Disposable competitive-type immunoassay for determination of aflatoxin B1 via detection of copper ions released from Cu-apatite

A disposable electrochemical immunosensor was developed for detection of aflatoxin B1 (AFB1) based on stripping voltammetric detection of copper ions released from Cu-apatite. AFB1 antibody (Ab) was firstly fixed on the gold nanoparticle (Au NPs) modified screen-printed carbon electrode (SPCE). AFB1-bovine serum albumin (AFB1-BSA) conjugate was labeled with Cu-apatite, and then competed with AFB1 for binding to the Ab. Copper ions were released from Cu-apatite through acidolysis and stripping voltammetry signal of the copper ions was used for the detection. The Cu-apatite increased the amount of loaded copper ions, and the anodic stripping strategy performed in the micro electrolytic cell of the SPCE simplified the detection procedure and further amplified the electrochemical signal. This immunosensor could detect AFB1 over a wide concentration range from 0.001 to 100 ng mL(-1) with a detection limit of 0.2 pg mL(-1). The low cost, high sensitive, rapid and accurate method may find widely potential application in the detection of other toxic or harmful substances. (C) 2015 Elsevier B.V. All rights reserved.