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Lab on paper: iodometric titration on a printed card
Nicholas M Myers1, Emalee N Kernisan2, Marya Lieberman1
1†Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Analytical Chemistry
|February 26, 2015
Summary
A novel paper test card enables on-demand iodometric titration for quantifying iodine in salt and detecting substandard antibiotics. This low-resource diagnostic tool offers accurate results, improving accessibility to essential chemical analyses.
Area of Science:
- Analytical Chemistry
- Materials Science
Background:
- Traditional iodometric titrations require specialized laboratory equipment and trained personnel.
- Reagent incompatibility and on-demand mixing pose significant challenges for developing portable analytical devices.
Purpose of the Study:
- To engineer a paper-based test card for on-demand iodometric titration.
- To validate the test card's performance for quantifying iodine in aqueous solutions and detecting substandard beta-lactam antibiotics.
- To assess the device's suitability for low-resource settings.
Main Methods:
- Development of a paper test card incorporating a surface-tension-enabled mixing (STEM) mechanism for dried, incompatible reagents.
- Quantification of iodine from iodate in aqueous solutions using the paper test card.
- Validation of the test card's accuracy and precision with and without image processing software.
- Detection of substandard amoxicillin using iodometric back-titration on the paper card.
Main Results:
- The paper test card accurately quantifies 0.8-15 ppm of iodine with an initial accuracy of 1.4 ppm I and precision of 0.9 ppm I.
- Image processing software improved accuracy and precision to 0.9 ppm I.
- The card effectively distinguishes amoxicillin solutions differing by 0.15 mg/mL within a 0-0.9 mg/mL range.
Conclusions:
- The engineered paper test card offers a viable, low-cost solution for on-demand iodometric titrations.
- The device meets the World Health Organization ASSURED criteria, making it suitable for resource-limited environments.
- This technology has potential applications in food safety (iodine fortification) and pharmaceutical quality control (antibiotic detection).
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