title: Separation-free electrochemical immunosensor for rapid determination of atrazine.
abstract: A separation-free electrochemical immunoassay method for the detection of the pesticide atrazine is described. The method developed is a competitive ELISA incorporating disposable screen printed horseradish peroxidase modified electrodes as the detector element in conjunction with single-use atrazine immuno-membranes. Screen printed carbon electrodes were prepared using carbon ink incorporating horseradish peroxidase. A monoclonal antibody for atrazine was immobilised onto Biodyne C membranes which were, in turn, placed over the electrode surface. The assay was based on competition for available binding sites between free atrazine and an atrazine-glucose oxidase conjugate prepared 'in-house'. In the presence of glucose, H2O2 formed by the conjugate was reduced by enzyme-channelling via the HRP electrode. The HRP was in turn re-reduced by a direct electron transfer mechanism at a potential of +50 mV Vs Ag/AgCl. Any H2O2 formed in the bulk solution by unbound atrazine-GOD conjugate was scavenged by excess catalase thus removing the requirement for a washing step. The performance of the method was compared with a commercial immunoassay kit for atrazine.
authors.affiliation: Department of Clinical Biochemistry, Medical School, University of Newcastle Upon Tyne, UK.
authors.forename: R W
authors.initials: RW
authors.lastname: Keay
authors.forename: C J
authors.initials: CJ
authors.lastname: McNeil
mesh_terms: D000911:Antibodies, Monoclonal; D001280:Atrazine / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004563:Electrochemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005949:Glucose Oxidase; D006540:Herbicides / Q000032:analysis* / Q000276:immunology; D006735:Horseradish Peroxidase; D006861:Hydrogen Peroxide
chemical_list: D000911:Antibodies, Monoclonal; D006540:Herbicides; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D001280:Atrazine