# On the mechanism of extractive electrospray ionization (EESI) in the dual-spray configuration

Author(s) Wang, Rui, Gröhn, Arto Juhani, Zhu, Liang, Dietiker, Rolf, Wegner, Karsten, Günther, Detlef, Zenobi, Renato
Publication Type Journal Items, Publication Status: Published
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Title On the mechanism of extractive electrospray ionization (EESI) in the dual-spray configuration
Author(s) Wang, Rui
Gröhn, Arto Juhani
Zhu, Liang
Dietiker, Rolf
Wegner, Karsten
Günther, Detlef
Zenobi, Renato
Journal or Series Title Analytical and bioanalytical chemistry
Volume Number 402
Issue Number 8
Start Page 2633
End Page 2643
ISSN 1618-2642
1618-2650
Publisher Springer
Publication Place Berlin
Publication Date 2012-03
Keyword(s) Mass spectrometry
Extractive electrospray
Ionization mechanisms
Abstract Dual-spray extractive electrospray ionization (EESI) mass spectrometry as a versatile analytical technique has attracted much interest due to its advantages over conventional electrospray ionization (ESI). The crucial difference between EESI and ESI is that in the EESI process, the analytes are introduced in nebulized form via a neutral spray and ionized by collisions with the charged droplets from an ESI source formed by spraying pure solvent. However, the mechanism of the droplet–droplet interactions in the EESI process is still not well understood. For example, it is unclear which type of droplet–droplet interaction is dominant: bounce, coalescence, disruption, or fragmentation? In this work, droplet–droplet interaction was investigated in detail based on a theoretical model. Phase Doppler anemometry (PDA) was employed to investigate the droplet behavior in the EESI plume and provide the experimental data (droplet size and velocity) necessary for theoretical analysis. Furthermore, numerical simulations were performed to clarify the influence of the sheath gas flow on the EESI process. No coalescence between the droplets in the ESI spray and the droplets in the sample spray was observed using various geometries and sample flow rates. Theoretical analysis, together with the PDA results, suggests that droplet fragmentation may be the dominant type of droplet–droplet interaction in the EESI. The interaction time between the ESI droplet and the sample droplet was estimated to be <5 μs. This work gives a clear picture of droplet–droplet interactions in the dual-spray EESI process and detailed information for the optimization of this method for future applications that require higher sensitivity
DOI 10.1007/s00216-011-5471-8
Additional Notes Received 29 July 2011, Revised 19 September 2011, Accepted 3 October 2011
Document Type Article
Publication Status Published
Language English
Assigned Organisational Unit(s) 03510
03430
03512
Organisational Unit(s)
NEBIS System Number 004239219
Source Database ID FORM-1321965633
WOS-000300852700016
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@article{Wng2012,
author = "Wang, Rui and Gr{\"{o}}hn, Arto Juhani and Zhu, Liang and Dietiker, Rolf and Wegner, Karsten and G{\"{u}}nther, Detlef and Zenobi, Renato",
title = "{O}n the mechanism of extractive electrospray ionization ({E}{E}{S}{I}) in the dual-spray configuration",
journal = "Analytical and bioanalytical chemistry",
year = 2012,
volume = "402",
number = "8",
pages = "2633--2643",
month = mar,
}


E-Citations record created: Tue, 22 Nov 2011, 12:40:39 CET