Development of an electrochemical chemosensor for the rapid detection of zinc based on air stable lipid films with incorporated calix4arene phosphoryl receptor

Abstract

This work describes the preparation of a selective receptor for the rapid, selective, and sensitive electrochemical flow injection analysis of zinc using air stable lipid films supported on a methacrylate polymer on a glass fibre filter with incorporated artificial receptor. The selective receptor was synthesised by transformation of the –OH groups of resorcin4arene receptor into phosphoryl groups. These lipid films were supported on a methylacrylate polymer (i.e. methacrylic acid was the functional monomer for the polymerisation, ethylene glycol dimethacrylate was used as the crosslinker and 2,2′-azobis-2-methylpropionitrile as an initiator). A minisensor device was constructed for the electrochemical flow injection analysis of zinc based on air stabilised lipid films supported on a polymer. The device can sense the analyte in a drop (75 µL) of sample. Zinc was injected into flowing streams of a carrier electrolyte solution. A complex formation between the calix4arene phosphoryl receptor and zinc takes place. This enhances the pre-concentration of zinc at the lipid membrane surface which in turn causes dynamic alterations of the electrostatic fields and phase structure of membranes; as a result ion current transients were obtained and the magnitude of these signals was correlated to the substrate concentration. The response times were ca 5 s and zinc was determined at concentration levels of nanomolar. The analytical curve was linear in the concentration range 1.00 × 10−7 − 1.20 × 10−6 M with detection limit of 5.00 × 10−8 M and a relative standard deviation lower than 4%. The effect of potent interferences included a wide range of other metals. As an analytical demonstration, trace concentrations of Zn(II) were successfully detected in real samples of waters without any laborious and time-consuming treatment.