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