Photoelectrochemical label-free immunoassay of octachlorostyrene based on heterogeneous CdSe/CdS/Pt/TiO2 nanotube array

• A novel heterogeneous CdSe/CdS/Pt/TiO2 NTA were prepared and characterized.
• The CdSe/CdS/Pt/TiO2 NTA photoelectrode was used for OCS PEC immunoassay.
• The proposed immunosensor owns high sensitivity, specificity for OCS assay in sewage sample.

A novel heterogeneous CdSe/CdS/Pt/TiO2 nanotube array photoelectrode (denoted as CdSe/CdS/Pt/TiO2 NTA) was developed by dipping and deposition technique as well as successive ionic layer adsorption and reaction (SILAR). An octachlorostyrene (OCS) photoelectrochemical immunosensor was constructed by cross-linking anti-OCS antibody onto the CdSe/CdS/Pt/TiO2 NTA using anti-OCS antibody prepared in this laboratory. The as-prepared photoelectrochemical immunosensor is highly stable, sensitive and selective to octachlorostyrene with a limit of detection (LOD) of 2.08 pM and a linear range from 0.1 to 10 μM. The practical application of the photoelectrochemical immunosensor is also realized in the selective determination of octachlorostyrene in sewage sample.