A NH2-MWCNTs/Chitosan Nanocomposite Film-Based Electrochemical Immunosensor for Sensitive Detection of 1-Aminopyrene in Seawater

1-Aminopyrene, as a transformation product of the priority pollutant 1-nitropyrene, has raised increasing concerns due to its carcinogenic, mutagenic, and bioaccumulative properties in marine environments. A rapid and sensitive method for trace 1-aminopyrene detection in seawater is essential for marine environmental monitoring and public health protection. In this paper, a novel electrochemical immunosensor was fabricated based on an NH2-functionalized multi-walled carbon nanotubes-chitosan (NH2-MWCNTs/CS) nanocomposite film loaded with anti-1-aminopyrene antibody on a glassy carbon electrode. The NH2-MWCNTs/CS composite served as a conductive and biocompatible matrix that facilitated interfacial electron transfer and provided a suitable surface for adsorption-based antibody immobilization. Potassium ferricyanide was employed as an electrochemical probe to generate voltammetric signals, and the immune response was investigated by differential pulse voltammetry. Under optimized experimental conditions, the peak current change was inversely proportional to the 1-aminopyrene concentration in the range of 0.5 ng·mL−1 to 110 ng·mL−1, with a detection limit of 0.36 ng·mL−1. The immunosensor demonstrated good selectivity, stability, and anti-interference capability in complex sample matrices. It was successfully applied to the determination of 1-aminopyrene in real seawater samples, with recovery rates ranging from 97.53% to 99.30% and relative standard deviations below 0.92%. The results indicate that the proposed immunosensor offers a simple, cost-effective, and environmentally friendly alternative to conventional chromatographic methods, and holds great potential for on-site monitoring of trace PAH metabolites in marine environments.