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Liberating Native Mass Spectrometry from Dependence on Volatile Salt Buffers by Use of Gábor Transform
Author(s) -
Cleary Sean P.,
Prell James S.
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900022
Subject(s) - chemistry , mass spectrometry , salt (chemistry) , electrospray ionization , ion , ion mobility spectrometry , ammonium acetate , polyethylene glycol , adduct , analytical chemistry (journal) , chromatography , ion mobility spectrometry–mass spectrometry , cluster (spacecraft) , sample preparation in mass spectrometry , organic chemistry , high performance liquid chromatography , computer science , programming language
Volatile salts, such as ammonium acetate, are commonly used in buffers for the analysis of intact proteins and protein complexes in native electrospray ionization mass spectrometry. Although these solutions are not technically buffers near pH 7, the volatile nature of the salt minimizes ion adduction to proteins upon transfer to vacuum. Conversely, common biochemical salt buffers, such as Tris/NaCl, are not traditionally used in native mass spectrometry because of the tendency of sodium and other ions to adduct to proteins or form large cluster ions, severely frustrating accurate mass assignment. Here, we demonstrate a Gábor transform method for extracting signal from native‐like protein ions even in the presence of a large salt‐cluster background. We further show the utility of this method in characterizing polymers and show that the measured average mass of long‐chain polyethylene glycol ions from a commercial polymer sample is ∼30 % higher than the manufacturer‐estimated average mass. It is expected that this method will enable more widespread use of conventional biochemical buffers in native mass spectrometry and decrease dependence on volatile salts.