Disposable Screen-Printed pH-Electrode for Determination of Anticholinesterase Activity

Plastic, fully screen-printed, disposable pH sensors based on ruthenium dioxide are described. Application of thick-film technology resulted in cheap and highly reproducible fabrication of the sensors. The electrodes enable fast and selective measurements, with good sensitivity, in acidic and neutral range of pH. The possibility of monitoring pH changes caused by enzymatic processes make them useful as transducers in pH-based biosensors. Moreover, the surface of carbon electrodes doped with ruthenium dioxide offer a good support for enzyme adsorption. These electrodes with immobilised acetylcholinesterase can be used for determination of some enzymatic inhibitors. The biosensors enable easy and fast detection of carbofuran at the sub-ppb level. Only a few minutes are required for pesticide determination, including the biosensor incubation in a sample. Other anticholinesterase active substances, which belong to the group of carbamates and phosphoorganic compounds might be determined in similar way