A simple method to quantify azo dyes in spices based on flow injection chromatography combined with chemometric tools

Area of Science:

• Analytical Chemistry
• Food Safety
• Chemometrics

Background:

• Para Red (PR) and Sudan dyes (Sudan I - SI, Sudan II - SII) are illegally used as food colorants.
• These dyes pose significant health risks, being toxic and carcinogenic.
• Accurate detection methods are crucial for ensuring food safety and preventing adulteration.

Purpose of the Study:

• To develop a simple, rapid, and reliable flow injection chromatographic method for determining PR, SI, and SII in food samples.
• To utilize chemometric tools for resolving overlapped spectral data.
• To validate the method's accuracy and compare it with a reference technique.

Main Methods:

• Development of a flow injection system using a low-pressure manifold and a reverse-phase monolithic column.
• Application of Partial Least Square (PLS) chemometric modeling to analyze absorption spectra.
• Validation using relative errors of calibration (RMSECV) and prediction (RMSEP), and residual predictive deviation (RPD).

Main Results:

• Low relative errors of calibration (0.23-0.85%) and prediction (0.33-1.12%) were achieved for PR, SI, and SII.
• Residual predictive deviation (RPD) values exceeded 3.00 for all analytes, indicating high model reliability.
• The method successfully quantified dyes in commercial spice samples, with results comparable to the HPLC reference method (p > 0.05).

Conclusions:

• The developed flow injection chromatographic method offers a simple, reliable, low-cost, and environmentally friendly approach for detecting illegal Sudan dyes in food.
• The integration of chemometric tools enhances spectral resolution and analytical accuracy.
• This method provides a viable alternative for routine food safety analysis and quality control.