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On‐line sample preconcentration by polarity switching in floating electrode‐integrated microchannel
Author(s) -
Kitagawa Fumihiko,
TanigawaJoh Kana,
Terashita Satomi,
Fujiki Ryohei,
Nukatsuka Isoshi,
Sueyoshi Kenji,
Otsuka Koji
Publication year - 2019
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.201800501
Subject(s) - electrode , polarity (international relations) , anode , analytical chemistry (journal) , analyte , materials science , chemistry , electrophoresis , chromatography , biochemistry , cell
In this study, we found that the polarity switching was effective to enrich and separate fluorescent analytes which have weakly‐dissociated groups in a floating platinum electrode (width, 50 µm; thickness, 2.5 µm)‐integrated straight‐channel in microchip electrophoresis (MCE). In the straight channel filled with an Alexa Flour 488 (AF488) solution, a sharp peak was observed after the polarity inversion with a 530‐fold enhancement of the sensitivity relative to the conventional MCE analysis. By using a fluorescent pH indicator, we verified that a sharp high‐pH zone was generated nearby the floating electrode and moved toward the anode with maintaining the high pH, which induced the sample enrichment like a dynamic pH junction mechanism. In the floating electrode‐embedded channel, the mixture of AF488‐labeled proteins was also well concentrated and separated within 100 s.