A novel spectroscopic approach for detection of chlorine reservoir species: HCl-TILDAS

2020 ◽  
Author(s):  
John Halfacre ◽  
Pete Edwards ◽  
Scott Herndon ◽  
Joseph Roscioli ◽  
Christoph Dyroff ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chlorine Atom ◽  
Nitrogen Loss ◽  
Tunable Laser ◽  
Ozone Production ◽  
Specific Method ◽  
Nitryl Chloride ◽  
Reservoir Species ◽  
Chlorine Radicals ◽  
Observational Techniques

<p>Atomic chlorine radicals are known to affect atmospheric oxidation and pollutant lifetimes, but are challenging to detect due to their low ambient concentrations.  A lack of field observations limits useful assessments of the impacts of tropospheric chlorine oxidation on important atmospheric processes, such as regional ozone production, reactive nitrogen loss, and global methane removal.  In the last decade, instrumental innovations have enabled detection and speciation of much more stable chlorine atom reservoir species, such as nitryl chloride, through techniques such as cavity ring down spectroscopy and mass spectrometry.  HCl is the most abundant and long-lived tropospheric chlorine reservoir species, yet few observations exist.  Here, we present a specific method for detection of HCl via Tunable Laser Infrared Direct Absorption Spectrometer (TILDAS), which has been further extended for the detection of nitryl chloride.  This analytical method has several advantages over current observational techniques (e.g. chemical ionisation mass spectrometry), and will provide a much needed constraint on the tropospheric chlorine atom budget.</p>

Ubiquity of ClNO2 in the urban boundary layer of Calgary, Alberta, Canada

2016 ◽  
Vol 94 (4) ◽  
pp. 414-423 ◽  
Author(s):  
Levi H. Mielke ◽  
Amanda Furgeson ◽  
Charles A. Odame-Ankrah ◽  
Hans D. Osthoff
Keyword(s):  
Chlorine Atom ◽  
Urban Environments ◽  
Heterogeneous Reactions ◽  
Ionization Mass ◽  
Mixing Ratios ◽  
Nitryl Chloride ◽  
Reservoir Species ◽  
Intermittent Measurements ◽  
Oxidation Of No

The role of nitryl chloride (ClNO2) as a nocturnal nitrogen oxide reservoir species and chlorine atom precursor is well established for polluted coastal areas, but its role at midcontinental locations is less clear. In this paper, intermittent measurements over the course of several seasons of ClNO2 mixing ratios by iodide ion chemical ionization mass spectrometry in Calgary, Alberta, Canada, are presented. Mixing ratios were highly variable between nights and seasons and depended on the abundances of precursors and meteorological conditions. The lowest ClNO2 mixing ratios (nocturnal maximum of 30 parts per trillion by volume (pptv)) were observed in the summer, rationalized by losses of the nitrate radical (NO3) that were more efficient than in the other months. Higher ClNO2 mixing ratios (up to 330 pptv) were observed in the winter and spring months but varied between nights. In the fall, ClNO2 mixing ratios increased from night to night following the application of salt to roads. The ClNO2 yield relative to the amount of NO3 produced from oxidation of NO2 by O3 ranged from 0.1% to 4.5% (10th and 90th percentiles, median 1.0%). The ClNO2 yield relative to N2O5 consumed by heterogeneous reactions was estimated using a time-integrated box model and ranged from 0.5% to 12.1% (10th and 90th percentiles, median 3.4%). The ubiquity of ClNO2 implies that the chlorine atom needs to be considered as an oxidant in high-latitude urban environments in winter.

scholarly journals Regional and intercontinental pollution signatures on modeled and measured PAN at northern mid-latitude mountain sites

2018 ◽  
Author(s):  
Arlene M. Fiore ◽  
Emily V. Fischer ◽  
Shubha Pandey Deolal ◽  
Oliver Wild ◽  
Dan Jaffe ◽  
...  
Keyword(s):  
Transport Model ◽  
Ozone Production ◽  
Anthropogenic Emissions ◽  
Chemical Transport Model ◽  
Reservoir Species ◽  
Remote Troposphere ◽  
Global Chemical Transport Model ◽  
Peroxy Acetyl Nitrate ◽  
Source Receptor Relationships

Abstract. Peroxy acetyl nitrate (PAN) is the most important reservoir species for nitrogen oxides (NOx) in the remote troposphere. Upon decomposition in remote regions, PAN promotes efficient ozone production. We evaluate monthly mean PAN abundances from global chemical transport model simulations (HTAP1) for 2001 with measurements from five northern mid-latitude mountain sites (four European and one North American). The multi-model mean generally captures the observed monthly mean PAN but individual models simulate a factor of ~ 4–8 range in monthly abundances. We quantify PAN source-receptor relationships at the measurement sites with sensitivity simulations that decrease regional anthropogenic emissions of PAN (and ozone) precursors by 20 % from North America (NA), Europe (EU), and East Asia (EA). The HTAP1 models attribute more of the observed PAN at Jungfraujoch (Switzerland) to emissions in NA and EA, and less to EU, than a prior trajectory-based estimate. The trajectory-based and modeling approaches agree that EU emissions play a role in the observed springtime PAN maximum at Jungfraujoch. The signal from anthropogenic emissions on PAN is strongest at Jungfraujoch and Mount Bachelor (Oregon, U.S.A.) during April. In this month, PAN source-receptor relationships correlate both with model differences in regional anthropogenic volatile organic compound (AVOC) emissions and with ozone source-receptor relationships. PAN observations at mountaintop sites can thus provide key information for evaluating models, including links between PAN and ozone production and source-receptor relationships. Establishing routine, long-term, mountaintop measurements is essential given the large observed interannual variability in PAN.

scholarly journals Urban inland wintertime N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> influenced by snow-covered ground, air turbulence, and precipitation

2021 ◽  
Author(s):  
Kathryn D. Kulju ◽  
Stephen M. McNamara ◽  
Qianjie Chen ◽  
Jacinta Edebeli ◽  
Jose D. Fuentes ◽  
...  
Keyword(s):  
Ground Cover ◽  
Atmospheric Particulate Matter ◽  
Ionization Mass ◽  
Bare Ground ◽  
Near Surface ◽  
Dinitrogen Pentoxide ◽  
Nitryl Chloride ◽  
Air Turbulence ◽  
Chlorine Radicals ◽  
Wet Scavenging

Abstract. The atmospheric multiphase reaction of dinitrogen pentoxide (N2O5) with chloride-containing aerosol particles produces nitryl chloride (ClNO2), which has been observed across the globe. The photolysis of ClNO2 produces chlorine radicals and nitrogen dioxide (NO2), which alter pollutant fates and air quality. However, the effects of local meteorology on near-surface ClNO2 production are not yet well understood, as most observational and modeling studies focus on periods of clear conditions. During a field campaign in Kalamazoo, Michigan from January–February 2018, N2O5 and ClNO2 were measured using chemical ionization mass spectrometry, with simultaneous measurements of atmospheric particulate matter and meteorological parameters. We examine the impacts of atmospheric turbulence, precipitation (snow, rain) and fog, and ground cover (snow-covered and bare ground) on the abundances of ClNO2 and N2O5. N2O5 mole ratios were lowest during periods of lower turbulence and were not statistically significantly different between snow-covered and bare ground. In contrast, ClNO2 mole ratios were highest, on average, over snow-covered ground, due to saline snowpack ClNO2 production. Both N2O5 and ClNO2 mole ratios were lowest, on average, during rainfall and fog because of scavenging, with N2O5 scavenging by fog droplets likely contributing to observed increased particulate nitrate concentrations. These observations, specifically those during active precipitation and with snow-covered ground, highlight important processes, including N2O5 and ClNO2 wet scavenging, fog nitrate production, and snowpack ClNO2 production, that govern the variability in observed atmospheric chlorine and nitrogen chemistry and are missed when considering only clear conditions.

scholarly journals Integration of Airborne and Ground Observations of Nitryl Chloride in the Seoul Metropolitan Area and the Implications on Regional Oxidation Capacity During KORUS-AQ 2016

2018 ◽  
Author(s):  
Daun Jeong ◽  
Roger Seco ◽  
Dasa Gu ◽  
Youngro Lee ◽  
Benjamin A. Nault ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Box Model ◽  
Ozone Production ◽  
Integrated Analysis ◽  
Back Trajectory ◽  
Night Time ◽  
Model Calculations ◽  
Nitryl Chloride ◽  
Seoul Metropolitan Area ◽  
The Impact

Abstract. Nitryl chloride (ClNO2) is a radical reservoir species that releases chlorine radicals upon photolysis. An integrated analysis of the impact of ClNO2 on regional photochemistry in the Seoul Metropolitan Area (SMA) during the Korean-United States-Air Quality (KORUS-AQ) 2016 field campaign is presented. Comprehensive multiplatform observations were conducted aboard the NASA DC-8 and at two ground sites (Olympic Park, OP; Taehwa Research Forest, TRF), representing an urbanized area and a forested region downwind, respectively. The overall diurnal variations of ClNO2 in both sites appeared similar but the night time variation were systematically different. For about half of the observation days at the OP site the level of ClNO2 increased at sunset but rapidly decreased at around midnight. On the other hand, high levels were sustained throughout the night at the TRF site. Significant levels of ClNO2 were sustained at both sites for 4–5 hours after sunrise. Airborne observations, box model calculations, and back trajectory analysis consistently show that this high levels of ClNO2 in the morning is likely due to the transport of air masses within the boundary layer. Box model results show that chlorine radical initiated chemistry can impact the regional photochemistry by elevating net ozone production rate up to ~ 25 % in the morning.

scholarly journals Development and validation of sensitive method for determination of serum cotinine in smokers and nonsmokers by liquid chromatography/atmospheric pressure ionization tandem mass spectrometry

1997 ◽  
Vol 43 (12) ◽  
pp. 2281-2291 ◽  
Author(s):  
John T Bernert ◽  
Wayman E Turner ◽  
James L Pirkle ◽  
Connie S Sosnoff ◽  
James R Akins ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atmospheric Pressure ◽  
High Resolution Mass Spectrometry ◽  
Limit Of Detection ◽  
Atmospheric Pressure Chemical Ionization ◽  
Current Method ◽  
Specific Method ◽  
Tandem Mass ◽  
Serum Samples ◽  
Serum Cotinine

Abstract We describe a sensitive and specific method for measuring cotinine in serum by HPLC coupled to an atmospheric pressure chemical ionization tandem mass spectrometer. This method can analyze 100 samples/day on a routine basis, and its limit of detection of 50 ng/L makes it applicable to the analysis of samples from nonsmokers potentially exposed to environmental tobacco smoke. Analytical accuracy has been demonstrated from the analysis of NIST cotinine standards and from comparative analyses by both the current method and gas chromatography/high-resolution mass spectrometry. Precision has been examined through the repetitive analysis of a series of bench and blind QC materials. This method has been applied to the analysis of cotinine in serum samples collected as part of the Third National Health and Nutrition Examination Survey (NHANES III).

scholarly journals Rapid Screening of High-Risk Patients for Disorders of Purine and Pyrimidine Metabolism Using HPLC-Electrospray Tandem Mass Spectrometry of Liquid Urine or Urine-soaked Filter Paper Strips

2000 ◽  
Vol 46 (4) ◽  
pp. 445-452 ◽  
Author(s):  
Tetsuya Ito ◽  
André B P van Kuilenburg ◽  
Albert H Bootsma ◽  
Anja J Haasnoot ◽  
Arno van Cruchten ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Filter Paper ◽  
Screening Method ◽  
Urine Samples ◽  
Rapid Screening ◽  
Specific Method ◽  
Tandem Mass ◽  
Pyrimidine Metabolism ◽  
Inherited Disorders

Abstract Background: A rapid and specific screening method for patients at risk of inherited disorders of purine and pyrimidine metabolism is desirable because symptoms are varied and nonspecific. The aim of this study was to develop a rapid and specific method for screening with use of liquid urine samples or urine-soaked filter paper strips. Methods: Reverse-phase HPLC was combined with electrospray ionization (ESI), tandem mass spectrometry (MS/MS), and detection performed by multiple reaction monitoring. Transitions and instrument settings were established for 17 purines or pyrimidines. Stable-isotope-labeled reference compounds were used as internal standards when available. Results: Total analysis time of this method was 15 min, approximately one-third that of conventional HPLC with ultraviolet detection. Recoveries were 96–107% in urine with added analyte, with two exceptions (hypoxanthine, 64%; xanthine, 79%), and 89–110% in urine-soaked filter paper strips, with three exceptions (hypoxanthine, 65%; xanthine, 77%; 5-hydroxymethyluracil, 80%). The expected abnormalities were easily found in samples from patients with purine nucleoside phosphorylase deficiency, ornithine transcarbamylase deficiency, molybdenum cofactor deficiency, adenylosuccinase deficiency, or dihydropyrimidine dehydrogenase deficiency. Conclusions: HPLC-ESI MS/MS of urine allows rapid screening for disorders of purine and pyrimidine metabolism. The filter paper strips offer the advantage of easy collection, transport, and storage of the urine samples.

Estradiol-17 beta determined in plasma by gas chromatography-mass spectrometry with selected ion monitoring of mixed silyl ether-perfluoroacyl ester derivatives and use of various stable-isotope-labeled internal standards.

1989 ◽  
Vol 35 (4) ◽  
pp. 532-536 ◽  
Author(s):  
L Dehennin
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Stable Isotope ◽  
Trimethylsilyl Ether ◽  
Gas Chromatography Mass Spectrometry ◽  
Specific Method ◽  
Silyl Ether ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Target Values

Abstract A highly specific method is described for measuring estradiol-17 beta (E2) in plasma by gas chromatography-mass spectrometry (GC-MS) associated with stable isotope dilution. A mixed derivative, E2-3-trimethylsilyl ether-17-heptafluorobutyrate (E2-3-TMS-17-HFB), was found to have excellent analytical properties. The specificity of the derivatization procedure exploits a unique feature of estrogens: the selective exchange of a phenolic perfluoroacyl ester for a trialkylsilyl ether. No significant differences in E2 concentration could be ascribed to the use of 2H- or 13C-labeled analogs, thus ruling out interferences from possible isotope exchange commonly attributed to deuterated compounds. Precision is closely similar to that for methods in which the more common E2-3, 17-bis(trimethylsilyl) ether and E2-3, 17-bis(heptafluorobutyrate) derivatives are used. Sensitivity and specificity of the mixed 3-TMS-17-HFB derivative allow adequate determinations of E2, even in plasma from males, in 2-mL samples. Interlaboratory mean concentrations of E2 obtained by routine immunoassays were consistently higher than the target values estimated by GC-MS, particularly at concentrations less than 100 pmol/L.

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