Microfluidic paper-based device integrated with smartphone for point-of-use colorimetric monitoring of water quality index

The measurements by lab-on-a-chip devices are very interesting regarding the reduction of reagents, time and cost. In this paper, we have described the construction and application of a new device based on colorimetric measurements using a smartphone camera and a microfluidic paper-based device (μPAD), both fixed in supports obtained through 3D printing, employing a polylactic acid filament. The μPAD was evaluated as a water quality index device by colorimetric monitoring of water hardness (Ca2+ and Mg2+), total phenols (catechol), and pH. Under optimized parameters, the proposed method presented a linear range between 20 and 560 mg L−1 for Ca2+ and Mg2+(hardness), 0.20 to 16 mg L−1 of catechol and pH from 4.7 to 12, and limits of detection of 0.083 mg L−1, 0.124 mg L−1 and 0.262, for water hardness, catechol, and pH, respectively. The proposed device was successfully applied for the quality monitoring of the distribution of water samples.