Simultaneous Determination of Uric Acid and Caffeine by Flow Injection Using Multiple-Pulse Amperometry

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Environmental Science

Background:

• Simultaneous determination of uric acid (UA) and caffeine (CAF) is crucial for various applications.
• Existing methods may lack sensitivity or selectivity for simultaneous analysis.
• Boron-doped diamond (BDD) electrodes show promise for sensitive electrochemical detection.

Purpose of the Study:

• To develop and validate a flow injection analysis (FIA) system for the simultaneous determination of UA and CAF.
• To utilize a cathodically pretreated boron-doped diamond (CPT-BDD) electrode with multiple-pulse amperometry (MPA).
• To assess the method's performance, including sensitivity, selectivity, and applicability to environmental samples.

Main Methods:

• Cyclic voltammetry was used to analyze the electrochemical profiles of UA and CAF.
• Multiple-pulse amperometry (MPA) was applied at optimized potentials (0.80 V for UA, 1.4 V for CAF).
• A flow injection analysis (FIA) system was coupled with a cathodically pretreated boron-doped diamond (CPT-BDD) electrode.

Main Results:

• The FIA-MPA method achieved linear concentration ranges of 5.0 × 10^-8-2.2 × 10^-5 mol L^-1 for UA and 5.0 × 10^-8-1.9 × 10^-5 mol L^-1 for CAF.
• Limits of detection were as low as 1.1 × 10^-8 mol L^-1 for UA and 1.3 × 10^-8 mol L^-1 for CAF.
• The method demonstrated good repeatability, stability, and no interference from common species, with 98-104% recovery in environmental samples.

Conclusions:

• The developed FIA-MPA system with a CPT-BDD electrode is effective for simultaneous UA and CAF determination.
• The sensor exhibits excellent analytical performance, comparable or superior to existing methods.
• This approach is suitable for sensitive and reliable analysis of UA and CAF in environmental matrices.