Abstract

A simple and highly selective colorimetric sensor for Cu²⁺ is fabricated in this work based on the Cu²⁺-induced self-aggregation of gold nanoparticles (GNPs). In this new design, GNPs are first functionalized with cysteamine molecules on their surface through the well-known strong Au-S interaction. Then salicylaldehyde is introduced to link with the cysteamine through a simple Schiff’s base reaction. Since the Schiff’s bases formed on the GNPs surface may serve as efficient and selective complexing reagents for Cu²⁺, Cu²⁺ can specifically react with the Schiff’s base complexes and thus result in the self-assembly of GNPs accompanied with color changes. Therefore, a facile and low-cost colorimetric sensor for visual detection of Cu²⁺ was developed without requirement of any instrument.

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