Micro‐droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment

Chang, Yuan‐Pin; Devi, Yanita; Chen, Chun‐Hu

doi:10.1002/asia.202100516

Cited by 4 publications

(3 citation statements)

References 274 publications

(170 reference statements)

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“…The aerosol optical tweezers apparatus utilized in our present work has been described elsewhere, , and thus it is only briefly described here. A continuous-wave (CW) laser emitting at 532 nm was used as a trapping laser.…”

Section: Methodsmentioning

confidence: 99%

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

et al. 2023

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The sulfur oxidation in mixed sodium thiosulfate/sucrose/aqueous microdroplets by gaseous ozone is studied in this work via aerosol optical tweezers coupled with Raman spectroscopy, which can simultaneously determine various physicochemical properties and the heterogeneous reaction kinetics of single optically trapped microdroplets, allowing for elucidating their complicated interplay. According to the kinetics measurement results at different relative humidities, ozone concentrations, and stoichiometries of inorganic and organic solutes, this work finds that a high aerosol ionic strength can accelerate the ozone oxidation of thiosulfate at air−water interfaces, while a high aerosol viscosity prolongs the reaction time scales due to diffusion-limited kinetics. The kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB) is utilized to investigate the observed heterogeneous kinetics results and to retrieve the surface reaction rate coefficients. The KM-SUB model fit results indicate that the observed kinetics of sulfur oxidation in binary sodium thiosulfate aqueous microdroplets with high ionic strengths is dominated by interfacial reactions, and the fitted surface reaction rate coefficients increase 1 order of magnitude when the droplet ionic strength increases around 40 M. This work further utilizes the kinetics measurements of ozone dependence to discuss the coupling among properties of ozone gas-interface-bulk partitioning and surface reaction rate in the kinetics model. Finally, this work also exploits the surface reaction of thiosulfate with ozone to retrieve the aerosol viscosity of microdroplets containing ternary aqueous sodium thiosulfate and sucrose mixtures, demonstrating the feasibility of pinning down aerosol viscosities via reaction kinetics.

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Section: Methodsmentioning

confidence: 99%

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

et al. 2023

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“…The aerosol optical tweezers apparatus utilized in our present work has been described elsewhere, 23,46 and thus it is only briefly described here. A CW laser emitting at 532 nm was used as a trapping laser.…”

Section: Methodsmentioning

confidence: 99%

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

Hsu

Lin

Huang

et al. 2023

Preprint

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The sulfur oxidation in mixed sodium thiosulfate/sucrose/aqueous micro-droplets by gaseous ozone is studied in this work via aerosol optical tweezers coupled with Raman spectroscopy, which can simultaneously determine various physicochemical proper- ties and the heterogeneous reaction kinetics of single optically trapped micro-droplets, allowing for elucidating their complicate interplay. According to the kinetics measurement results at different relative humidities, ozone concentrations and stoichiometries of inorganic and organic solutes, this work finds that a high aerosol ionic strength can accelerate the ozone oxidation of thiosulfate at air-water interfaces, while a high aerosol viscosity prolongs the reaction timescales due to diffusion-limited kinetics. The kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB) is utilized to investigate the observed heterogeneous kinetics results and to retrieve the surface reaction rate coefficients. The KM-SUB simulations results indicate that the observed kinetics of sulfur oxidation in binary sodium thiosulfate aqueous micro-droplets with high ionic strengths is dominated by interfacial reactions, and the fitted surface reaction rate coefficients increase one order of magnitude when the droplet ionic strength increases around 40 M. Furthermore, this work demonstrated that including the effects of inter- facial ion depletion in the kinetics simulations can lead to an excellent agreement with the experimental results, implying its potential role in the interfacial kinetics.

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“…The AOT utilized in this work has been described elsewhere, [12,13] and thus only a brief description is provided here. A continuous-wave (CW) laser emitting at 532 nm was utilized as a trapping laser, and it was focused by a high numerical aperture oil-immersion objective into an aerosol trapping chamber that was made of three-dimensional (3D) printed poly-lactic acid.…”

Section: Methodsmentioning

confidence: 99%

Ozone oxidation of cysteine in optically trapped aqueous micro‐droplets

Chang

2023

J Chinese Chemical Soc

Self Cite

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The ozone (O3) oxidation kinetics of cysteine in aqueous micro‐droplets at different acidities is investigated in this study via aerosol optical tweezers coupled with Raman spectroscopy. This study exploits the O3 oxidation of cysteine near the interface of micro‐droplets as a model system to elucidate the oxidation damage of amino acids in biosurfaces. For each optically trapped micro‐droplet, Raman spectroscopy is used to determine its droplet radius, concentrations of solutes, and droplet pH, as well as their time evolutions during the kinetics measurements. The bimolecular rate coefficients of the cysteine + O3 reaction measured in micro‐droplets are around 4 × 105 M−1 s−1 and 2 × 104 M−1 s−1 for pH ≈ 5 and 0.5, respectively. These results agree with the previous bulk measurements, indicating that the observed aerosol kinetics can be solely rationalized via diffusion‐limited kinetics. The results also indicate that a high‐ionic strength could enhance the cysteine + O3 reaction, particularly for the zwitterion form of cysteine. The results imply that when surfactant proteins in lung fluids are exposed to ambient O3, the cysteine residues in proteins will be attacked by O3 at first due to the high reactivity of the thiol moiety in cysteine.

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Micro‐droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment

Cited by 4 publications

References 274 publications

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

Accelerated Sulfur Oxidation by Ozone on Surfaces of Single Optically Trapped Aerosol Particles

Ozone oxidation of cysteine in optically trapped aqueous micro‐droplets

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