Preparation of urease/nano-structured polyaniline-Nafion®/Au/Al2O3 electrode for inhibitive detection of mercury ion

Highly selective colorimetric sensing of Cu2+ using a Schiff base derivative immobilized on polyvinyl alcohol microspheres

PVA-SH microspheres could selectively detect Cu²⁺ by visible color change.

Enzymatic electrochemical biosensor for urea with a polyaniline grafted conducting hydrogel composite modified electrode

A new conducting polymer hydrogel (CPH) comprising polyaniline grafted polyvinyl alcohol–polyacrylamide ensured high enzyme loading and urea sensitivity.

Indirect determination of mercury ion by inhibition of a glucose biosensor based on ZnO nanorods

A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 × 10⁻⁶ mM to 0.5 × 10⁻⁴ mM, and from 0.5 × 10⁻⁴ mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10⁻³ mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.