Paper analytical instruments are used to promote research in environments where laboratory reagents, instrumentation, and glassware are not available. Paper analytical instruments are designed to do things like separate fluids from cells or particulates, store reagents, and serve as timers (Myers et al. 3764). The paper test card was created for the experiment to perform iodometric titration, which is an application that requires storage as well as the mixing of multiple mutually incompatible reagents on request. Titration begins when the consumer applies a test solution to a test card. Dried reagents are reconstituted before being mixed using the STEM mechanism. The device is able to quantify 0.8 to 15 ppm of atoms of the iodine from aqueous solution of iodate. It can be applied in quantifying levels of iodine in fortified salt. During the experiment, an accuracy of 1.4 ppm I as well as a 0.9 ppm I precision was obtained by blinded internal lab validation when newly trained users read test card. However, precision and accuracy improved greatly to 0.9 ppm I, when computer software was used to process images. Out of 110 cards, four of them showed discrepancy reading due to errors of fabrication (Myers et al. 3767).
Similarly, paper card is able to identify substandard beta-lactam antibiotics by using iodometric back-titration. Using paper test card to quantify amoxicillin led to good distinction between solutions that had difference of 0.15 mg/mL, with 0 to 0.9 mg/mL working range. The test card was actually designed in a bid to meet the ASSURED criteria of WHO to use in low resource conditions, when laboratory-based procedures are often unavailable (Myers et al. 3768).
Myers, Nicholas M., Emalee N. Kernisan, and Marya Lieberman. “Lab on Paper: Iodometric Titration on a Printed Card.” Analytical Chemistry, vol. 87, no. 7, 2015, pp. 3764-3770.