First electrochemical immunosensor for the rapid detection of mustard seeds in plant food extracts.

This paper describes the first biosensor reported to date for the determination of mustard seed traces. The biosensor consists of an amperometric immunosensing platform able to sensitively and selectively determine Sin a 1 content, the major allergen of yellow mustard and the most abundant protein of these seeds. The immunosensing platform exploits the coupling of magnetic microbeads (MBs) modified with sandwich-type immune complexes, comprising polyclonal and monoclonal antibodies, selective to the target protein for its capturing and detection, respectively. In addition, a HRP-conjugated secondary antibody was used for enzymatic labelling of the monoclonal antibody, and amperometric transduction was made at screen-printed carbon electrodes (SPCEs) using the hydroquinone (HQ)/H 2 O 2 system. The electrochemical immunosensor allows the simple and fast detection (a single 1-h incubation step) of Sin a 1 with a limit of detection of 0.82 ng mL−1 (20.5 pg of protein in 25 μL of sample) with high selectivity against structurally similar non-target allergenic proteins (such as Pin p 1 from pine nut). The developed immunoplatform was successfully used for the analysis of peanut, rapeseed, cashew, pine nut and yellow mustard extracts, giving only positive response for the yellow mustard extract with a Sin a 1 content, in full agreement with that provided by conventional ELISA methodology. First electrochemical bioplatform of mustard seeds through sensitive and selective amperometric determination of Sin a 1. Image 1 • First biosensor reported to date for the determination of mustard seed traces. • Amperometric determination of Sin a 1, the major allergen of yellow mustard seeds. • Sandwich immunosensing platform based on MBs and SPCEs. • Sensitive (LOD of 0.82 ng mL−1 for Sin a 1 standards) and selective determination. • Accurate determination in plant food extracts. [ABSTRACT FROM AUTHOR]