Electrophoretic analysis of food dyes using a miniaturized microfluidic system

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Separation Science

Background:

• Food dye analysis is crucial for consumer safety and regulatory compliance.
• Existing methods for food dye detection can be time-consuming and lack sensitivity.
• On-chip preconcentration and separation offer potential for faster, more sensitive analyses.

Purpose of the Study:

• To develop a simple, sensitive on-chip method for preconcentration, separation, and electrochemical detection of food dyes.
• To integrate field-amplified sample stacking (FASS) and field-amplified sample injection (FASI) with micellar electrokinetic chromatography and electrochemical detection (MEKC-ED).
• To demonstrate the method's applicability for analyzing food dyes in real food samples.

Main Methods:

• Developed a three-channel microchip for FASS, FASI, and MEKC-ED.
• Employed chronoamperometric detection with a glassy carbon electrode.
• Optimized experimental parameters to enhance analytical performance.
• Utilized a simplified, faster extraction method for food dyes from real samples.

Main Results:

• Achieved an approximate 10,800-fold increase in sensitivity compared to conventional MEKC-ED.
• Demonstrated reproducible results with relative standard deviation (RSD) <7.2% (n=5).
• Established linear calibration plots (r²=0.998) from 1.0 nM to 1.0 µM for food dyes.
• Obtained limit of detections (LODs) between 1.0 and 5.0 nM (S/N=3).

Conclusions:

• The developed on-chip method provides a simple, sensitive, and rapid approach for food dye analysis.
• The integration of FASS/FASI with MEKC-ED significantly enhances detection limits.
• The method is suitable for the practical analysis of food dyes in real-world samples.