Coulometric microdevice for organophosphate pesticide detection

Jin Wang, Hiroaki Suzuki, Takaaki Satake

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


A coulometric microdevice based on plug-based microfluidics was developed for the detection of organophosphate pesticides (OPs). Detection was based on the inhibition of an enzyme, acetylcholinesterase (AChE), by the OPs. Hydrogen peroxide (H2O2), produced in a series of enzymatic reactions involving AChE and choline oxidase (ChOx), was oxidized on a microelectrode array, and changes in AChE activity upon addition of an OP were measured by coulometry. A linear relationship was confirmed between the charge generated and the logarithm of the OP concentration. The lower limit of detection (LOD) was 33 nM for malathion and 90 nM for acephate, MEP, and diazinon. An increase in the ratio of organic solvents was also found to inhibit AChE activity. However, the concentrations sufficient to produce this effect were several orders of magnitude higher than those of the OPs, indicating that this influence can be ignored in the analysis of OPs.

Original languageEnglish
Pages (from-to)297-301
Number of pages5
JournalSensors and Actuators, B: Chemical
Publication statusPublished - Dec 1 2014
Externally publishedYes


  • Acetylcholinesterase
  • Choline oxidase
  • Coulometry
  • Liquid plug
  • Organophosphate pesticide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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