A New Disposable Biosensor for the Accurate and Sensitive Detection of Ethylenebis(Dithiocarbamate) Fungicides

ABSTRACT

A disposable bienzymic sensor for the reliable determination of dithiocarbamate fungicides was developed. Aldehyde dehydrogenase and a highly stable NADH oxidase were immobilized on the surface of a disposable Pt-sputtered carbon paste screen printed electrode by using photocrosslinkable poly(vinylalcohol) bearing styrylpyridinium groups. Due to the very poor solubility of ethylenebis(dithiocarbamates), a preliminary transformation of these compounds in a highly soluble sodium form was carried out using EDTA, disodium form. The advantages of performing this previous step was both to solubilize the compounds and to use a commercial disodium ethylenebis(dithiocarbamate), i.e. nabam, as calibration compound. The sensor was used for the determination of EDTA/Na₂-transformed zineb and the results showed a good correlation with those achieved with nabam. As low as 8 ppb of pesticide has been detected in these first experiments, whereas the detection limit of the recommended spectrophotometric method is about 400 ppm.

Keywords::

• biosensor
• disposable
• inhibition
• ethylenebis(dithiocarbamate)
• fungicides
• nabam
• aldehyde dehydrogenase
• NADH oxidase
• entrapment