Construction of an optical sensor for the determination of ascorbic acid using ionic liquids as modifier

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Materials Science

Background:

• Ascorbic acid determination is crucial in food and health analysis.
• Existing methods for ascorbic acid measurement can be complex or time-consuming.
• Development of sensitive and rapid analytical tools is ongoing.

Purpose of the Study:

• To design and validate a novel optode for the indirect determination of ascorbic acid.
• To enhance the sensitivity and performance of the optode using room-temperature ionic liquids.
• To assess the applicability of the developed optode for real-world sample analysis.

Main Methods:

• An optode was fabricated by coating neocuproine onto a triacetylcellulose film.
• Ascorbic acid was indirectly quantified via its oxidation to dehydroascorbic acid using Cu(II) and neocuproine.
• Absorbance measurements at 455 nm were correlated with ascorbic acid concentration.
• Room-temperature ionic liquid, [C(8)MIM][PF(6)], was incorporated to improve sensitivity.

Main Results:

• The optode exhibited a linear dynamic range of 7.4 × 10(-5) - 3.5 × 10(-3) mol L(-1) for ascorbic acid.
• A low limit of detection of 2.2 × 10(-5) mol L(-1) was achieved.
• The response time for the determination ranged from 6.0 to 8.0 minutes.
• The method demonstrated successful application in determining ascorbic acid in orange juice samples.

Conclusions:

• The developed optode offers a sensitive and efficient method for ascorbic acid determination.
• The use of room-temperature ionic liquid significantly improved the optode's performance.
• This approach provides a viable tool for analyzing ascorbic acid in complex matrices like beverages.