Track-etched membrane-based dual-electrode coulometric detector for microbore/capillary high-performance liquid...

Area of Science:

• Analytical Chemistry
• Electrochemistry

Background:

• Microbore and capillary High-Performance Liquid Chromatography (HPLC) require sensitive detection methods with low flow rates.
• Electrochemical detection offers high sensitivity but can be limited by cell volume and efficiency.

Purpose of the Study:

• To develop and evaluate a dual-electrode coulometric detector with a track-etched microporous membrane for microbore/capillary HPLC.
• To assess the detector's performance for the sensitive determination of catecholamines.

Main Methods:

• A flow cell with a 0.1-mm inlet channel and microporous membrane electrodes was designed for dual-electrode coulometric detection.
• The detector's performance was evaluated using l-ascorbic acid and catecholamines (noradrenaline, adrenaline, dopamine) at low eluent flow rates (<50 μL/min).
• Detection limits and relative standard deviations (RSD) were determined for catecholamine analysis.

Main Results:

• The flow cell achieved a small detection volume (0.08 nL per electrode, 0.24 nL total).
• Electrooxidation efficiency for l-ascorbic acid approached 100% at flow rates below 50 μL/min.
• Catecholamines were detected with high sensitivity (0.1-0.2 μM detection limits) and precision (RSD < 1.5%).

Conclusions:

• The proposed electrochemical flow cell is suitable for sensitive and efficient coulometric detection in microbore/capillary HPLC.
• The dual-electrode system enables the accurate determination of catecholamines in pharmaceutical samples.