Electropreconcentration-induced local pH change

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8 Citations (Scopus)


Ion-permselective nanochannel-based sample preconcentration or electropreconcentration has been demonstrated as an effective technique for concentrating charged analytes at the interface between a micro- and nanochannel. The anion-selective electropreconcentration involves extraction of hydroxide in the preconcentrated sample plug, resulting in pH decrease. We investigated the pH change in a microchannel using charged pH indicators with different conditions including running buffer pH, sample channel electric field, and salt concentration. The anion-selective preconcentration showed pH decrease from 11 to under 7 in the preconcentrated sample plug. Therefore, careful design and interpretation are required with pH-dependent experiments such as analyzing enzyme or antibody characteristics. The pH change could be mitigated by reducing the sample channel electric field and/or increasing salt concentration in the buffer.

Original languageEnglish
Pages (from-to)521-525
Number of pages5
Issue number3
Publication statusPublished - 2018 Feb

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) (NRF-2013M3A6A4046061, NRF-2012-0009556, and NRF-2011-0031866).

Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • Electropreconcentration
  • Local pH change
  • Sample preconcentration

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry


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