Selective "Turn-On" Fluorescent Sensor for Cyanide in Aqueous Environment and Test Strips

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Environmental Monitoring

Background:

• Cyanide ions pose significant environmental and health risks.
• Sensitive and selective detection methods for cyanide are crucial for monitoring.
• Existing methods may lack the required sensitivity or selectivity for real-world applications.

Purpose of the Study:

• To develop a new, highly sensitive, and selective fluorescent probe for cyanide ion detection.
• To investigate the sensing mechanism based on nucleophilic addition.
• To create practical test strips for cyanide recognition in aqueous environments.

Main Methods:

• Synthesis of a novel phenothiazine-based fluorescent probe.
• Spectroscopic analysis (UV-Vis absorption and fluorescence emission) to study probe-cyanide interaction.
• Preparation and testing of cyanide-detecting test strips.
• Evaluation of probe selectivity against common interfering anions.

Main Results:

• The phenothiazine probe exhibited a distinct color change from purple to yellow upon cyanide ion recognition.
• Fluorescence emission intensified with a shift to green under UV light.
• The probe demonstrated high selectivity for cyanide ions, with minimal interference from other anions.
• A low recognition limit of 7.2 × 10⁻⁸ mol/L for cyanide was achieved in dichloromethane.

Conclusions:

• A sensitive and selective fluorescent phenothiazine probe for cyanide detection has been successfully developed.
• The probe's colorimetric and fluorometric response provides a reliable method for cyanide sensing.
• The developed test strips offer a practical tool for on-site cyanide detection in aqueous media.