Quantitative colorimetric paper analytical devices based on radial distance measurements for aqueous metal determination.

Here we report a new microfluidic paper-based analytical device (mPAD) for quantifying metals in water. Metals represent an important class of water contaminants that come from a variety of sources including mining, transportation, manufacturing, waste management, and energy production. Current technologies for quantifying aquatic metals in water are expensive, relatively slow, tedious, provide inadequate performance, and are difficult to use in a field setting.