New Electrochemical Sensors Based on Clay and Carbon Micro and Nanoparticles for Pharmaceutical and Environmental Analysis

A. Maghear, A. Cernat, C. Cristea, A. Marian, I.O. Marian, R. Săndulescu
Iuliu Hatieganu University of Medicine and Pharmacy, RO

Keywords: montmorillonite, clay-modified electrodes, MWCNTs, biosensors, pharmaceuticals


New composite materials based on clay micro and nanoparticles, MWCNTs and polymeric films for the development of electrochemical sensors and biosensors have been realized. Particle size separation of two Romanian bentonites from Răzoare and Valea Chioarului deposits was made by sedimentation, decantation, centrifugation and ultracentrifugation. The physico-chemical characterization established the nature and properties of the investigated clays, revealing the characteristics of the montmorillonite, their main component. The electrochemical behavior of acetaminophen, ascorbic acid and riboflavin phosphate was tested on clay-modified carbon paste electrodes with different clay particle sizes using CV. The development of composite electrodes for the construction of biosensors based on HRP immobilization in a polyetylenimine and clay porous gel film for acetaminophen detection was successfully realized. Glassy carbon electrodes modified with clay and PEI or polypyrrole films were also tested for the trace metal analysis using CV and SWV with good results. In order to realize a nitrate reductase biosensor, polypyrrole films, polystyrene spheres and carboxylated MWCNTs were deposed on graphite electrodes of 1 mm2 surface to increase the electroconductivity of the polymeric film and to ensure the immobilization of the enzyme. The resulting structures were characterized by microscopy,AFM and Raman.