Quantitative SERS analysis of azorubine (E 122) in sweet drinks

Area of Science:

• Analytical Chemistry
• Food Science
• Spectroscopy

Background:

• Quantitative detection of synthetic dyes in food and beverages is crucial for human health and accurate food composition knowledge.
• Synthetic dyes, like azorubine (E 122), are common food additives requiring reliable analytical methods for monitoring.
• Existing methods may require complex sample preparation, limiting rapid analysis.

Purpose of the Study:

• To develop and validate a fast, quantitative surface-enhanced Raman scattering (SERS) method for azorubine (E 122) detection in complex beverage matrices.
• To assess the method's sensitivity, accuracy, and applicability to real-world food samples without prior treatment.
• To establish SERS as a viable prescan technique for food safety and quality control.

Main Methods:

• Utilized highly uniform gold "film over nanospheres" (FON) substrates for SERS analysis.
• Employed the Raman signal from the silicon support as an internal intensity standard for quantification.
• Analyzed seven commercially available sweet drinks, including controls, directly using SERS without sample preparation.

Main Results:

• Achieved sensitive quantitative determination of azorubine (E 122) in beverages within a concentration range of 0.5–500 mg L(-1).
• Demonstrated a close correlation between SERS results and those obtained using the standard High-Performance Liquid Chromatography (HPLC) technique.
• The entire SERS analysis, including sample handling and spectral acquisition, was completed in just 35 minutes.

Conclusions:

• The developed SERS method provides a simple, rapid, and direct approach for quantitative azorubine (E 122) analysis in beverages.
• This technique eliminates the need for sample pretreatment, making it highly suitable for field applications and preliminary food testing.
• SERS offers a promising alternative to conventional methods for routine food safety monitoring and quality assurance.