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

Abstract

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 NO2* 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.

Flow Tube Kinetics Investigation of the Mechanism of Detection in the Sulfur Chemiluminescence Detector

“…Since that early work, three electronically excited states ( ã 3 B 1 , à 1 A 2 , and B̃ 1 B 1 ) of SO 2 have been relatively well characterized. , The à and B̃ states both contribute to a broad fluorescence continuum in the wavelength range 280−380 nm with markedly different lifetimes and quenching rate constants. Glinski et al have shown that the phosphorescent state ( ã 3 B 1 ), which provides a highly characteristic banded emission in the wavelength range 380−460 nm, is not produced directly in the chemiluminescent reaction but is formed through collisionally induced intersystem crossing from one of the singlet states. , Both Benner 1 and Martin and Glinski found that the emission spectrum of SO 2 * obtained in the reaction of the effluent of a SO 2 -doped, hydrogen-rich flame with ozone matched extremely well the emission spectrum produced in the reaction of SO with ozone, where SO was produced by fragmentation of SO 2 in a microwave discharge.…”

Molecular spectroscopy – Information rich detection for gas chromatography

“…Reduced pressure oxidation with O3 in the ozone reactor [191]: The NCD and SCD are analogous technologies in respect of their design and implementation, and are conceptually similar in their underlying chemical processes and performance.…”

Unique selective detectors for gas chromatography: Nitrogen and sulfur chemiluminescence detectors

“…Readers are referred to the cited references for more detailed discussions on this topic. However, it has been established that the ultimate emitter of the chemiluminescence in SCD, which is the intermediate product of the reaction between ozone and the sulfur chemiluminescent species, is invariably an excited SO 2 * molecule [30]. Regardless of the identification, the mechanism of the chemiluminescence detection step, with the sulfur chemiluminescent species generically denoted as X -S, can be expressed as the following.…”