Effects of Tailored Surface Chemistry on Desorption Electrospray Ionization Mass Spectrometry: a Surface-Analytical Study by XPS and AFM


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Date

2015-08

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Since it was proposed for the first time, desorption electrospray ionization-mass spectrometry (DESI-MS) has been evaluated for applicability in numerous areas. Elucidations of the ionization mechanisms and the subsequent formation of isolated gas-phase ions have been proposed so far. In this context, the role of both surface and pneumatic effects on ion-formation yield has recently been investigated. Nevertheless, the effect of the surface chemistry has not yet been completely understood. Functionalized glass surfaces have been prepared, in order to tailor surface performance for ion formation. Three substrates were functionalized by depositing three different silanes [3-mercaptopropyltriethoxysilane (MTES), octyltriethoxysilane (OTES), and 1H,1H,2H,2H-perfluorooctyltriethoxy-silane (FOTES)] from toluene solution onto standard glass slides. Surface characterization was carried out by contact-angle measurements, tapping-mode atomic force microscopy, and X-ray photoelectron spectroscopy. Morphologically homogeneous and thickness-controlled films in the nm range were obtained, with surface free energies lying between 15 and 70 mJ/m2. These results are discussed, together with those of DESI-MS on low-molecular-weight compounds such as melamine, tetracycline, and lincomycin, also taking into account the effects of the sprayer potential and its correlation with surface wettability. The results demonstrate that ion-formation efficiency is affected by surface wettability, and this was demonstrated operating above and below the onset of the electrospray.

Publication status

published

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Volume

26 (8)

Pages / Article No.

1311 - 1319

Publisher

Springer

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Subject

Desorption electrospray ionization; Mass spectrometry; Ionization; mechanism; Surface functionalization; Self-assembled monolayers; X-ray photoelectron spectroscopy

Organisational unit

03389 - Spencer, Nicholas (emeritus) / Spencer, Nicholas (emeritus) check_circle

Notes

It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.

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