Peak capacity of ion mobility mass spectrometry: the utility of varying drift gas polarizability for the separation of tryptic peptides

• Published in: Journal of mass spectrometry. 2004-04, Vol.39 (4), p.361-367
• Main Authors: Ruotolo, Brandon T., McLean, John A., Gillig, Kent J., Russell, David H.
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; conformation; Fructose-Bisphosphate Aldolase - chemistry; Fructose-Bisphosphate Aldolase - isolation & purification; Fructose-Bisphosphate Aldolase - metabolism; Fundamental and applied biological sciences. Psychology; Gases - chemistry; General aspects, investigation methods; Kinetics; Mass Spectrometry - methods; matrix-assisted laser desorption/ionization; Peptide Fragments - chemistry; Peptide Fragments - isolation & purification; Peptide Fragments - metabolism; peptides; Proteins; proteomics; Rabbits; separation; Trypsin - metabolism
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/jms.592

Ion mobility mass spectrometry (IM‐MS) peptide mass mapping experiments were performed using a variety of drift gases (He, N2, Ar and CH4). The drift gases studied cover a range of polarizabilities ((0.2–2.6) × 10−24 cm3) and the peak capacities obtained for tryptic peptides in each gas are compared. Although the different gases exhibit similar peak capacities (5430 (Ar) to 7580 (N2)) in some cases separation selectivity presumably based on peptide conformers (or conformer populations), is observed. For example the drift time profiles observed for some tryptic peptide ions from aldolase (rabbit muscle) show a dependence on drift gas. The transmission of high‐mass ions (m/z > 2000) is also influenced by increased scattering cross‐section of the more massive drift gases. Consequently the practical peak capacity for IM‐MS separation cannot be assumed to be solely a function of resolution and the ability of a gas to distribute signals in two‐dimensional space; rather, peak capacity estimates must account for the transmission losses experienced for peptide ions as the drift gas mass increases. Copyright © 2004 John Wiley & Sons, Ltd.