Bipolar charging of ultrafine particles in the size range below 10 nm

Reischl, G.; Mäkelä, Jyrki M.; Karch, Rudolf; Necid, J.

doi:10.1016/0021-8502(96)00026-2

Cited by 197 publications

(152 citation statements)

References 65 publications

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“…Via recombination, primarily with negative ions, the clusters were brought close to a steady-state charge distribution 37,38 , wherein the cluster charge distribution was solely a function of cluster size and independent of initial charge state. Prior studies, both experimental 39 and theoretical 37 , show clearly that in the sub 10 nm size range (of interest here), at steady-state and for ions generated in air at room temperature, most clusters are neutral, and those that are charged are only singly charged (i.e. the charge state, z = ± 1).…”

Section: Figurementioning

confidence: 79%

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Higashi

Tokumi

Hogan

et al. 2015

Phys. Chem. Chem. Phys.

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We use a combination of tandem ion mobility spectrometry (IMS-IMS, with differential mobility analyzers), molecular dynamics (MD) simulations, and analytical models to examine both neutral solvent (H2O) and ion (solvated Na + ) evaporation from aqueous sodium chloride nanodrops. For experiments, nanodrops were produced via electrospray ionization (ESI) of an aqueous sodium chloride solution. Two nanodrops were examined in MD simulations: a 2,500 water molecule nanodrop with 68 Na + and 60 Cl -ions (an initial net charge of z = +8), and (2) a 1,000 water molecule nanodrop with 65 Na + and 60 Cl -ions (an initial net charge of z = +5). Specifically, we used MD simulations to examine the validity of a model for the neutral evaporation rate incorporating both the Kelvin (surface curvature) and Thomson (electrostatic) influences, while both MD simulations and experimental measurements were compared to predictions of the ion evaporation rate equation of Labowsky et al [Anal Chim Acta, 2000, 406, 105-118]. To within a single fit parameter, we find excellent agreement between simulated and modeled neutral evaporation rates for nanodrops with solute volume fractions below 0.30. Similarly, MD simulation inferred ion evaporation rates are in excellent agreement with predictions based on the Labowsky et al equation. Measurements of the sizes and charge states of ESI generated NaCl clusters suggest that the charge states of these clusters are governed by ion evaporation, however, ion evaporation appears to have occurred with lower activation energies in experiments than was anticipated based on analytical calculations as well as MD simulations. Several possible reasons for this discrepancy are discussed.

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Section: Figurementioning

confidence: 79%

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Higashi

Tokumi

Hogan

et al. 2015

Phys. Chem. Chem. Phys.

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“…The probability that a particle of diameter D j has Á elementary charges of the appropriate sign, f (D j ; Á), is described by Fuch's (1963) theory as modi ed by Hoppel and Frick (1986). The choice of appropriate ion properties may depend on the application, with those given by Reischl et al (1996) applicable for typical ambient conditions. To accelerate the calculations, the Wiedensohler (1988) approximation can also be used.…”

Section: Inversion Methodsmentioning

confidence: 99%

Improved Inversion of Scanning DMA Data

Collins

Flagan

Seinfeld

2002

Aerosol Science and Technology

147

126

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Recovery of aerosol size distributions from either stepping or scanning mode differential mobility analyzer (DMA) measurements requires an accurate description of the characteristics of the DMA itself, as well as certain properties of the aerosol. Inversion of scanning DMA data is further complicated by the nonunique relationship between the time a particle exits the DMA and the time it is ultimately detected. Without an accurate description of this relationship, and an appropriate method of accounting for it, inverted distributions will be broadened and skewed relative to the true distribution. A simpli ed approach to inversion of scanning DMA data is described here in which adjustment of the raw data to account for the delay time distribution associated with the instrument is accomplished prior to nal inversion. This provides the exibility to utilize more accurate descriptions of the delay time distribution and the DMA transfer function than is feasible if the inversion is to be accomplished in one step as described by Russell et al. (1995). The accuracy of this procedure has been demonstrated through analysis of actual as well as test-case data.

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“…A Po 210 ␣ radiation source (5 mCi, model P-2042 Nucleospot local air ionizer; NRD, Grand Island, NY) is embedded in the nano ES source and leads to a bipolar charging atmosphere. The highly charged nanodroplets, generated via electrospray process in the cone-jet mode, were transformed in the bipolar atmosphere into neutral and singly positively and negatively charged particles [9,10]. The so generated particles are transferred into the separation device (nano DMA in case of GEMMA or scanning nano DMA/sampling nano DMA in case of PDMA system).…”

Section: N-es Conditions For Gemma and Pdmamentioning

confidence: 99%

“…The size range of 10 to 200 nm is therefore of great interest, and covered by the so-called nano-differential mobility analysis (nano DMA) [8]. Combined with a modified nano electrospray source (nES) for nanoaerosol generation, and bipolar charging process to deliver mostly singly charged ions [9,10], it has been demonstrated that the analysis of intact biospecific protein complexes [11,12], viruses [11], virus antibody [13], virus receptor [13], bacterio phages [14], and polymers [15,16] is possible, and delivers a lot of new knowledge.…”

mentioning

confidence: 99%

Nano ES GEMMA and PDMA, new tools for the analysis of nanobioparticles—Protein complexes, lipoparticles, and viruses

Allmaier

Laschober

Szymanski

2008

J. Am. Soc. Mass Spectrom.

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Differential mobility analysis (DMA) is a technique suited for size analysis as well as preparative collection of airborne nanosized airborne particles. In the recent decade, the analysis of intact viruses, proteins, DNA fragments, polymers, and inorganic nanoparticles was possible when combining this method with a nano-electrospray charge-reduction source for producing aerosols from a sample solution/suspensions. Mass analysis of high molecular weight noncovalent complexes is also possible with this methodology due to the linear correlation of the electrophoretic mobility diameter and the molecular mass. In this work, we present the analysis (size and molecular mass) of high molecular weight multimers (noncovalent functional homocomplex) of Jack bean urease in a mass range from 275 kDa up to 2.5 MDa, with mainly present tri-and hexamers but also higher oligomers of the 91 kDa monomer subunit. In a second experiment, the size analysis of intact very-low-density (ϳ35 nm), low-density (ϳ22 nm) and high-density lipoparticles (ϳ10 nm), which are heterocomplexes consisting of cholesterol, lipids, and proteins in different ratios, is presented. Results from mobility analysis were in excellent agreement with particle diameters found in literature. The last presented experiment demonstrates size analysis of a rod-like virus and selective sampling of a selected size fraction of electrosprayed, singly-charged tobacco mosaic virus particles. Sampling and subsequent transmission electron microscopic investigations of a specific size fraction (40 nm electrophoretic mobility diameter) revealed the folding of virus particles during the electrospray and charge reduction (electrical stress) as well as solvent evaporation (mechanical stress) process, leading to an observed geometry of 150 (length) ϫ 35 (width) nm (average cylindrical geometry of unsprayed intact virus 300 ϫ 18 nm). and viruses. Analysis of the formation process, stoichiometry, and molecular weight of those complexes can be very challenging as noncovalent interactions can easily be destroyed or biased when leaving specific native conditions [5], and as their molecular mass can easily exceed the working range of modern mass spectrometry. For these reasons, a demand for new analytical techniques, which preserve noncovalent interactions, deliver molecular mass and/or size related information (in contrast to capillary electrophoresis and native gel electrophoresis) and which have a working range that exceed conventional mass spectrometry, exists.Differential mobility analysis (DMA) is a technique developed to classify charged aerosolized particles under ambient pressure according to their electrophoretic mobility diameter [6]. In the recent decade, its working range was extended from m down to the nm size range [7], or in terms of molecular mass, into the kDa to GDa molecular mass range, thus closing the gap between classic aerosol particle technology (low m into mm range) and mass spectrometry (sub-nm to 10 nm). The size range of 10 to 200 nm is therefore of great in...

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Bipolar charging of ultrafine particles in the size range below 10 nm

Cited by 197 publications

References 65 publications

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Improved Inversion of Scanning DMA Data

Nano ES GEMMA and PDMA, new tools for the analysis of nanobioparticles—Protein complexes, lipoparticles, and viruses

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