Interfacing capillary-based separations to mass spectrometry using desorption electrospray ionization

Griffin K. Barbula, Samir Safi, Konstantin Chingin, Richard H. Perry, Richard N. Zare

Research output: Contribution to journalArticlepeer-review

Abstract

The powerful hybrid analysis method of capillarybased separations followed by mass spectrometric analysis gives substantial chemical identity and structural information. It is usually carried out using electrospray ionization. However, the salts and detergents used in the mobile phase for electrokinetic separations suppress ionization efficiencies and contaminate the inlet of the mass spectrometer. This report describes a new method that uses desorption electrospray ionization (DESI) to overcome these limitations. Effluent from capillary columns is deposited on a rotating Teflon disk that is covered with paper. As the surface rotates, the temporal separation of the eluting analytes (i.e., the electropherogram) is spatially encoded on the surface. Then, using DESI, surface-deposited analytes are preferentially ionized, reducing the effects of ion suppression and inlet contamination on signal. With the use of this novel approach, two capillary-based separations were performed: a mixture of the rhodamine dyes at milligram/milliliter levels in a 10 mM sodium borate solution was separated by capillary electrophoresis, and a mixture of three cardiac drugs at milligram/milliliter levels in a 12.5 mM sodium borate and 12.5 mM sodium dodecyl sulfate solution was separated by micellar electrokinetic chromatography. In both experiments, the negative effects of detergents and salts on the MS analyses were minimized.

Original languageEnglish (US)
Pages (from-to)1955-1959
Number of pages5
JournalAnalytical Chemistry
Volume83
Issue number6
DOIs
StatePublished - Mar 15 2011

ASJC Scopus subject areas

  • Analytical Chemistry

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