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Electrospray droplet impact secondary ion mass spectrometry using a vacuum electrospray source
Author(s) -
Takaishi R.,
Sakai Y.,
Hiraoka K.,
Wada H.,
Morita S.,
Nakashima T.,
ami H.
Publication year - 2015
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7240
Subject(s) - chemistry , electrospray , analytical chemistry (journal) , extractive electrospray ionization , electrospray ionization , mass spectrometry , chromatography , atmospheric pressure , desorption electrospray ionization , ion source , ion , sample preparation in mass spectrometry , thermal ionization mass spectrometry , organic chemistry , oceanography , geology
Rationale In electrospray droplet impact (EDI) developed in our laboratory, an atmospheric pressure electrospray source has been used. To increase the ion beam intensity and reduce the evacuation load, a vacuum electrospray cluster ion source using a silica capillary was developed. Methods A silica capillary with a tip inner diameter of 8 µm was used for vacuum electrospray using aqueous 10% methanol. To stabilize the flow rate of the liquid for nano‐electrospray, a home‐made constant pressure liquid pump was also developed. Results By using the silica tip nano‐electrospray emitter and a constant pressure pump, stable electrospray with flow rate of 22 nL/min was realized without using any heating system such as laser irradiation. Comparative study of mass spectra obtained by atmospheric pressure EDI (A‐EDI) and vacuum EDI (V‐EDI) was made for various samples such as thermometer molecule, peptide, polystyrene, Alq 3 , NPD, C 60 , indium, and SiO 2 . V‐EDI showed slightly milder ionization than A‐EDI. Conclusions Because V‐EDI gave higher target current (5–10 nA) than A‐EDI (a few nA at most), V‐EDI secondary ion mass spectrometry (SIMS) would be a useful technique for the surface and interface analysis. Copyright © 2015 John Wiley & Sons, Ltd.