A team of researchers has developed a new microfluidic paper-based analytical device (μPAD) that combines electrochemical and colorimetric detection to enable high sensitivity and specificity in the simultaneous detection of lead, cadmium, and copper. Although a bismuth-modified electrode can increase the sensitivity of lead and cadmium detection, its use in copper detection is limited because the bismuth signal overlaps with the signal for copper. In the new method, the μPAD is divided into two parts, with the first part utilizing a bismuth-modified boron-doped diamond electrode (Bi-BDDE) for electrochemical detection of lead and cadmium. The limit of detection for both metals was 0.1 ng mL-1. The second part uses colorimetric detection based on the catalytic etching of silver nanoplates (AgNPls) by thiosulfate (S2O32-) for the detection of copper. The color of AgNPls on μPAD changes from pinkish-violet to colorless upon the addition of copper, which can be monitored by naked eyes, and its detection limit was 5.0 ng mL-1 by Image J analysis. The new method was applied to the simultaneous determination of these three metals in real samples, and no significant differences in accuracy and precision were observed compared to the standard method. The researchers suggest that the new method is cost-effective and simple, and can be used for food and environmental analysis.