Analysis of phosphorothionate pesticides using a chloroperoxidase pretreatment and acetylcholinesterase biosensor detection

Clarisse B S Roepcke, Susanne B Muench, Holger Schulze, Till T Bachmann, Rolf D Schmid, Bernhard Hauer

Research output: Contribution to journalArticlepeer-review

Abstract

Acetylcholinesterase (AChE) is responsible for the hydrolysis of acetylcholine in the nervous system. It is inhibited by organophosphate and carbamate pesticides. However, this enzyme is only slightly inhibited by organophosphorothionates, which makes the detection of these pesticides analytically very difficult. A new enzymatic method for the activation and detection of phosphorothionates was developed with the capability to be used directly in food samples without the need of laborious solvent extraction steps. Chloroperoxidase (CPO) from Caldariomyces fumago was combined with tert-butyl hydroperoxide and two halides. Chlorpyrifos and triazophos were completely oxidized. Fenitrothion, methidathion and parathion methyl showed conversion rates between 54 and 61%. Furthermore, the oxidized solution was submitted to an AChE biosensor assay. Chlorpyrifos spiked in organic orange juice was oxidized, where its oxon product was detected in concentrations down to 5 microg/L (final concentration food sample: 25 microg/L). The complete duration of the method takes about 2 h.
Original languageEnglish
Pages (from-to)8748-56
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume58
Issue number15
DOIs
Publication statusPublished - 2010

Keywords

  • Acetylcholinesterase
  • Biosensing Techniques
  • Chloride Peroxidase
  • Enzymes, Immobilized
  • Food Contamination
  • Organophosphorus Compounds
  • Pesticides

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