Microfabricated electrochemical detector for high-performance liquid chromatography.

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Microfabrication

Background:

• Traditional electrochemical detectors require electrode polishing, increasing downtime and cost.
• Disposable detectors can streamline analytical workflows and reduce maintenance burdens.
• Microfabrication techniques enable the development of miniaturized and cost-effective analytical devices.

Purpose of the Study:

• To develop and evaluate a microfabricated electrochemical cell as a disposable detector for FIA and HPLC.
• To assess the performance, linearity, and detection limits of the disposable detector.
• To compare the detector's performance against commercial systems.

Main Methods:

• Fabrication of a disposable electrochemical cell using thin-film metal electrodes (Pt, Ag/AgCl) on a polyimide substrate.
• Integration of a microfluidic cover for controlled solution flow over the electrodes.
• Evaluation using flow injection analysis (FIA) of ferrocyanide and HPLC of ascorbic acid, acetaminophen, and a pharmaceutical mixture.

Main Results:

• The microfabricated detector demonstrated good linearity (R(2) > 0.99) for HPLC analysis.
• Achieved low limits of detection: 1 nM for acetaminophen and ascorbic acid, 50 nM for dextrorphan, and 80 nM for levallorphan.
• Comparable chromatographic results were obtained when compared to a commercial detector, despite slightly higher LODs for some analytes.

Conclusions:

• The microfabricated electrochemical cell serves as a viable, low-cost, disposable alternative for FIA and HPLC detection.
• The disposable nature simplifies operation and maintenance, making it suitable for routine analysis.
• Performance degradation was observed due to AgCl dissolution, indicating a limitation for extended continuous use without reference electrode replenishment.