The UV Fluorescence method is the most simple and practical low-level sulfur analytical technique. It has been widely used and proven over many years of use in industrial settings. This method involves injection of a sample into a high-temperature oxidation furnace, converting all hydrocarbons into water (H2O) and carbon dioxide (CO2). Total sulfur contained in molecular-bound hydrocarbon species is oxidized at temperatures in excess of 1000°C into sulfur dioxide (SO2) by the reaction:
The furnace effluent containing these combustion byproducts is directed into a detection chamber where it is excited by high-energy, short-wavelength emission from the EUVF of Excimer UVF source. The UV photons from the excitation source, transfer energy into the SO2 molecule and raise its energy level to create an excited singlet state. These excited molecules rapidly decay back to their lower energy ground state releasing the absorbed energy as a secondary emission known as fluorescence.
Fluorescence emission is optically filtered to remove undesired wavelengths from excitation source and background scatter within the detector chamber. Detection of filtered fluorescence emission is accomplished using a Photomultiplier Tube and amplified by proprietary high sensitivity electronics.