Measurements of atmospheric nitrous acid and nitric acid |
| |
| Institution: | 1. Department of Mathematics and Physics, Catholic University of the Sacred Heart, Via della Garzetta 48, 25133 Brescia, Italy;2. Department of Civil Environmental and Mechanical Engineering (DICAM), University of Trento, Via Mesiano 77, 38123 Trento, Italy;3. Department of Science and Technology, Parthenope University of Naples, Centro Direzionale, Isola Block C4, 80143 Napoli, Italy;4. Department of Mathematics and Physics, University of Campania “Luigi Vanvitelli”, Viale Lincoln 5, 81100 Caserta, Italy;5. C3A - Center Agriculture Food Environment, University of Trento, Via Edmund Mach 1, 38010, San Michele all''Adige, Trento, Italy;1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;2. School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;3. Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Science, Xiamen 361021, China |
| |
| Abstract: | A highly sensitive technique for the measurement of atmospheric HONO and HNO3 is reported. The technique is based on aqueous scrubbing using two coil samplers, followed by conversion of HNO3 to nitrite, derivatization of nitrite to a highly light-absorbing azo dye with sulfanilamide (SA) and N-(1-naphthyl) ethylenediamine (NED), and high performance liquid chromatography (HPLC) analysis. HNO3 concentration was obtained by the difference of the two channels. Two scrubbing solutions were used for sampling the two species: a 1-mM phosphate buffer solution (pH 7) for the measurement of HONO and a 180 mM NH4Cl/NH3 buffer solution (pH 8.5) for the measurement of HONO+HNO3. The scrubbing solution flow rate was 0.24 ml min?1 and the gas sampling flow rate was 2 l min?1. HNO3 in the NH4Cl/NH3 buffer solution was quantitatively reduced to nitrite along an on-line 0.8-cm Cd reductor column. Nitrite in both channels was derivatized with 2 mM SA and 0.2 mM NED in 25 mM HCl. Quantitative derivatization was achieved within 5 min at 55°C. The azo dye derivative was then separated from the SA/NED reagent by reversed-phase HPLC and detected with a UV-vis detector at 540 nm. With an on-line SEP-PAK C-18 cartridge for the reagent purification, the method detection limit is estimated to be better than 1 pptv for HONO and about 20 pptv for HNO3. The sample integration time was about 2 min and the sampling frequency is every 10 min. Data collected in downtown Albany and Whiteface Mountain, NY, are shown as examples of applications of this technique in both urban and remote clean environments. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
