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Renewable magnetic ion-selective colorimetric microsensors based on surface modified polystyrene beads
Sutasinee Apichai1, Lu Wang2, Kate Grudpan3
1Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211, Geneva, Switzerland; Center of Excellence for Innovation in Analytical Science and Technology, Chiang Mai University, Chiang Mai, 50200, Thailand; Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.
New magnetic ion-selective microspheres enable colorimetric sensing of potassium ions (K+). These novel microsensors offer rapid and selective detection, utilizing magnetic collection for enhanced observation.
Area of Science:
- Materials Science
- Analytical Chemistry
- Nanotechnology
Background:
- Development of ion-selective sensors is crucial for chemical analysis.
- Optode sensing typically involves complex setups and lacks magnetic manipulability.
- Novel materials are needed for efficient and selective ion detection.
Purpose of the Study:
- To develop novel magnetic ion-selective colorimetric microspheres for sensing applications.
- To functionalize polystyrene beads with key optode components and magnetic nanoparticles.
- To evaluate the performance of these microsensors for potassium ion (K+) detection.
Main Methods:
- Surface modification of polystyrene beads (0.8 μm) with chromoionophore, ion-exchanger, and ionophore.
- Adsorption of magnetic nanoparticles onto the modified beads using a mixed solvent method.
- Characterization of microsphere size using dynamic light scattering.
- Colorimetric detection based on hue signal extraction from digital images.
- Magnetic accumulation of microsensors for enhanced observation.
Main Results:
- Successfully synthesized magnetic ion-selective colorimetric microspheres with an average diameter of 0.79 ± 0.06 μm.
- Demonstrated reversible microsensor response to K+ over a concentration range of 10⁻⁶ M to 10⁻² M.
- Achieved excellent selectivity for K+.
- Obtained a rapid response time (t99 < 2.6 ± 0.5 min) for concentrations above 10⁻⁵ M.
- Found that solvatochromic dyes were not successful as pH-independent transducers in this system.
Conclusions:
- The developed magnetic microspheres represent a novel platform for ion-selective colorimetric sensing.
- The magnetic properties facilitate efficient handling and observation, enhancing usability.
- These microsensors show promising performance for selective and rapid K+ detection.
