Colorimetric detection of solution concentration based on a paper-based microfluidic device

摘要： A new method for colorimetric detection of solution concentration is presented. A paper-based micro?uidic device was designed and made using printed circuit board technology. Detection zone patterns were designed and transferred to a printed circuit board by hollowing technology. The printed circuit board with patterns was stuck onto a copper sheet. The hollowed zone was ?lled with solid para?n and then covered with a piece of ?lter paper. The para?n wax was melted by heating the copper sheet and permeated into the ?lter paper. Solution to be detected was pipetted on the paper-based device with detective zones. The images of the detective zones were obtained using a microscope with charge-coupled device, which is used for calculating RGBI model to further obtain the solution concentration. Litmus was demonstrated in sample experiments. Results showed that maximum error of measured value of solution concentration to its true value is less than 2% using the presented method.