In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX

Martı́n, Juan Carlos Gómez; Blahins, J.; Gross, Uldis; Ingham, T.; Goddard, A.; Mahajan, Anoop S.; Ūbelis, Arnolds; Saiz‐Lopez, Alfonso

doi:10.5194/amt-4-29-2011

Cited by 14 publications

(11 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Upper limits for the rate constants of possible HOIO 2 -forming reactions can be obtained from kinetic modeling of our BBP experiments, and are discussed below. Separate flow tube measurements of atomic iodine by resonance fluorescence (ROFLEX) 35 were performed to study the removal of I atoms in the presence of MBL-representative concentrations of O 3 and H 2 O at 760 Torr. A slight enhancement of the I atom removal by O 3 in the presence of water was observed ( Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Additional experiments to study the influence of water on the removal of atomic iodine were carried out with the Resonance and off-Resonance Fluorescence by Lamp Excitation (ROFLEX) machine 35 in an atmospheric pressure BBP flow tube set up. A 3–15 slm flow of synthetic air carrying molecular iodine (~10 10 molecule cm −3 ) and ozone (~10 12 molecule cm −3 ) was passed to a 4-cm-diameter, 50-cm-long quartz tube where it was irradiated by a Xe arc lamp.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A gas-to-particle conversion mechanism helps to explain atmospheric particle formation through clustering of iodine oxides

et al. 2020

View full text Add to dashboard Cite

Emitted from the oceans, iodine-bearing molecules are ubiquitous in the atmosphere and a source of new atmospheric aerosol particles of potentially global significance. However, its inclusion in atmospheric models is hindered by a lack of understanding of the first steps of the photochemical gas-to-particle conversion mechanism. Our laboratory results show that under a high humidity and low HOx regime, the recently proposed nucleating molecule (iodic acid, HOIO2) does not form rapidly enough, and gas-to-particle conversion proceeds by clustering of iodine oxides (IxOy), albeit at slower rates than under dryer conditions. Moreover, we show experimentally that gas-phase HOIO2 is not necessary for the formation of HOIO2-containing particles. These insights help to explain new particle formation in the relatively dry polar regions and, more generally, provide for the first time a thermochemically feasible molecular mechanism from ocean iodine emissions to atmospheric particles that is currently missing in model calculations of aerosol radiative forcing.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

A gas-to-particle conversion mechanism helps to explain atmospheric particle formation through clustering of iodine oxides

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Measurements of atomic iodine were performed in October 2010 and February 2011 using the resonance and off‐resonance fluorescence by lamp excitation (ROFLEX) resonance fluorescence instrument [ Gómez Martín et al ., ]. Briefly, ambient air is pumped at a rate of ~7000 cm 3 min −1 through a low‐pressure chamber where the iodine atoms contained in the sample are excited by VUV radiation emitted by a radiofrequency discharge iodine lamp.…”

Section: Methodsmentioning

confidence: 99%

Iodine chemistry in the eastern Pacific marine boundary layer

et al. 2013

View full text Add to dashboard Cite

[1] Observations of gas-phase iodine species were made during a field campaign in the eastern Pacific marine boundary layer (MBL). The Climate and Halogen Reactivity Tropical Experiment (CHARLEX) in the Galápagos Islands, running from September 2010 to present, is the first long-term ground-based study of trace gases in this region. Observations of gas-phase iodine species were made using long-path differential optical absorption spectroscopy (LP-DOAS), multi-axis DOAS (MAX-DOAS), and resonance and off-resonance fluorescence by lamp excitation (ROFLEX). These measurements were supported by ancillary measurements of ozone, nitrogen oxides, and meteorological variables. Selective halocarbon and ultrafine aerosol concentration measurements were also made. MAX-DOAS observations of iodine monoxide (IO) display a weak seasonal variation. The maximum differential slant column density was 3.8 Â 10 13 molecule cm À2 (detection limit~7 Â 10 12 molecule cm À2 ). The seasonal variation of reactive iodine IO x (= I + IO) is stronger, peaking at 1.6 pptv during the warm season (February-April). This suggests a dependence of the iodine sources on the annual cycle in sea surface temperature, although perturbations by changes in ocean surface iodide concentration and solar radiation are also possible. An observed negative correlation of IO x with chlorophyll-a indicates a predominance of abiotic sources. The low IO mixing ratios measured (below the LP-DOAS detection limit of 0.9 pptv) are not consistent with satellite observations if IO is confined to the MBL. The IO x loading is consistent with the observed absence of strong ozone depletion and nucleation events, indicating a small impact of iodine chemistry on these climatically relevant factors in the eastern Pacific MBL.

show abstract

“…However, this has been a long-standing challenge due to their low abundance and short atmospheric lifetimes. Previous studies have achieved detection of relatively more abundant molecular iodine (I2), iodine monoxide (IO), and iodine dioxide (OIO) via optical spectroscopy, such as differential optical absorption (Leigh et al, 2010), cavity ring-down (Bitter et al, 2005), cavity enhanced absorption (Vaughan et al, 2008), laser-induced fluorescence (Dillon et al, 2006), and resonance fluorescence (Gómez Martín et al, 2011). The spectroscopic techniques are invaluable; however, their very specificity limits them to the detection of a few iodine compounds, and they are less sensitive to other iodine species that have congested or broad absorption cross sections such as hypoiodous acid (HOI) and iodic acid (HIO3).…”

Section: Introductionmentioning

confidence: 99%

Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers

Wang¹,

He²,

Finkenzeller³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of bromide chemical ionization mass spectrometers (Br-CIMS) to this task. During iodine new-particle formation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and inter-comparisons with other instruments attached to the CLOUD chamber, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtain detection limits of 5.8 × 106, 6.3 × 105, and 2.0 × 105 molec cm−3, respectively, for a 2-min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec cm−3, based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around one order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec cm−3, respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.

show abstract

In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX

Cited by 14 publications

References 70 publications

A gas-to-particle conversion mechanism helps to explain atmospheric particle formation through clustering of iodine oxides

A gas-to-particle conversion mechanism helps to explain atmospheric particle formation through clustering of iodine oxides

Iodine chemistry in the eastern Pacific marine boundary layer

Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers

Contact Info

Product

Resources

About