Electrochemical impedance spectroscopy sensor for ascorbic acid based on copper(I) catalyzed click chemistry

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Copper(I) species catalyze crucial reactions like azide-alkyne cycloaddition.
• Developing sensitive methods for detecting ascorbic acid (AA) is vital in various fields.
• Electrode modification enhances sensor performance for specific analyte detection.

Purpose of the Study:

• To develop a novel electrochemical sensor for sensitive ascorbic acid detection.
• To functionalize a gold electrode using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC).
• To characterize the sensor's performance, including stability, selectivity, and detection limits.

Main Methods:

• Electrode modification with propargyl-functionalized ferrocene via CuAAC reaction.
• Electrochemical impedance spectroscopy (EIS) to assess electron transfer resistance.
• Quantification of fractional surface coverage (θ) in relation to ascorbic acid concentration.

Main Results:

• A linear relationship was observed between fractional surface coverage (θ) and the logarithm of AA concentration (5.0 pmol/L to 1.0 nmol/L).
• The sensor achieved a low detection limit of 2.6 pmol/L for ascorbic acid.
• The developed sensor exhibited good stability and selectivity.
• Successful application of the sensor for AA detection in real urine samples.

Conclusions:

• The modified electrode serves as a robust platform for electrochemical sensing.
• The sensor offers a highly sensitive and selective method for ascorbic acid quantification.
• This approach demonstrates potential for practical applications in biological sample analysis.