title: Detection of HCl and HF by TTFMS and WMS.
abstract: In this work we discuss on a compact spectrometer based on DFB diode lasers for detection of chloridric and fluoridric acids. HCl and HF concentrations are determined through optical absorption of the P(4) line (lambda=1.7 microm) and the R(3) line (lambda=1.3 microm), respectively. Both lines belong to first overtone vibrational bands and their line strengths are 7.8 x 10(-21)cm/molecule for HCl and 2.8 x 10(-20)cm/molecule for HF. We chose these lines for their relative high intensities and because they are quite far from water vapour lines which represent the main interfering gas for trace-gases analysis. To detect these species we used two different high frequency modulation techniques: two-tone frequency modulation spectroscopy (f(1)=800 MHz and f(2)=804 MHz) was used for HCl while for HF we followed a simpler approach based on wavelength modulation spectroscopy (f=600 kHz). We demonstrate that the two techniques provide comparable detection limit of about 80 ppbV at atmospheric pressure. Positive testing of our spectrometer makes it suitable for in situ measurements of exhaust gases coming from waste incinerators.
authors.affiliation: Dipartimento di Scienze Fisiche, Università di Napoli "Federico II", Complesso Universitario M.S. Angelo, via Cinthia 80126 Napoli, Italy.
authors.forename: Anna Chiara
authors.initials: AC
authors.lastname: De Luca
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pesce
authors.forename: Giulia
authors.initials: G
authors.lastname: Rusciano
authors.forename: Antonio
authors.initials: A
authors.lastname: Sasso
mesh_terms: D006851:Hydrochloric Acid / Q000032:analysis*; D006858:Hydrofluoric Acid / Q000032:analysis*; D007834:Lasers; D013057:Spectrum Analysis
chemical_list: D006851:Hydrochloric Acid; D006858:Hydrofluoric Acid