Abstract
This paper describes new-label free immunoassays for the detection of atrazine using optical Surface Plasmon Resonance (SPR) and Electrochemical Impedance Spectroscopy (EIS) by employing gold functionalised with self-assembled mixed monolayer. The mixed monolayer, formed by 16-mercaptohexadecanoic acid (MHDA) and biotinyl-PE, is used as the basic layer in the fabrication of the immunoprobe. The interfacial interaction of a biotinyl-Fab fragment K47 antibody with the mixed monolayer is based on a biotin-avidin system using the neutravidin molecule. Thus, in this study the multilayer engineering is mentored by SPR and EIS methods. In addition, the specificity and sensitivity of this self-assembled multilayer system to the presence of atrazine are investigated. The limit detection of Atrazine obtained with EIS technique is equal to 20 ng/ml and with SPR technique is equal to 50 ng/ml. (c) 2007 Elsevier B.V. All rights reserved.