Microfluidic ion stripper for removal of trifluoroacetic acid from mobile phases used in HILIC-MS of intact proteins

S. Wouters, S. Eeltink, R. Haselberg, G.W. Somsen, A.F.G. Gargano

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

© 2021, The Author(s).Trifluoroacetic acid (TFA) is commonly used as mobile phase additive to improve retention and peak shape characteristics in hydrophilic interaction liquid chromatography (HILIC) of intact proteins. However, when using electrospray ionization-mass spectrometry (ESI-MS) detection, TFA may cause ionization suppression and adduct formation, leading to reduced analyte sensitivity. To address this, we describe a membrane-based microfluidic chip with multiple parallel channels for the selective post-column removal of TFA anions from HILIC. An anion-exchange membrane was used to physically separate the column effluent from a stripper flow solution comprising acetonitrile, formic acid, and propionic acid. The exchange of ions allowed the post-column removal of TFA used during HILIC separation of model proteins. The multichannel design of the device allows the use of flow rates of 0.2 mL/min without the need for a flow splitter, using mobile phases containing 0.1% TFA (13 mM). Separation selectivity and efficiency were maintained (with minor band broadening effects) while increasing the signal intensity and peak areas by improving ionization and reducing TFA adduct formation. Graphical abstract: [Figure not available: see fulltext.]
Original languageEnglish
Pages (from-to)4379-4386
JournalAnalytical and Bioanalytical Chemistry
Volume413
Issue number17
DOIs
Publication statusPublished - 1 Jul 2021

Funding

S. Wouters acknowledges financial support from the Flemish Agency for Innovation and Entrepreneurship. S. Eeltink acknowledges a research grant of the Research Foundation Flanders (FWO – grant no. G033018N). AG acknowledges financial support by the Netherlands Organization for Scientific Research, NWO Veni grant IPA (722.015.009).

FundersFunder number
Flemish Agency for Innovation and Entrepreneurship
Fonds Wetenschappelijk OnderzoekG033018N
Nederlandse Organisatie voor Wetenschappelijk Onderzoek722.015.009

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