scholarly journals Bromine speciation in volcanic plumes: new in situ derivatization LC-MS method for the determination of gaseous hydrogen bromide by gas diffusion denuder sampling

2021 ◽  
Vol 14 (10) ◽  
pp. 6395-6406
Author(s):  
Alexandra Gutmann ◽  
Nicole Bobrowski ◽  
Marcello Liotta ◽  
Thorsten Hoffmann
Keyword(s):  
Collection Efficiency ◽  
Hydrogen Bromide ◽  
Chemical Characterization ◽  
Gas Diffusion ◽  
Gaseous Hydrogen ◽  
Ionization Mass ◽  
Volcanic Gas ◽  
Relative Standard ◽  
In Situ Derivatization

Abstract. The chemical characterization of volcanic gas emissions gives insights into the interior of volcanoes. Bromine species have been correlated with changes in the activity of a volcano. In order to exploit the volcanic bromine gases, we need to understand what happens to them after they are outgassed into the atmosphere. This study aims to shed light on the conversion of bromospecies after degassing. The method presented here allows for the specific analysis of gaseous hydrogen bromide (HBr) in volcanic environments. HBr is immobilized by reaction with 5,6-epoxy-5,6-dihydro-[1,10]-phenanthroline (EP), which acts as an inner coating inside of diffusion denuder tubes (in situ derivatization). The derivative is analyzed by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS). The collection efficiency for HBr (99.5 %), the collection efficiency for HBr alongside HCl (98.1 %), and the relative standard deviation of comparable samples (8 %) have been investigated. The comparison of the new denuder-based method and Raschig tubes as alkaline traps resulted on average in a relative bias between both methods of 10 ± 6 %. The denuder sampling setup was applied in the plume of Masaya (Nicaragua) in 2016. HBr concentrations in the range between 0.44 and 1.97 ppb were measured with limits of detection and quantification below 0.1 and 0.3 ppb respectively. The relative contribution of HBr as a fraction of total bromine decreased from 75 ± 11 % at the Santiago crater (214 m distance to the volcanic emission source) to 36 ± 8 % on the Nindiri rim (740 m distance). A comparison between our data and the previously calculated HBr, based on the CAABA/MECCA box model, showed a slightly higher trend for the HBr fraction on average than expected from the model. Data gained from this new method can further refine model runs in the future.

scholarly journals Bromine Speciation in Volcanic Plumes: New in-situ Derivatization LC-MS Method for the Determination of Gaseous Hydrogen Bromide by Gas Diffusion Denuder Sampling

2020 ◽  
Author(s):  
Alexandra Gutmann ◽  
Nicole Bobrowski ◽  
Marcello Liotta ◽  
Thorsten Hoffmann
Keyword(s):  
Matrix Effects ◽  
Hydrogen Bromide ◽  
Gas Diffusion ◽  
Gaseous Hydrogen ◽  
Ionization Mass ◽  
Volcanic Plumes ◽  
Analytical Approaches ◽  
In Situ Derivatization

Abstract. The chemical characterization of volcanic gas emissions gives insights into the interior of volcanoes. Monitoring of BrO/SO2-ratios has recently been correlated with changes in the activity of a volcano. BrO and SO2 can both be measured autonomously and simultaneously with the same instruments from a safe distance, making their ratio potentially a strong monitoring tool. However, BrO is not a primary emitted volcanic volatile and there exist still uncertainties about the formation of BrO in volcanic plumes, mostly due to the lack of analytical approaches for the accurate speciation of certain key compounds. This study describes a new method for the determination of the BrO precursor, the gaseous hydrogen bromide (HBr), by quantitative collection in denuder samplers. Gas diffusion denuders use the difference in diffusion coefficients to separate gaseous from particle-phase compounds. Gaseous HBr molecules are immobilized with an organic coating at the inner walls of the denuder tubes when pumped through the denuders. Five different coatings using 1,2-epoxycyclooctane, trans-oxirane-2,3-dicarboxylic acid, 2,3-epoxy-3-phenylpropanoic acid, 9,10-epoxystearic acid, 5,6-epoxy-5,6-dihydro-[1,10]-phenanthroline (EP) were tested as denuder coatings. EP proved to be a suitable coating reagent, which at the same time, transfers the analyte into an appropriate derivate to be analyzed by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (in situ derivatization). Coating amount, breakthrough, matrix effects and the storage behavior have been characterized. No considerable cross-sensitivity with hydrogen chloride or other bromine species such as molecular bromine was observed. The comparison of HBr determination using EP-coated denuders and Raschig Tubes as alkaline traps in the laboratory showed a deviation of 2 ± 11 % for gaseous HBr between the two methods. This allows considering HBr determined by denuders as a fraction of total bromine determined by Raschig Tubes. Since other bromine species (e.g. elemental bromine, bromine oxides) are also collected and determined as bromide by Raschig Tubes, but exclusively HBr in EP-coated denuders, the method presented here allows more accurate speciation of gaseous bromine compounds and their application in volcanic plumes. The denuder sampling setup was applied with complementary denuder systems and alkaline traps in the plume of Masaya (Nicaragua) in 2016. HBr concentrations in the range between 0.44 and 2.27 ppb were measured with limits of detection and quantification below 0.1 and 0.3 ppb respectively at typical ground-based sampling conditions. The relative contribution of HBr as a fraction of total bromine decreased from 75 ± 11 % at Santiago rim (214 m distance to the volcanic emission source) to 36 ± 8 % on Nindiri rim (740 m distance). Our findings are in good agreement with previous estimations of the HBr conversion from the chemistry box model (CAABA/MECCA).

scholarly journals Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

2012 ◽  
Vol 12 (3) ◽  
pp. 1327-1338 ◽  
Author(s):  
J. Liao ◽  
L. G. Huey ◽  
E. Scheuer ◽  
J. E. Dibb ◽  
R. E. Stickel ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Hydrogen Bromide ◽  
The Arctic ◽  
Ionization Mass ◽  
Atmospheric Conditions ◽  
Vertical Column ◽  
Bromine Oxide ◽  
Mixing Ratios ◽  
Mist Chamber

Abstract. A focus of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was examination of bromine photochemistry in the spring time high latitude troposphere based on aircraft and satellite measurements of bromine oxide (BrO) and related species. The NASA DC-8 aircraft utilized a chemical ionization mass spectrometer (CIMS) to measure BrO and a mist chamber (MC) to measure soluble bromide. We have determined that the MC detection efficiency to molecular bromine (Br2), hypobromous acid (HOBr), bromine oxide (BrO), and hydrogen bromide (HBr) as soluble bromide (Br−) was 0.9±0.1, 1.06+0.30/−0.35, 0.4±0.1, and 0.95±0.1, respectively. These efficiency factors were used to estimate soluble bromide levels along the DC-8 flight track of 17 April 2008 from photochemical calculations constrained to in situ BrO measured by CIMS. During this flight, the highest levels of soluble bromide and BrO were observed and atmospheric conditions were ideal for the space-borne observation of BrO. The good agreement (R2 = 0.76; slope = 0.95; intercept = −3.4 pmol mol−1) between modeled and observed soluble bromide, when BrO was above detection limit (>2 pmol mol−1) under unpolluted conditions (NO<10 pmol mol−1), indicates that the CIMS BrO measurements were consistent with the MC soluble bromide and that a well characterized MC can be used to derive mixing ratios of some reactive bromine compounds. Tropospheric BrO vertical column densities (BrOVCD) derived from CIMS BrO observations compare well with BrOTROPVCD from OMI on 17 April 2008.

scholarly journals Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

2011 ◽  
Vol 11 (9) ◽  
pp. 26999-27030 ◽  
Author(s):  
J. Liao ◽  
L. G. Huey ◽  
E. Scheuer ◽  
J. E. Dibb ◽  
R. E. Stickel ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Hydrogen Bromide ◽  
The Arctic ◽  
Ionization Mass ◽  
Atmospheric Conditions ◽  
Vertical Column ◽  
Bromine Oxide ◽  
Mist Chamber

Abstract. A focus of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was examination of bromine photochemistry in the spring time, high latitude troposphere based on aircraft and satellite measurements of BrO and related species. The NASA DC-8 aircraft utilized a chemical ionization mass spectrometry (CIMS) instrument to measure BrO and a mist chamber (MC) to measure soluble bromide. We have determined that the MC detection efficiency to molecular bromine (Br2), hypobromous acid (HOBr), bromine oxide (BrO), and hydrogen bromide (HBr) as soluble bromide (Br−) was 0.9±0.1, 1.06±0.30, 0.4±0.1, and 0.95±0.1, respectively. These efficiency factors were used to estimate soluble bromide levels along the DC-8 flight track of 17 April 2008 from photochemical calculations constrained to in situ BrO measured by CIMS. During this flight, the highest levels of soluble bromide and BrO were observed and atmospheric conditions were ideal for the space-borne observation of BrO. The good agreement (R2 = 0.76; slope = 0.98; intercept = −3.5 pptv) between modeled and observed soluble bromide, when BrO was above detection limit (>2 pptv) under unpolluted conditions (NO < 100 pptv), indicates that the CIMS BrO measurements were consistent with the MC soluble bromide. Tropospheric BrO vertical column densities (BROTROPVCD) derived from CIMS BrO observations compare well with BROTROPVCD from OMI on 17 April 2008.

scholarly journals Electrokinetic and in situ spectroscopic investigations of CO electrochemical reduction on copper

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Li ◽  
Xiaoxia Chang ◽  
Haochen Zhang ◽  
Arnav S. Malkani ◽  
Mu-jeng Cheng ◽  
...  
Keyword(s):  
Mass Transport ◽  
Active Sites ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Diffusion Type ◽  
Proton Coupled Electron Transfer ◽  
Alkaline Electrolytes ◽  
Reaction Orders

AbstractRigorous electrokinetic results are key to understanding the reaction mechanisms in the electrochemical CO reduction reaction (CORR), however, most reported results are compromised by the CO mass transport limitation. In this work, we determined mass transport-free CORR kinetics by employing a gas-diffusion type electrode and identified dependence of catalyst surface speciation on the electrolyte pH using in-situ surface enhanced vibrational spectroscopies. Based on the measured Tafel slopes and reaction orders, we demonstrate that the formation rates of C2+ products are most likely limited by the dimerization of CO adsorbate. CH4 production is limited by the CO hydrogenation step via a proton coupled electron transfer and a chemical hydrogenation step of CO by adsorbed hydrogen atom in weakly (7 < pH < 11) and strongly (pH > 11) alkaline electrolytes, respectively. Further, CH4 and C2+ products are likely formed on distinct types of active sites.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

Ice-Phase Precipitation

2017 ◽  
Vol 58 ◽  
pp. 6.1-6.36 ◽  
Author(s):  
I. Gultepe ◽  
A. J. Heymsfield ◽  
P. R. Field ◽  
D. Axisa
Keyword(s):  
Collection Efficiency ◽  
Numerical Models ◽  
Mass Density ◽  
Three Dimensional ◽  
Phase Precipitation ◽  
Microphysical Parameters ◽  
Mass Size ◽  
Ice Water ◽  
Ice Phase

AbstractIce-phase precipitation occurs at Earth’s surface and may include various types of pristine crystals, rimed crystals, freezing droplets, secondary crystals, aggregates, graupel, hail, or combinations of any of these. Formation of ice-phase precipitation is directly related to environmental and cloud meteorological parameters that include available moisture, temperature, and three-dimensional wind speed and turbulence, as well as processes related to nucleation, cooling rate, and microphysics. Cloud microphysical parameters in the numerical models are resolved based on various processes such as nucleation, mixing, collision and coalescence, accretion, riming, secondary ice particle generation, turbulence, and cooling processes. These processes are usually parameterized based on assumed particle size distributions and ice crystal microphysical parameters such as mass, size, and number and mass density. Microphysical algorithms in the numerical models are developed based on their need for applications. Observations of ice-phase precipitation are performed using in situ and remote sensing platforms, including radars and satellite-based systems. Because of the low density of snow particles with small ice water content, their measurements and predictions at the surface can include large uncertainties. Wind and turbulence affecting collection efficiency of the sensors, calibration issues, and sensitivity of ground-based in situ observations of snow are important challenges to assessing the snow precipitation. This chapter’s goals are to provide an overview for accurately measuring and predicting ice-phase precipitation. The processes within and below cloud that affect falling snow, as well as the known sources of error that affect understanding and prediction of these processes, are discussed.

scholarly journals Soil physico-chemical characterization in the different soil layers of National Maize Research Program, Rampur, Chitwan, Nepal

2018 ◽  
Vol 3 (1) ◽  
pp. 28-44
Author(s):  
Dinesh Khadka ◽  
Sushil Lamichhane ◽  
Amit P Timilsina ◽  
Bandhu R Baral ◽  
Kamal Sah ◽  
...  
Keyword(s):  
Research Program ◽  
Soil Structure ◽  
Sandy Loam ◽  
Chemical Properties ◽  
Single Layer ◽  
Chemical Characterization ◽  
Bottom Layer ◽  
Soil Parameters ◽  
Physico Chemical

Soil pit digging and their precise study is a decision making tool to assess history and future of soil management of a particular area. Thus, the present study was carried out to differentiate soil physico-chemical properties in the different layers of excavated pit of the National Maize Research Program, Rampur, Chitwan, Nepal. Eight pits were dug randomly from three blocks at a depth of 0 to 100 cm. The soil parameters were determined in-situ, and in laboratory for texture, pH, OM, N, P (as P2O5), K (as K2O), Ca, Mg, S, B, Fe, Zn, Cu and Mn of collected soils samples of different layers following standard analytical methods at Soil Science Division, Khumaltar. The result revealed that soil structure was sub-angular in majority of the layers, whereas bottom layer was single grained. The value and chrome of colour was increasing in order from surface to bottom in the majority pits. Similarly, the texture was sandy loam in majority layers of the pits. Moreover, four types of consistence (loose to firm) were observed. Furthermore, mottles and gravels were absent in the majority layers. Likewise, soil was very to moderately acidic in observed layers of majority pits, except bottom layer of agronomy block was slightly acidic. Regarding fertility parameters (OM, macro and micronutrients), some were increasing and vice-versa, while others were intermittent also. Therefore, a single layer is not dominant for particular soil physico-chemical parameters in the farm. In overall, surface layer is more fertile than rest of the layers in all the pits.     

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