Premium
Capillary electrophoresis with end‐capillary potentiometric detection using a copper electrode
Author(s) -
Macka Miroslav,
Gerhardt Geoff,
Andersson Per,
Bogan Declan,
Cassidy Richard M.,
Haddad Paul R.
Publication year - 1999
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/(sici)1522-2683(19990801)20:12<2539::aid-elps2539>3.0.co;2-0
Subject(s) - capillary electrophoresis , capillary action , potentiometric titration , detection limit , capillary electrochromatography , electrode , analytical chemistry (journal) , chromatography , chemistry , electrolyte , copper , potentiometric sensor , materials science , organic chemistry , composite material
Potentiometric end‒capillary detection in capillary electrophoresis has the advantage of relatively easy miniaturisation without having to compromise the concentration sensitivity. Potentiometric end‒capillary detection using a copper electrode is also attractive because of the sensitive detection of many inorganic and organic UV‒transparent ions and the ability to work in both direct and indirect mode. In this work, detection of a number of common anions in a tartrate electrolyte at pH 3 was studied. The influence of the end‒capillary detection geometry on the detection performance was investigated. An end‒capillary detection cell allowing the separation capillary to be changed without the need to realign the detection electrode was constructed and fitted into a commercial CE apparatus. Under the optimal configuration, which was a 25 μm diameter copper electrode aligned coaxially with a 25 μm capillary and positioned at a distance of about 25 μm from the capillary end, excellent peak shapes were achieved and comparison with simultaneous on‒capillary photometric detection showed no additional peak broadening. Good sensitivity was obtained, resulting in concentration limits of detection (LODs) in the low μ M range and mass LODs in the low amol range. Examples of separations of inorganic and organic anions are presented and the analytical potential of the detection method is assessed.