Influence of electrolytes and a supercharging reagent on charge state distribution and response of neuropeptide ions generated during positive electrospray ionisation mass spectrometry
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Nielsen, Birthe V. 
ORCID: https://orcid.org/0000-0002-0849-4987 and Abaye, Daniel A.
(2013)
Influence of electrolytes and a supercharging reagent on charge state distribution and response of neuropeptide ions generated during positive electrospray ionisation mass spectrometry.
European Journal of Mass Spectrometry, 19 (5).
pp. 335-344.
ISSN 1469-0667 (Print), 1751-6838 (Online)
(doi:10.1255/ejms.1246)
Abstract
To aid in the detection of trace quantities of neuropeptides in a biological matrix (as saliva), the influence of different electrolytes and a supercharging reagent on the positive electrospray ionisation mass spectrometry (ESI-MS) response was investigated. Ammonium acetate, sodium chloride and sodium bicarbonate (10–7 M to 10–3 M) and the supercharging reagent m-nitrobenzyl alcohol (m-NBA) was added to the mobile phase and the effect on the ESI response and charge-states distribution (CSD) was studied in a group of peptides (molecular weight range 2.2 kDa to 3.5 kDa; CGRP, VIP, GLP1, CRF and PrRP). As expected, the result indicates that the ESI response is affected by the presence of additives: ammonium acetate shifted the observed charge states ratio whereas the addition of m-NBA resulted in the appearance of higher maximum charge state ions. This increase in higher charge state for all the peptide ions, [M + nH]n+ to [M + (n +?1)H]n + 1, was atttributed to protonation of the C-terminal. However, when the composition of MeCN in a mobile phase �containing m-NBA was increased, an enhancement of the total ion signal was observed for non-polar peptide samples. This is a very interesting observation as this is not observed in samples without m-NBA and could be a result of how these peptide ions are solubilised and �positioned relative to the droplet surface/air interface.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ESI-MS, electrolytes, biologically-active peptides, CSD |
| Subjects: | Q Science > QD Chemistry |
| Pre-2014 Departments: | School of Science |
| Related URLs: | |
| Last Modified: | 16 May 2019 12:34 |
| URI: | http://gala.gre.ac.uk/id/eprint/10982 |
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