Rabid detection of chloride ions in fresh concrete using a chromium-free paper-based analytical device (μPAD)

Abstract

This study successfully developed a chromium-free paper-based analytical device (μPAD) for chloride detection in fresh concrete. The sensing materials were chemically synthesized and coated to the paper through drop casting. The fabricated μPAD was thoroughly tested with various concentrations of chloride ions. Upon interaction with the μPAD, the chloride ions in the solution react with a chromium-free silver compound, exhibiting a specific coloring height proportional to the absolute chloride concentration. The height of the color change during a reaction can vary based on the chloride concentration, which allows for predicting the chloride concentration in a solution. The results reveal that μPAD has extraordinary precision in identifying chloride in fresh concrete, which highlights its immense potential for future applications.