resolution mass spectrometry.

The internal energy distributions of thermometer ions dissolved in supercritical and liquid solvents and produced in the gas phase by electrospray (ESI) were measured and compared by the survival yield method. The influence of different chromatographic conditions such as the nature of solvents, the composition of the mobile phase, the pressure of the back pressure regulator was studied for supercritical fluid chromatography (SFC) whereas the influence of the composition and of the flow rate of the mobile phase was investigated for liquid chromatography (LC). The MS instrumental parameters were studied in parallel for SFC and LC showing that the drying gas temperature and the fragmentor voltage affected the internal energy distribution, whereas the capillary voltage did not modify the internal energy distribution. A comparison of the internal energy distributions generated by SFC and LC was carried out leading to conclude that SFC led to higher internal energy, i.e. more in-source fragment ions, than LC.