1992 Volume 8 Issue 2 Pages 173-177
The response characteristics of flame thermionic detectors (FTDs) to sulfur compounds were studied. The optimum flow rates of air and hydrogen were obtained by investigating changes in the detector response and selectivity for hydrocarbons with respect to changes in the air and hydrogen flow rates. From these investigations, the response for sulfur compounds shows a high sensitivity at an air flow rate of about 6ml min-1, as well as 100ml min-1 or 16ml min-1. Investigations were carried out concerning the detection limit, response linearity and selectivity for representative sulfur compounds (under these set of operational conditions). Disulfides were detected at especially high sensitivity, under 16ml min-1 air flow rate conditions. The detection limit of dimethyl disulfides was 1.78×10-10g s-1 (S/N=2), and the selectivity for hydrocarbons was 1.7×103gC/gS. Exact details concerning the negative surface ionization process on alkali metal surface are not completely known. The presumed ionization process for organic sulfur compounds is discussed in this paper.
