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Biosensor-based determination of riboflavin in milk samples
Isabelle Caelen1, Andras Kalman, Lennart Wahlström
1Nestlé Research Center Lausanne, Nestec Ltd, Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland. isabelle.caelen@rdls.nestle.com
Analytical Chemistry
|December 31, 2003
Summary
A new surface plasmon resonance assay quantifies riboflavin (Rf) in milk products. This method measures free riboflavin binding protein (RBP) after binding, offering accurate results comparable to HPLC.
Area of Science:
- Analytical Chemistry
- Biochemistry
- Biosensing Technology
Background:
- Riboflavin (Rf), also known as Vitamin B2, is essential for human health.
- Accurate quantification of riboflavin in food matrices like milk products is crucial for quality control and nutritional labeling.
- Existing methods, such as HPLC-fluorescence, can be time-consuming and require complex sample preparation.
Purpose of the Study:
- To develop and validate a novel, rapid assay for the quantification of riboflavin (Rf) in milk-based products.
- To utilize surface plasmon resonance (SPR) for sensitive and specific on-chip detection of riboflavin.
- To establish an indirect quantification method based on measuring unbound riboflavin binding protein (RBP).
Main Methods:
- Development of an SPR assay utilizing a chip surface modified with covalently immobilized riboflavin.
- Chemical modification of riboflavin to introduce a reactive ester group for stable immobilization.
- Indirect quantification by measuring the excess riboflavin binding protein (RBP) remaining free after complexation with riboflavin in the sample.
- Preparation of calibration curves using standard riboflavin solutions and optimized RBP concentrations.
- Validation against a standard High-Performance Liquid Chromatography (HPLC)-fluorescence method.
Main Results:
- The developed SPR assay successfully quantified riboflavin in milk-based products.
- Results obtained from the SPR assay showed high correlation and close agreement with the official HPLC-fluorescence procedure.
- The assay demonstrated a limit of quantification of 234 µg/L and a limit of detection of 70 µg/L with a 160 µL injection volume.
- The method relies on measuring the free RBP after binding with sample riboflavin, indicating high specificity.
Conclusions:
- The developed on-chip surface plasmon resonance assay provides a sensitive, rapid, and accurate method for riboflavin quantification in milk-based products.
- This SPR-based approach offers a viable alternative to conventional methods like HPLC, potentially reducing analysis time and complexity.
- The assay's performance, including its limits of detection and quantification, supports its application in routine quality control of dairy products.