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Modified liquid junction interface for nonaqueous capillary electrophoresis‐mass spectrometry
Author(s) -
Jussila Matti,
Sinervo Kai,
Porras Simo P.,
Riekkola MarjaLiisa
Publication year - 2000
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(20000901)21:15<3311::aid-elps3311>3.0.co;2-n
Subject(s) - capillary electrophoresis , chemistry , capillary action , chromatography , analytical chemistry (journal) , electrospray ionization , capillary electrophoresis–mass spectrometry , mass spectrometry , electrospray , electrolyte , reproducibility , capillary electrochromatography , electrode , materials science , composite material
Electrospray ionization (ESI) is the most widely used ionization method in on‐line coupling of capillary electrophoresis‐mass spectrometry (CE‐MS). The conventional coaxial sheath flow electrospray interface is currently being replaced by the more sensitive nanoelectrospray technique. The usual limitation of nanoelectrospray CE‐MS interface has been its short lifetime caused by deterioration of the metal coating on the CE capillary terminus. This article describes an easy way to construct a more durable and sensitive nanospray interface for nonaqueous CE‐MS. In this approach a very thin glass spray capillary ( ca. 30 μm outer diameter) is partly inserted inside the CE capillary, the junction being surrounded by the electrolyte medium, which is in contact with the platinum electrode. The interface was tested with five pharmaceuticals: methadone, pentazocine, levorphanol, dihydrocodeine, and morphine. Detection limits ranged from 12 to 540 fmol. Separation efficiency and reproducibility were also studied. The CE current was found to be stable and the migration times were highly reproducible. All the CE separations were carried out in a nonaqueous background electrolyte solution.