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On‐line two‐dimensional capillary electrophoresis with mass spectrometric detection using a fully electric isolated mechanical valve
Author(s) -
Kohl Felix J.,
Montealegre Cristina,
Neusüß Christian
Publication year - 2016
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/elps.201500579
Subject(s) - capillary electrophoresis , bioanalysis , chromatography , electrolyte , capillary action , analytical chemistry (journal) , ultraviolet , mass spectrometry , dimension (graph theory) , sample (material) , chemistry , sample preparation , resolution (logic) , materials science , optoelectronics , computer science , electrode , mathematics , pure mathematics , composite material , artificial intelligence
CE is becoming more and more important in many fields of bioanalytical chemistry. Besides optical detection, hyphenation to ESI‐MS detection is increasingly applied for sensitive identification purposes. Unfortunately, many CE techniques and methods established in research and industry are not compatible to ESI‐MS since essential components of the background electrolyte interfere in ES ionization. In order to identify unknown peaks in established CE methods, here, a heart‐cut 2D‐CE separation system is introduced using a fully isolated mechanical valve with an internal loop of only 20 nL. In this system, the sample is separated using potentially any non‐ESI compatible method in the first separation dimension. Subsequently, the portion of interest is cut by the internal sample loop of the valve and reintroduced to the second dimension where the interfering compounds are removed, followed by ESI‐MS detection. When comparing the separation efficiency of the system with the valve to a system using a continuous capillary only a slight increase in peak width is observed. Ultraviolet/visible detection is integrated in the first dimension for switching time determination, enabling reproducible cutting of peaks of interest. The feasibility of the system is successfully demonstrated by a 2D analysis of a BSA tryptic digest sample using a nonvolatile (phosphate based) background electrolyte in the first dimension.