Design of an integrated microfluidic paper-based chip and inspection machine for the detection of mercury in food with silver nanoparticles

For most of the fast screening test papers for detecting Hg²⁺, the obtained results are qualitative. This study developed an operation for the µPAD and combined it with the chemical colorimetric method. Silver nanoparticle (AgNP) colloids were adopted as the reactive color reagent to combine and react with the Hg standards on the paper-based chip. Then, the RGB values for the color change were used to establish the standard curve (R² > 0.99). Subsequently, this detection system was employed for the detection tests of actual samples, and the detected RGB values of the samples were substituted back to the formula to calculate the Hg²⁺ contents in the food. In this study, the Hg²⁺ content and recovery rate in commercially available packaged water and edible salts were measured. The research results indicate that a swift, economical, and simple detection method for Hg²⁺ content in food has been successfully developed.