Hydrogen Sulphide Quantification By Sift/Ms: Highlighting The Influence Of Gas Moisture

The quantification of hydrogen sulphide (H2S) by Selected Ion Flow Tube coupled with Mass Spectrometry (SIFT/MS) was investigated for application in industrial emission context, usually faced with concentrations of water vapour higher than the saturation at room condition. H2S concentrations measured by SIFT/MS (using nitrogen as carrier gas and flow tube temperature at 119 degrees C) were affected by water content, reducing the sensibility for H2S measurements. Accurate concentrations were obtained when the influence of water was considered on SIFT/MS analysis, requiring although the information about water content in the sample. In addition, the association of low concentration of H2S (around 50 ppbv) and high humidity level (4.0 %vol of water) was highlighted as a critical point for measuring H2S by SIFT/MS, due to the sensibility reduction as function of water content and the measurement uncertainty enhancement at low signal intensity.