Cold excitation and determination of hydrogen sulfide by dielectric barrier discharge molecular emission spectrometry

Abstract A low-temperature microplasma generated in a dielectric barrier discharge (DBD) was used as a radiation source for the excitation of hydrogen sulfide and its determination by molecular emission spectrometry (MES). The excitation/emission chamber was enclosed to eliminate spectral interference from ambient air. The spectral emission lines of hydrogen sulfide were clearly discriminated from the background spectrum, and the emission line at 365.06 nm was selected for parameter optimization and quantitative analysis. The S^2- ions in aqueous samples were reacted with acid to generate hydrogen sulfide and then determined. The experimental parameters affecting the determination of hydrogen sulfide and S^2- were optimized. The limits of detection were 1.4 mg m^-3 for H₂S and 11.2 mg L^-1 for S^2-. The repeatability of the method was satisfactory, as the RSD values were 2.3% for H₂S and 1.8% for S^2-. The enclosed DBD-MES system was demonstrated to be a useful tool for the determination of hydrogen sulfide in gas samples and S^2- in aqueous samples.