Highly sensitive electrochemical detection of the marine toxins okadaic acid and domoic acid with carbon black modified screen printed electrodes

A novel electrochemical immunosensor for the detection of important marine biotoxins domoic acid (DA) and okadaic (OA) was developed. The sensors used carbon black modified screen-printed electrodes (CB-SPE) obtained using a high-throughput method. performance stability CB SPEs bare (c-SPEs) were compared cyclic voltammetry impedance spectroscopy. CB-SPEs showed improved long-term (at least six months) electro-catalytic properties with c-SPEs. bio-functionalized DA or OA protein-conjugates to develop two indirect competitive immunosensors differential pulse (DPV). DPV signals fitted well four-parameter dose-response curves (R2 > 0.98) excellent LODs (LOD = 1.7 ng mL?1 in buffer; LOD 1.9 mussel extract; 0.15 0.18 extract). No significant interference naturally co-occurring toxins saxitoxin, tetrodotoxin detected immunosensor. Similarly, did not cross-react very limited observed dinophysis DTX-1, DTX-2 DTX-3 (OA congeners). Moreover, both remained stable after at 25 days storage 4 °C. This work demonstrates potential affordable, mass-produced nanomaterial-modified toxin shellfish.