Electrospray ionization mass spectrometry from discrete nanoliter-sized sample volumes
Article first published online: 27 JUL 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 24, Issue 17, pages 2561–2568, 15 September 2010
How to Cite
Ek, P., Stjernström, M., Emmer, Å. and Roeraade, J. (2010), Electrospray ionization mass spectrometry from discrete nanoliter-sized sample volumes. Rapid Commun. Mass Spectrom., 24: 2561–2568. doi: 10.1002/rcm.4674
- Issue published online: 27 JUL 2010
- Article first published online: 27 JUL 2010
- Manuscript Accepted: 19 JUN 2010
- Manuscript Revised: 17 JUN 2010
- Manuscript Received: 7 MAY 2010
We describe a method for nanoelectrospray ionization mass spectrometry (nESI-MS) of very small sample volumes. Nanoliter-sized sample droplets were taken up by suction into a nanoelectrospray needle from a silicon microchip prior to ESI. To avoid a rapid evaporation of the small sample volumes, all manipulation steps were performed under a cover of fluorocarbon liquid. Sample volumes down to 1.5 nL were successfully analyzed, and an absolute limit of detection of 105 attomole of insulin (chain B, oxidized) was obtained. The open access to the sample droplets on the silicon chip provides the possibility to add reagents to the sample droplets and perform chemical reactions under an extended period of time. This was demonstrated in an example where we performed a tryptic digestion of cytochrome C in a nanoliter-sized sample volume for 2.5 h, followed by monitoring the outcome of the reaction with nESI-MS. The technology was also utilized for tandem mass spectrometry (MS/MS) sequencing analysis of a 2 nL solution of angiotensin I. Copyright © 2010 John Wiley & Sons, Ltd.