Toward developing a micro HPLC cartridge, we have recently built a high-pressure electroosmotic pump (EOP). However, we do not recommend people to use this pump to deliver an organic solvent directly, because it often makes the pump rate unstable. We have experimented several approaches to address this issue, but none of them are satisfactory. Here, we develop an innovative approach to address this issue. We first create an abruption (a dead-volume) within a fluid conduit. We then utilize an EOP to withdraw, via a selection valve, a train of eluent solutions having decreasing eluting power into the fluid conduit. When these solutions are further aspirated through the dead-volume, these solutions are partially mixed, smoothening concentration transitions between two adjacent eluent solutions. As these solutions are pushed back, through the dead-volume again, a smooth gradient profile is formed. In this work, we characterize this scheme for gradient formation, and we incorporate this approach with a high-pressure EOP, a nanoliter injection valve, and a capillary column, yielding a micro HPLC system. We then couple this micro HPLC with an electrospray ionization – mass spectrometer for peptide and protein separations and identifications.

Item Type:	Refereed Article
Keywords:	electroosmotic pump, anoflow, gradient generator, high performance liquid chromatography, mass spectrometry
Research Division:	Chemical Sciences
Research Group:	Analytical Chemistry
Research Field:	Separation Science
Objective Division:	Manufacturing
Objective Group:	Human Pharmaceutical Products
Objective Field:	Human Diagnostics
Author:	Zhang, M (Dr Min Zhang)
ID Code:	104665
Year Published:	2015
Web of Science® Times Cited:	6
Deposited By:	Chemistry
Deposited On:	2015-11-18
Last Modified:	2018-03-16
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