Chemiluminescence from Sulfur Compounds in Novel Flame and Discharge Systems: Proof of Sulfur Dioxide as the Emitter in the New Sulfur Chemiluminescence Detector

Gases from a hydrogen-rich, sulfur-dioxide-containing, hydrogen/oxygen flame were drawn into a reduced-pressure reaction vessel and reacted with ozone. Spectroscopic analysis of the low-pressure chemiluminescence showed that electronically excited sulfur dioxide is the principal emitter exploited in the new sulfur chemiluminescence detector (SCD). Sulfur dioxide phosphorescence was found to contribute significantly to the total emission, suggesting that the technique could be enhanced by detecting more of the phosphorescence at higher total pressures. A calibration plot of signal vs. sulfur dioxide concentration was found to have a slight positive curvature. Interferences from NO 2 * and OH* were spectroscopically characterized; it is suggested that these could be minimized in the SCD by judicious choice of the wavelength discrimination filter. Utilization of a microwave discharge was similarly efficient at producing the chemiluminescence.