A simple benzothiazolium-based sensor for cyanide detection: Applications in environmental analysis and bioimaging

Area of Science:

• Chemical Sensing
• Fluorescent Probes
• Analytical Chemistry

Background:

• Cyanide (CN-) is a highly toxic pollutant.
• Sensitive and selective detection methods for CN- are crucial for environmental and biological safety.
• Existing sensors often lack the required sensitivity or selectivity for real-world applications.

Purpose of the Study:

• To design and synthesize a novel fluorescent sensor, SU-1, for the detection of cyanide ions.
• To evaluate the sensor's performance in terms of sensitivity, selectivity, and response mechanism.
• To demonstrate the practical applicability of the sensor in environmental samples and biological imaging.

Main Methods:

• Synthesis of Ethylbenzothiazolium-2-hydroxynaphthaldehyde conjugate (SU-1).
• Structural characterization using NMR, HRMS, and single crystal XRD.
• Spectroscopic analysis (colorimetric and fluorometric) for CN- detection in DMSO:H2O.
• Determination of limit of detection (LOD), binding stoichiometry, and stability constant.
• Application testing in environmental water samples and live cell imaging.

Main Results:

• SU-1 was successfully synthesized and characterized.
• The sensor exhibited a visible color change and a 120 nm red-shift in absorption upon CN- addition.
• High selectivity for CN- was observed, with negligible interference from other anions.
• The limit of detection for CN- was 0.27 nM, well below the WHO guideline for drinking water.
• The sensor was successfully applied for detecting CN- in environmental water and imaging intracellular CN- in CAD cells.

Conclusions:

• The developed SU-1 sensor offers a highly sensitive and selective method for cyanide detection.
• Its distinct optical response and low detection limit make it suitable for environmental monitoring.
• The sensor's ability to perform intracellular imaging opens avenues for biological studies involving cyanide.