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Nano‐liquid chromatography—direct electron ionization mass spectrometry: improving performance by a new ion source adapter
Author(s) -
Flender Cornelia,
Wolf Christian,
Leonhard Peter,
Karas Michael
Publication year - 2011
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1981
Subject(s) - chemistry , mass spectrometry , adapter (computing) , analytical chemistry (journal) , direct electron ionization liquid chromatography–mass spectrometry interface , ion source , ionization , detection limit , chromatography , dart ion source , chemical ionization , electron ionization , ion , organic chemistry , electrical engineering , engineering
A novel interface adapter has been designed to provide a new way of directly coupling a nano‐liquid chromatograph to an electron ionization mass spectrometer. It connects the transfer capillary coming from the liquid chromatograph to the ionization chamber and can be easily screwed into the ion source. Liquid coming from the column passes through the heated adapter flow path and is vaporized. A continuous flow of new liquid pushes the vapor into the ionization chamber where it is ionized and continues on to the mass analyzer. The advantages of the new adapter are reduced ice formation inside the ion source and less clogging of the transfer capillary. Improvements achieved are demonstrated on the basis of caffeine and steroid analysis. The limits of detection of selected steroids are compared with and without the adapter. The adapter improves the detection limit of the system by a factor of 2 and precision from ≤15% to ≤9% relative standard deviation. No derivatization procedure is necessary before the analysis of small polar compounds. The resulting spectra are reproducible, easily interpretable, and database searchable. The new method is robust, delivers reproducible results, and provides a highly efficient alternative to existing methods in the field of pharmaceutical analysis. Copyright © 2011 John Wiley & Sons, Ltd.