A colorimetric chemosensor for sensitive and selective detection of copper(ii) ions based on catalytic oxidation of 1-naphthylamine

Abstract

Rapid on-site detection of copper(II) ions (Cu²⁺) with high sensitivity and selectivity is of great significance in the safety monitoring of drinking water and food. Colorimetric detection is a robust fast determination method with the main drawback of low sensitivity. Herein, we developed a colorimetric chemosensor based on a colored polymer product. Via a Cu–Fenton mechanism, 1-naphthylamine (α-NA) was oxidized by H₂O₂ and brownish-red poly(1-naphthylamine) (PNA) was produced. The obtained Cu²⁺ sensor showed a linear response from 0.05 μM to 7 μM, with a detection limit of 62 nM. Our findings expanded chromogenic reaction types for colorimetric detection.