# A Facile Fluorescent Visualization Method Based on Copper Clusters for Formaldehyde Detection

## TL;DR

This paper introduces a simple and effective method using copper clusters to visually detect formaldehyde, useful for environmental monitoring.

## Contribution

A green, one-step method to synthesize copper clusters for visual formaldehyde detection with enhanced portability via hydrogel immobilization.

## Key findings

- Copper clusters showed stable red fluorescence that quenches in the presence of formaldehyde.
- The method was successfully applied to detect formaldehyde in air samples.
- Immobilizing clusters in hydrogels improved detection performance and portability.

## Abstract

Establishing a simple and effective method for the visual detection of formaldehyde plays an important role in environmental emergency monitoring. In this work, L-cysteine-stabilized copper clusters were synthesized via a green, mild, and facile one-step preparation method. Through the optimization of reaction conditions, including reactant concentration and pH, the clusters exhibited stable red fluorescence. Upon exposure to formaldehyde, the fluorescence intensity of copper clusters gradually quenched with increasing formaldehyde concentration, enabling the development of a visual detection method that was successfully applied to analyze formaldehyde samples in air. Furthermore, by immobilizing the copper clusters into hydrogels, the visual detection performance and portability of the material were significantly enhanced. This method offers the advantages of simple preparation and rapid and accurate determination, demonstrating potential for semi-quantitative field detection of formaldehyde in emergency scenarios.