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Gorkowski K, Donahue NM, Sullivan RC. Aerosol Optical Tweezers Constrain the Morphology Evolution of Liquid-Liquid Phase-Separated Atmospheric Particles. Chem 2020. [DOI: 10.1016/j.chempr.2019.10.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Enhancing Double-Beam Laser Tweezers Raman Spectroscopy (LTRS) for the Photochemical Study of Individual Airborne Microdroplets. Molecules 2019; 24:molecules24183325. [PMID: 31547361 PMCID: PMC6766935 DOI: 10.3390/molecules24183325] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/03/2019] [Accepted: 09/05/2019] [Indexed: 11/23/2022] Open
Abstract
A new device and methodology for vertically coupling confocal Raman microscopy with optical tweezers for the in situ physico- and photochemical studies of individual microdroplets (Ø ≤ 10 µm) levitated in air is presented. The coupling expands the spectrum of studies performed with individual particles using laser tweezers Raman spectroscopy (LTRS) to photochemical processes and spatially resolved Raman microspectroscopy on airborne aerosols. This is the first study to demonstrate photochemical studies and Raman mapping on optically levitated droplets. By using this configuration, photochemical reactions in aerosols of atmospheric interest can be studied on a laboratory scale under realistic conditions of gas-phase composition and relative humidity. Likewise, the distribution of photoproducts within the drop can also be observed with this setup. The applicability of the coupling system was tested by studying the photochemical behavior of microdroplets (5 µm < Ø < 8 µm) containing an aqueous solution of sodium nitrate levitated in air and exposed to narrowed UV radiation (254 ± 25 nm). Photolysis of the levitated NaNO3 microdroplets presented photochemical kinetic differences in comparison with larger NaNO3 droplets (40 µm < Ø < 80 µm), previously photolyzed using acoustic traps, and heterogeneity in the distribution of the photoproducts within the drop.
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Selective Monitoring of Oxyanion Mixtures by a Flow System with Raman Detection. SENSORS 2018; 18:s18072196. [PMID: 29986534 PMCID: PMC6069446 DOI: 10.3390/s18072196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/29/2018] [Accepted: 07/06/2018] [Indexed: 11/17/2022]
Abstract
Raman spectroscopy is a selective detection system scarcely applied for the flow analysis of solutions with the aim of detecting several compounds at once without a previous separation step. This work explores the potential of a portable Raman system in a flow system for the selective detection of a mixture of seven oxyanions (carbonate, sulphate, nitrate, phosphate, chlorate, perchlorate, and thiosulphate). The specific bands of these compounds (symmetric stretching Raman active vibrations of carbonate at 1068 cm−1, nitrate at 1049 cm−1, thiosulphate at 998 cm−1, phosphate at 989 cm−1, sulphate at 982 cm−1, perchlorate at 935 cm−1, and chlorate at 932 cm−1) enabled their simultaneous detection in mixtures. Although the oxyanions’ limit of detection (LOD) was rather poor (in the millimolar range), this extremely simple system is very useful for the single-measurement detection of most of the oxyanions in mixtures, without requiring a previous separation step. In addition, quantitative determination of the desired oxyanion can be performed by means of the corresponding calibration line. These are important advantages for controlling in-line processes in industries like those manufacturing fertilizers, pharmaceuticals, chemicals, or food, among others.
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Gorkowski K, Donahue NM, Sullivan RC. Emulsified and Liquid-Liquid Phase-Separated States of α-Pinene Secondary Organic Aerosol Determined Using Aerosol Optical Tweezers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12154-12163. [PMID: 28985066 DOI: 10.1021/acs.est.7b03250] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate the first capture and analysis of secondary organic aerosol (SOA) on a droplet suspended in an aerosol optical tweezers (AOT). We examine three initial chemical systems of aqueous NaCl, aqueous glycerol, and squalane at ∼75% relative humidity. For each system we added α-pinene SOA-generated directly in the AOT chamber-to the trapped droplet. The resulting morphology was always observed to be a core of the original droplet phase surrounded by a shell of the added SOA. We also observed a stable emulsion of SOA particles when added to an aqueous NaCl core phase, in addition to the shell of SOA. The persistence of the emulsified SOA particles suspended in the aqueous core suggests that this metastable state may persist for a significant fraction of the aerosol lifecycle for mixed SOA/aqueous particle systems. We conclude that the α-pinene SOA shell creates no major diffusion limitations for water, glycerol, and squalane core phases under humid conditions. These experimental results support the current prompt-partitioning framework used to describe organic aerosol in most atmospheric chemical transport models and highlight the prominence of core-shell morphologies for SOA on a range of core chemical phases.
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Affiliation(s)
- Kyle Gorkowski
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Neil M Donahue
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Ryan C Sullivan
- Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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Haddrell AE, Miles REH, Bzdek BR, Reid JP, Hopkins RJ, Walker JS. Coalescence Sampling and Analysis of Aerosols using Aerosol Optical Tweezers. Anal Chem 2017; 89:2345-2352. [DOI: 10.1021/acs.analchem.6b03979] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Allen E. Haddrell
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - Bryan R. Bzdek
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Rebecca J. Hopkins
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Jim S. Walker
- Bristol Industrial and Research Associates Ltd (BIRAL), Unit 8 Harbour Road Trading Estate, Portishead, Bristol BS20 7BL, United Kingdom
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Hunt OR, Ward AD, King MD. Heterogeneous oxidation of nitrite anion by gas-phase ozone in an aqueous droplet levitated by laser tweezers (optical trap): is there any evidence for enhanced surface reaction? Phys Chem Chem Phys 2015; 17:2734-41. [DOI: 10.1039/c4cp05062b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Optical trapping of micron-sized droplet morphology and heterogeneous kinetics with gas-phase ozone with nitrite in a wall-less apparatus.
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Affiliation(s)
- Oliver R. Hunt
- Department of Earth Sciences
- Royal Holloway University of London
- Egham
- UK
- Central Laser Facility
| | - Andrew D. Ward
- Central Laser Facility
- Research Complex at Harwell
- Rutherford Appleton Laboratory
- Harwell Innovation Campus
- Didcot
| | - Martin D. King
- Department of Earth Sciences
- Royal Holloway University of London
- Egham
- UK
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Zhang QN, Zhang Y, Cai C, Guo YC, Reid JP, Zhang YH. In Situ Observation on the Dynamic Process of Evaporation and Crystallization of Sodium Nitrate Droplets on a ZnSe Substrate by FTIR-ATR. J Phys Chem A 2014; 118:2728-37. [DOI: 10.1021/jp412073c] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Qing-Nuan Zhang
- Institute
of Chemical Physics, Key Laboratory of Cluster Science, School of
Chemistry, Beijing Institute of Technology, Beijing 100081, China
| | - Yun Zhang
- Institute
of Chemical Physics, Key Laboratory of Cluster Science, School of
Chemistry, Beijing Institute of Technology, Beijing 100081, China
| | - Chen Cai
- Institute
of Chemical Physics, Key Laboratory of Cluster Science, School of
Chemistry, Beijing Institute of Technology, Beijing 100081, China
| | - Yu-Cong Guo
- Institute
of Chemical Physics, Key Laboratory of Cluster Science, School of
Chemistry, Beijing Institute of Technology, Beijing 100081, China
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS81TS, U.K
| | - Yun-Hong Zhang
- Institute
of Chemical Physics, Key Laboratory of Cluster Science, School of
Chemistry, Beijing Institute of Technology, Beijing 100081, China
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Power R, Reid JP, Anand S, McGloin D, Almohamedi A, Mistry NS, Hudson AJ. Observation of the Binary Coalescence and Equilibration of Micrometer-Sized Droplets of Aqueous Aerosol in a Single-Beam Gradient-Force Optical Trap. J Phys Chem A 2012; 116:8873-84. [DOI: 10.1021/jp304929t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- R. Power
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
| | - J. P. Reid
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
| | - S. Anand
- Electronic Engineering and Physics
Division, University of Dundee, Dundee,
DD1 4HN, United Kingdom
| | - D. McGloin
- Electronic Engineering and Physics
Division, University of Dundee, Dundee,
DD1 4HN, United Kingdom
| | - A. Almohamedi
- Department
of Physics, University of Leicester, Leicester,
LE1 7RH, United
Kingdom
| | - N. S. Mistry
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, United
Kingdom
| | - A. J. Hudson
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, United
Kingdom
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Mason BJ, King SJ, Miles REH, Manfred KM, Rickards AMJ, Kim J, Reid JP, Orr-Ewing AJ. Comparison of the Accuracy of Aerosol Refractive Index Measurements from Single Particle and Ensemble Techniques. J Phys Chem A 2012; 116:8547-56. [DOI: 10.1021/jp3049668] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bernard J. Mason
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Simon-John King
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Rachael E. H. Miles
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Katherine M. Manfred
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | | | - Jin Kim
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
| | - Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K
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OKAGBARE PAULI, MORRIS MICHAELD. Fluorocarbon fiber-optic Raman probe for non-invasive Raman spectroscopy. APPLIED SPECTROSCOPY 2012; 66:728-30. [PMID: 22732546 PMCID: PMC3384561 DOI: 10.1366/12-06592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report the development of a novel fiber-optic Raman probe using a graded index fluorocarbon optical fiber. The fluorocarbon fiber has a simple Raman spectrum, a low fluorescence background, and generates a Raman signal that in turbid media serves as an intense reference Raman signal that corrects for albedo. The intensity of the reference signal can easily be varied as needed by scaling the length of the excitation fiber. Additionally, the fluorocarbon probe eliminates the broad silica Raman bands generated in conventional silica-core fiber without the need for filters.
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12
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Krieger UK, Marcolli C, Reid JP. Exploring the complexity of aerosol particle properties and processes using single particle techniques. Chem Soc Rev 2012; 41:6631-62. [DOI: 10.1039/c2cs35082c] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Okagbare PI, Morris MD. Polymer-capped fiber-optic Raman probe for non-invasive Raman spectroscopy. Analyst 2011; 137:77-81. [PMID: 22059232 DOI: 10.1039/c1an15847c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advances in fiber optic probe design are moving Raman spectroscopy into the clinic, although there remain important practical problems. While much effort has been devoted to minimizing Raman and fluorescence background from fibers, less attention has been given to the need to generate reference Raman signals that can correct for variations in tissue albedo, which is important in quantifying changes in tissue composition. To address this shortcoming, we have developed a fiber optic probe that incorporates a fluorinated ethylene-propylene copolymer (FEP) cap at the end of each excitation fiber. Transmission of laser light through the transparent cap generates a 732 cm(-1) Raman band whose intensity scales linearly with the laser power delivered to the tissue of interest. In our first design, the FEP cap functions as a waveguide with only a small insertion loss (~5%). Laser transmission through 1 mm of the polymer is sufficient to generate a usable reference Raman signal. We show the application of the probe to quantitative non-invasive Raman spectroscopy of animal tissues using rat leg phantoms as models. Ex-vivo Raman spectroscopy of excised rat tibia supports the use of the probe for spectroscopy of various tissues. These results provide proof of principle that the Raman probe can be used in multiple spectroscopic applications.
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Affiliation(s)
- Paul I Okagbare
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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