A Novel Near-Infrared Fluorescent Probe for Quantifying Cysteine in Fruit and Vegetable Samples

Area of Science:

• Analytical Chemistry
• Food Science
• Biochemistry

Background:

• Cysteine (Cys) is an essential amino acid vital for human health and extensively used in the food industry.
• Accurate Cys quantification is crucial for food quality and safety.
• Existing fluorescent probes often face limitations in complex food matrices.

Purpose of the Study:

• Develop a novel dual-channel near-infrared (NIR) fluorescent probe, termed NC-NIR.
• Achieve selective and sensitive quantification of Cys in diverse food samples.
• Address limitations of current Cys detection methods in food applications.

Main Methods:

• Systematic evaluation of the NC-NIR probe's performance.
• Characterization of dual-channel response spectra and reaction mechanism.
• Assessment of limit of detection (LOD), selectivity, response time, and real-sample analysis feasibility.

Main Results:

• The NC-NIR probe demonstrated high selectivity and a low LOD of 34 nM for Cys.
• A distinct dual-channel fluorescence response was observed at 550 nm and 825 nm.
• Successful Cys detection was achieved in apples, jujubes, broccoli, pears, onions, and milk slices, leveraging NIR characteristics to minimize food background fluorescence.

Conclusions:

• The developed dual-channel NIR probe presents a promising strategy for in-situ Cys quantification in food.
• This probe offers a low-background, highly selective, and sensitive method for Cys detection.
• The NC-NIR probe facilitates accurate Cys analysis in various food products.