UV-Fluorescence

When a Sulfur containing sample is combusted at 1000 ℃, Sulfur dioxide (SO2) is formed:

R-S + O2 --> SO2 + H2O + CO2

The amount of Total Sulfur is measured by pulsed UV-Fluorescence detection technique. Applying this detection technique together with combustion of a given sample proceeds as followed:

Sulfur dioxide (SO2) is formed during oxidation and transferred to the reaction chamber. Here it is excited by a pulsed UV source and as the excited state is unstable, the excited SO2 instantly decays to its ground state energy level. During this process, UV light is emitted. As this light has a different wavelength than the orginial UV source, the Photomultiplier tube is able to detect this emission.

The amount of light emitted reflechts the total amount of SO2 present in the combusted sample flow, which in turn correspond the amount of Total Sulfur in the sample.

The equations for this reaction are:

SO2 + hv1 --> SO2*

SO*2 --> SO2 + hv2

High amounts of Nitrogen present in the sample could interfere with the amount of Total Sulfur given by a Elemental Combustion Analyzer, especially when measuring at trace level. TE Instruments developed a solution to prevent this from happening. For additional information regarding this solution, please contact our Sales Team: sales@teinstruments.com

Elemental Combustion Analyzers that make use of this detection technique: XPLORER-S, XPLORER-NS

International methods carried out by using this technique: ASTM D6667, ASTM D5453, ASTM D7183, ISO 20846, SH/T 0689