title: Development of an electrochemical biosensor for the detection of aflatoxin M1 in milk.
abstract: We have developed an electrochemical immunosensor for the detection of ultratrace amounts of aflatoxin M(1) (AFM(1)) in food products. The sensor was based on a competitive immunoassay using horseradish peroxidase (HRP) as a tag. Magnetic nanoparticles coated with antibody (anti-AFM(1)) were used to separate the bound and unbound fractions. The samples containing AFM(1) were incubated with a fixed amount of antibody and tracer [AFM(1) linked to HRP (conjugate)] until the system reached equilibrium. Competition occurs between the antigen (AFM(1)) and the conjugate for the antibody. Then, the mixture was deposited on the surface of screen-printed carbon electrodes, and the mediator [5-methylphenazinium methyl sulphate (MPMS)] was added. The enzymatic response was measured amperometrically. A standard range (0, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.3, 0.4 and 0.5 ppb) of AFM(1)-contaminated milk from the ELISA kit was used to obtain a standard curve for AFM(1). To test the detection sensitivity of our sensor, samples of commercial milk were supplemented at 0.01, 0.025, 0.05 or 0.1 ppb with AFM(1). Our immunosensor has a low detection limit (0.01 ppb), which is under the recommended level of AFM(1) [0.05 μg L-1 (ppb)], and has good reproducibility.
authors.affiliation: Laboratoire IMAGES EA 4218, Bâtiments S, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan Cedex, France. nathalie.paniel@univ-perp.fr
authors.forename: Nathalie
authors.initials: N
authors.lastname: Paniel
authors.forename: Antonio
authors.initials: A
authors.lastname: Radoi
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marty
mesh_terms: D016607:Aflatoxin M1 / Q000032:analysis*; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D008892:Milk / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D016607:Aflatoxin M1