A novel immobilization matrix for the biosensing of phenol: self assembled monolayers of calixarenes

Aim: The development of calixarene based phenol biosensor. Methods: This study describes the application of a calixarene derivative, 5,17-diamino-25,27-bis(3-thiol-1- oxypropane)-26,28-dihydroxycalix[4] arene (HS-Calix-NH2) which has both amino and thiol functionalities, in the practical surface modifications for biomolecule binding. The structure of HS-Calix-NH2 allows easy interaction with Au surface and one-step biomolecule immobilization. Self-assembled monolayers (SAMs) of p-amino-functionalized mercaptoalkylcalixarene (HS-Calix-NH2) were formed onto the Au electrode. Then, Laccase (Lac) enzyme was immobilized onto the modified surface by crosslinking with glutaraldehyde (GA). Resulted electrode (HS-Calix-NH2/Lac) was used for the electrochemical analysis of phenolic compounds at -50 mV. Results: The linearity was observed in the range of 0.1-100 mu M and 1.0-100 mu M for catechol and phenol, respectively. The potential use of the biosensor was investigated for phenol analysis in artificial samples which simulate the industrial waste water, which is highly acidic and composed of concentrated salt, without needing any sample pre-treatment step. Conclusion: The prepared Lac biosensor has a potential for rapid, selective and easy detection of phenolic contaminations in samples.