Organic sulphur compounds are known for their very low odour threshold value as well as their unpleasant smell. They also appear in very complex matrices (e.g. crude oil fumes). Therefore the FPD (Flame Photometric Detector), which is provided with a filter which only detects molecules with a binding between carbon and sulphur.
The gaseous sample is captured on an adsorbent especially made to hold organic sulphur compounds. The analysis is done with thermal desorption. After the separation of the compounds by the GC, a part of the gas is sent to the MS. The remaining gas flows through the FPD so both detectors measure the organic sulphur compounds simultaneous. When laying both chromatograms (from the MS and the FPD) on top of each other, the organic sulphur compounds, present in the sample, can be identified fast and very sensitive. The detected sulphur compounds are semi-quantified by calibrating 10 common sulphur compounds.