Label‐free Immunosensor for the Determination of Microcystin‐LR in Water

Abstract This paper describes the development of a label‐free electrochemical immunosensor based on polyethyleneimine‐stabilized magnetite nanoparticles (MGNnP‐PEI) for the determination of microcystin‐LR (MC‐LR). MGNnP‐PEI was immobilized on the glassy carbon electrode (GCE) surface and employed as a platform for anchorage of the anti‐MC‐LR. Hydroquinone in solution was used as a redox probe. After optimization, the immunosensor exhibited a linear response to MC‐LR concentrations in the range of 0.1 to 500 ng mL −1 with a calculated detection limit of 0.053 ng mL −1 . The immunosensor was satisfactorily applied in the quantification of MC‐LR in a water sample collected from a freshwater lagoon.