Sequential monitoring of elemental mercury in stack gas by dielectric barrier discharge micro-plasma emission spectrometry

Advances in dielectric barrier discharge-optical emission spectrometry for the analysis of trace species

“…Similarly, a simple device involving on-line gold amalgam preconcentration, external thermal desorption and cold excitation in an enclosed atmospheric-pressure DBD chamber was constructed for on-site sequential monitoring of emitted Hg 0 in coal-red stack gas. 29 It was noted that Hg 0 was efficiently and selectively trapped on the gold amalgam at <220 C, and could be released rapidly at a temperature of >420 C. A linear calibration graph was achieved within 8-256 ng (the mass of enriched Hg 0 on the gold trapping micro-column) with a detection limit of 2.3 ng by DBD-OES measuring the mercury atomic emission at 253.7 nm.…”

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

“…2. The strong spectral band at approximately 308 nm was attributed to the emission of Ar molecules [21]. With the open-ended source, only the H 2 S emission line at 365.06 nm arising from air; the others merged completely with the background spectrum.…”

“…If fact, Hg 0 weak excitation line at approximately 365 nm was very difficult to be detected (shown in Supplementary Fig. 1) without gold amalgam enrichment [21]. Therefore, the application of the analytical system to the determination of H 2 S in real samples can be evaluated via the determination of the H 2 S generated by S 2 À .…”

“…In addition, reactions between the target gaseous molecules and fragments of air were avoided and the optical-fiber probe was protected. The enclosed DBD molecular emission spectrometry (DBD-MES) was successfully applied to the determination of ammonia and provided a good performance in terms of a clear emission background, high sensitivity and precision [21]. This enclosure enables the determination of inorganic small gas molecules by DBD-MES, and further application of this system, combined with appropriate sample treatment, to the determination of pollutant gases in the atmosphere, i.e., H 2 S, is desirable.…”

“…However, a complex background spectrum strongly restricts such determinations when the analyte emission lines are primarily in the violet region. Recently, an enclosed-DBD microplasma device was developed in which a quartz window was used to seal the hollow discharge chamber from the outside atmosphere [20,21]. In the enclosed excitation mode, spectral interferences from ambient air during excitation were effectively eliminated.…”