Digital microfluidic-based fluorescence methods for the automated determination of copper ions in wine

A novel approach is introduced by combining digital microfluidic technology with click chemistry for automated sample handling on a chip, enabling accurate detection of copper ions in wine. By developing a copper-catalyzed click chemistry reaction using azide coumarin and hexanol, we have introduced a method that offers advantages such as simplicity, minimal by-products, and enhanced resistance to interference compared with other fluorescent methods. Furthermore, optimization of the digital microfluidic chip parameters enabled processing of sub-microliter samples with a droplet coefficient of variation of 0.6%, outperforming the ~ 4.0% error typically seen with conventional pipetting methods. This method processes samples as small as 870 nL, providing cost efficiency, automated detection, reduced errors, and a detection limit of 15.4 μM (0.98 mg/L), meeting testing requirements. Our approach effectively detects copper ion contamination in wine with a recovery of 98.7 to 106%, offering robust technical support for food safety regulations.