Flow-through sensor for the fluorimetric determination of cyanide

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Cyanide detection is crucial for environmental monitoring and industrial safety.
• Existing fluorimetric and photometric methods for cyanide determination often lack sufficient selectivity.
• Flow-injection analysis (FIA) offers rapid and automated sample processing.

Purpose of the Study:

• To develop a novel, highly selective fluorimetric method for cyanide determination.
• To utilize pyridoxal-5-phosphate and an anion-exchange resin within a flow-injection system.
• To evaluate the method's performance characteristics, including linearity, precision, and sampling rate.

Main Methods:

• A merging-zone flow-injection manifold was employed for simultaneous sample and reagent injection.
• Cyanide reacted with pyridoxal-5-phosphate, with the product retained on an anion-exchange resin (QAE Sephadex) in the detector flow-cell.
• Fluorimetry was used for sensitive detection of the reaction product.

Main Results:

• The calibration graph for cyanide was linear over the concentration range of 50 ng/ml to 3.0 µg/ml.
• The method demonstrated a low relative standard deviation of 1.4% at 2 µg/ml cyanide.
• A sampling frequency of 10 samples per hour was achieved.
• Significantly improved selectivity compared to conventional fluorimetric and photometric FIA methods for cyanide was observed.

Conclusions:

• The proposed fluorimetric method offers a sensitive, precise, and selective approach for cyanide determination.
• The integration of pyridoxal-5-phosphate, QAE Sephadex, and merging-zone FIA provides enhanced analytical performance.
• This method represents a valuable advancement for cyanide analysis in various applications.