A potentiometric biosensor for pesticides based on the thiocholine hexacyanoferrate (III) reaction

D. M. Ivnitskii*, J. Rishpon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


A solid-state acetylcholinesterase (AChE) sensor was developed on the basis of AChE acetylthiocholine-hexacyanoferrate (III) reaction. Various properties of the sensor were investigated and possibilities for its practical use in the detection and assay of pesticides are suggested. The response of the sensor was induced by two phenomena: the Donnan effect and the redox potential. Unlike pH-sensitive sensors, this type of sensor is operated at high ionic strength and a high buffer capacity. The ability of the AChE sensor to assay pesticides was demonstrated by the characterization and quantitative determination of dichlorvos based on its inhibition of AChE. The kinetics of inhibition by dichlorvos of the reaction with AChE were studied by potentiometric and photometric methods. The bimolecular reaction constant was 7·07 105 M-1 min-1 and the affinity constant was 4·76 10-6 M. The detection limits for dichlorvos were 1 μM for a flow-injection mode and 0·2 μM for stationary measurement. The AChE acetylthiocholine-hexacyanoferrate(III) system opens up possibilities for the detection and assay of toxic chemicals by the use not only potentiometric but also of other types of sensors.

Original languageEnglish
Pages (from-to)569-576
Number of pages8
JournalBiosensors and Bioelectronics
Issue number8
StatePublished - 1994


FundersFunder number
Centerf or Absorption in Science
Wolfson Family Charitable Trust


    • acetylcholinesterase
    • potentiometric biosensor
    • toxic detection


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