Question

what challenges have to be addressed when using SFC in combination with either a UV or MS detector?

Answer 1

Supercritical Fluid chromatography (SFC) uses Carbon dioxide as the mobile phase for separating and detecting organic compounds. One of the challenges using SFC with UV detector is Carbon dioxide is completely transparent to UV below 190 nm. Above this wavelength, it is not transparent and hence can interfere with the analysis of the sample.

During interface with mass spectrometer (MS), the low pressure in the mass spectrometer makes the carbon dioxide evaporate which may lead to solute sticking on to the walls of the mass spectrometer. This is overcome by using a make-up pump delivering a small flow of modifier, usually methanol, to ensure none of the solutes stick to the walls of the transfer line