A miniaturized electrochemical system with a novel polyelectrolyte reference electrode and its application to thin layer electroanalysis

Sang Kyung Kim, Hyojin Lim, Taek Dong Chung, Hee Chan Kim

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)

Abstract

Miniaturized liquid junction reference electrodes with short- and long-term stabilities were fabricated by using photopolymerization of a patterned polyelectrolytic hydrogel, poly diallyldimethylammonium chloride (pDADMAC). Internal and external solutions were separated by the polyelectrolytic hydrogel barrier, through which Cl- ions carried the ionic current. The impedance spectrum of the developed hydrogel-based salt bridge was flat at 40 kΩ, indicating negligible capacitance. Most of thin film-type reference electrodes patterned on microfluidic chips suffer from a short lifespan and complicated structure, which seriously antagonize the advantages of electrochemical detection. The novel reference electrode system using a polyelectrolyte salt bridge on a microfluidic chip maintained a reproducible potential of 19.3 ± 6 mV versus a commercial Ag/AgCl reference electrode over 30 h. Anionic interferents such as Br-, I-, and S2- ions had no influence on the performance of the reference electrode. In particular, the dependence on the Cl- ion concentration was substantially suppressed by separating the Ag/AgCl wire from the sample solution with the salt bridge. A 10 μm-thick cell with a polyelectrolyte salt bridge on a microfluidic chip showed the typical voltammetric behavior of thin layer cells that was confirmed by cyclic voltammetry (CV). This chip-based thin layer cell was exploited to determine the concentration of dopamine by differential pulse voltammetry (DPV) as well. A linear current response was observed down to 5 μM dopamine and the limit of detection was calculated to 2 μM.

Original languageEnglish
Pages (from-to)212-219
Number of pages8
JournalSensors and Actuators, B: Chemical
Volume115
Issue number1
DOIs
StatePublished - 23 May 2006

Fingerprint

Polyelectrolytes
Hydrogel
Salts
Electrodes
chips
electrodes
Microfluidics
Hydrogels
salts
dopamine
Ions
Dopamine
cells
Photopolymerization
Voltammetry
ion concentration
Cyclic voltammetry
ions
Capacitance
capacitance

Keywords

  • Differential pulse voltammetry (DPV)
  • Microfluidic chip
  • Polyelectrolyte reference electrode
  • Salt bridge
  • Thin layer cell

Cite this

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abstract = "Miniaturized liquid junction reference electrodes with short- and long-term stabilities were fabricated by using photopolymerization of a patterned polyelectrolytic hydrogel, poly diallyldimethylammonium chloride (pDADMAC). Internal and external solutions were separated by the polyelectrolytic hydrogel barrier, through which Cl- ions carried the ionic current. The impedance spectrum of the developed hydrogel-based salt bridge was flat at 40 kΩ, indicating negligible capacitance. Most of thin film-type reference electrodes patterned on microfluidic chips suffer from a short lifespan and complicated structure, which seriously antagonize the advantages of electrochemical detection. The novel reference electrode system using a polyelectrolyte salt bridge on a microfluidic chip maintained a reproducible potential of 19.3 ± 6 mV versus a commercial Ag/AgCl reference electrode over 30 h. Anionic interferents such as Br-, I-, and S2- ions had no influence on the performance of the reference electrode. In particular, the dependence on the Cl- ion concentration was substantially suppressed by separating the Ag/AgCl wire from the sample solution with the salt bridge. A 10 μm-thick cell with a polyelectrolyte salt bridge on a microfluidic chip showed the typical voltammetric behavior of thin layer cells that was confirmed by cyclic voltammetry (CV). This chip-based thin layer cell was exploited to determine the concentration of dopamine by differential pulse voltammetry (DPV) as well. A linear current response was observed down to 5 μM dopamine and the limit of detection was calculated to 2 μM.",
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A miniaturized electrochemical system with a novel polyelectrolyte reference electrode and its application to thin layer electroanalysis. / Kim, Sang Kyung; Lim, Hyojin; Chung, Taek Dong; Kim, Hee Chan.

In: Sensors and Actuators, B: Chemical, Vol. 115, No. 1, 23.05.2006, p. 212-219.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Lim, Hyojin

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