Cluster activation studies with a diffusive condensation particle counter: Effect of chemical composition

Mora, Juan Fernández de la; Kangasluoma, Juha; Attoui, Michel

doi:10.1016/j.jaerosci.2021.105917

Cited by 5 publications

(1 citation statement)

References 30 publications

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“…We note that in calculating these growth ratios, n = 2 (doubly charged) serves as the input into the Stokes–Millikan equation. Different growth factors for different charge states would likely suggest issues with calibration or in the data analysis approach employed as Coulombic influences in both singly and doubly charged protein ions in the size range are not significant enough to influence vapor uptake (though it can have a substantial effect at higher charge levels, or the single nanometer scale). − Figure d–f display the growth factors of multimers of bovine serum albumin. Multimeric ion growth factors show the same tendency as monomer ions; larger proteins grew more with water vapor and smaller proteins grew more with nonane and 1-butanol vapor, and the effect is small with bovine serum albumin.…”

Section: Resultsmentioning

confidence: 99%

Condensable Vapor Sorption by Low Charge State Protein Ions

2022

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Measurement of the gas-phase ion mobility of proteins provides a means to quantitatively assess the relative sizes of charged proteins. However, protein ion mobility measurements are typically singular values. Here, we apply tandem mobility analysis to low charge state protein ions (+1 and +2 ions) introduced into the gas phase by nanodroplet nebulization. We first determine protein ion mobilities in dry air and subsequently examine shifts in mobilities brought about by the clustering of vapor molecules. Tandem mobility analysis yields mobility-vapor concentration curves for each protein ion, expanding the information obtained from mobility analysis. This experimental procedure and analysis is extended to bovine serum albumin, transferrin, immunoglobulin G, and apoferritin with water, 1-butanol, and nonane. All protein ions appear to adsorb vapor molecules, with mobility "diameter" shifts of up to 6−7% at conditions just below vapor saturation. We parametrize results using κ-Koḧler theory, where the term κ quantifies the extent of uptake beyond Koḧler model expectations. For 1-butanol and nonane, κ decreases with increasing protein ion size, while it increases with increasing protein ion size for water. For the systems probed, the extent of mobility shift for the organic vapors is unaffected by the nebulized solution pH, while shifts with water are sensitive to pH.

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Section: Resultsmentioning

confidence: 99%