Highly sensitive and selective fluoride ion sensors based on microcantilevers modified with hydrogels

Area of Science:

• Chemical Sensors
• Materials Science
• Environmental Monitoring

Background:

• Fluoride ion (F-) detection is crucial for environmental and health monitoring.
• Existing methods for fluoride detection can be complex or lack sensitivity.
• Microcantilever sensors offer a promising platform for sensitive and selective chemical detection.

Purpose of the Study:

• To develop and characterize two novel microcantilever sensors for sensitive and selective fluoride ion detection.
• To investigate the mechanism of fluoride ion interaction with modified hydrogels on microcantilevers.
• To evaluate the performance of the sensors in terms of detection limits and selectivity against common interfering ions.

Main Methods:

• Fabrication of microcantilever sensors modified with chitosan/gelatin hydrogels doped with CH3(OCH2CH2)3OTBDPS.
• Fabrication of microcantilever sensors modified with chitosan-OTBDPS/gelatin hydrogels.
• Exposure of sensors to varying concentrations of fluoride ions in aqueous solutions.
• Measurement of microcantilever bending deflection as a response to fluoride ion exposure.
• Testing selectivity against other common anions (Cl-, Br-, NO3-, H2PO4-, HSO4-, AcO-).

Main Results:

• Both developed microcantilever sensors demonstrated sensitive and selective detection of fluoride ions.
• Maximum bending deflection was found to be proportional to fluoride ion concentration.
• Achieved limits of detection were 10⁻⁸ M and 10⁻⁹ M for the two sensor types, respectively.
• The sensors exhibited minimal response to other tested ions, indicating high selectivity.

Conclusions:

• The developed microcantilever sensors are effective tools for the sensitive and selective detection of fluoride ions in aqueous solutions.
• The sensors enable in situ quantitative detection of fluoride ions.
• The bending mechanism, attributed to Si-O bond cleavage upon reaction with fluoride, is well-understood.