title: Detection of mercuric chloride by photofragment emission using a frequency-converted fiber amplifier.
abstract: A real-time, noninvasive approach for detecting trace amounts of vapor-phase mercuric chloride (HgCl(2)) in combustion flue gas is demonstrated using a near-infrared pulsed fiber amplifier that is frequency converted to the ultraviolet. Excitation of the HgCl(2) ([see text]) transition at 213 nm generates 253.7 nm emission from the Hg (6(3)P(1)) photoproduct that is proportional to the concentration of HgCl(2). A measured quadratic dependence of the HgCl(2) photofragment emission (PFE) signal on the laser irradiance indicates that the photodissociation process involves two-photon excitation. Additionally, low concentrations of HgCl(2) are detected with the PFE approach in an environment characteristic of coal-fired power-plant flue gas using this compact solid-state laser source. A detection limit of 0.7 ppb is extrapolated from these results.
authors.affiliation: Sandia National Laboratories, P.O. Box 969, MS 9056, Livermore, California 94551, USA. aahoops@sandia.gov
authors.forename: Alexandra A
authors.initials: AA
authors.lastname: Hoops
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Reichardt
authors.forename: Dahv A V
authors.initials: DA
authors.lastname: Kliner
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Koplow
authors.forename: Sean W
authors.initials: SW
authors.lastname: Moore
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000669:Amplifiers, Electronic; D003031:Coal; D004784:Environmental Monitoring / Q000379:methods*; D005740:Gases; D007834:Lasers; D008027:Light; D008627:Mercuric Chloride / Q000032:analysis*; D008628:Mercury / Q000737:chemistry* / Q000633:toxicity*; D015233:Models, Statistical; D055095:Optics and Photonics; D052638:Particulate Matter; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D000393:Air Pollutants; D003031:Coal; D005740:Gases; D052638:Particulate Matter; D008627:Mercuric Chloride; D008628:Mercury