title: Lab on paper: iodometric titration on a printed card.
abstract: A paper test card has been engineered to perform an iodometric titration, an application that requires storage and mixing on demand of several mutually incompatible reagents. The titration is activated when a user applies a test solution to the test card: the dried reagents are reconstituted and combined through a surface-tension-enabled mixing (STEM) mechanism. The device quantifies 0.8-15 ppm of iodine atoms from iodate in aqueous solutions. This is useful, for example, to quantify iodine levels in fortified salt. A blinded internal laboratory validation established the accuracy as 1.4 ppm I and the precision as 0.9 ppm I when the test card was read by newly trained users. Using computer software to process images, the accuracy and precision both improved to 0.9 ppm I. The paper card can also detect substandard β lactam antibiotics using an iodometric back-titration. When used to quantify amoxicillin, good distinction is achieved between solutions that differ by 0.15 mg/mL over a working range of 0-0.9 mg/mL. The test card was designed to meet the World Health Organization ASSURED criteria for use in low resource settings, where laboratory-based analytical procedures are often not available.
authors.affiliation: †Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Myers
authors.affiliation: ‡University of Toledo, Toledo, Ohio 43606, United States.
authors.forename: Emalee N
authors.initials: EN
authors.lastname: Kernisan
authors.affiliation: †Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
authors.forename: Marya
authors.initials: M
authors.lastname: Lieberman
mesh_terms: D007455:Iodine / Q000032:analysis*; D007753:Laboratories; D010209:Paper; D011327:Printing; D015203:Reproducibility of Results; D013500:Surface Tension; D017186:Titrimetry / Q000295:instrumentation* / Q000379:methods*; D014944:World Health Organization
chemical_list: D007455:Iodine