Miniaturized on-chip electromembrane extraction with QR code-based red-green-blue analysis using a customized Android application for copper determination in environmental and food samples.

A miniaturized on-chip electromembrane extraction device with QR code-based red-green-blue analysis was designed to determine copper in water, food, and soil. The acceptor droplet consisted of ascorbic acid as the reducing agent and bathocuproine as the chromogenic reagent. The formation of a yellowish-orange complex was a sign of copper in the sample.