Czech Society for Mass Spectrometry

(CEEPC/IPM/CMSC 2022 - FrP-10)
The use of mobile phase with a low formic acid concentration in LC-MS proteomic analysis leads to enhanced electrospray ionization and improved sensitivity

Siddharth Jadeja ^1 *, Hana Sklenářová ¹, Juraj Lenčo ¹

1. Faculty of Pharmacy, Charles University

Abstract

When liquid chromatography is hyphenated to mass spectrometry for analysis of protein samples, the use of a mobile phase with high ionic strength is not recommended as it causes inefficient electrospray ionization [1]. Formic acid at a concentration of 0.1% has been a popular choice as an acidifier for its decent ion-pairing ability and relatively low MS signal suppression. In this study, analytical columns packed with a charged surface hybrid (CSH) stationary phase, designed to function efficiently with mobile phases of low ionic strength [2], were used to evaluate MS sensitivity gain and extent of peptide identification at a varied concentration of formic acid in the mobile phase (0.1% to 0.01%). Well-characterized peptides, a digested monoclonal antibody, and a complex bacterial sample were included in this study to evaluate the effect on varying sample complexity. About 40% to 50% gain in the MS sensitivity was observed using mobile phases with reduced formic acid. Furthermore, the number of identified peptides was increased when using the mobile phase with lower formic acid concentration. CSH stationary phases have opened doors for proteomic LC-MS analysis to use mobile phases with a minimal concentration of formic acid as an acidifier and exploit the advantages of the enhanced MS detection with no peak distortion.

* Corresponding author: jadejas@faf.cuni.cz

References

1. García, M. C.: J. Chromatogr. B 825 (2), 111-123 (2005)
2. Nováková, L. et al.: Talanta 93, 99–105 (2012)

Acknowledgement:

The study was supported by Grant Agency of Charles University (GAUK No. 370522) co-funded by ERDF and by specific research project No. SVV 260548