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. Then, the qualitative and quantitative analysis of the dried acceptor droplet was done by the customized Android app that was developed based on image analysis concepts. In this appli-cation, principal component analysis was performed on the data for the first time to reduce the three dimensions, red, green, and blue, to one dimension. The effective extraction parameters were optimized. The limit of detection and limit of quantification were 0.1 mu g mL-1. Intra-and inter-assay relative standard deviations ranged between 2.0 and 2.3 % and 3.1-3.7 %, respectively. The calibration range was studied between 0.1 and 25 mu g mL-1 (R2 = 0.9814).

Automated summary

A miniaturized on-chip electromembrane extraction device with QR code-based red-green-blue analysis was developed 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 dried acceptor droplet was analyzed qualitatively and quantitatively using a customized Android app based on image analysis concepts. The optimized device showed a limit of detection and limit of quantification of 0.1 μg/mL, with relative standard deviations ranging from 2.0% to 2.3% and 3.1% to 3.7% for intra- and inter-assay measurements, respectively. The calibration range was studied between 0.1 and 25 μg/mL (R2 = 0.9814).