“Green” and Ultrafast Method for Determination of Soft Drink Ingredients on a Thermo Scientific™ Acclaim™ C18 RSLC Column

Significance of the Topic

Soft drinks are among the most popular beverages worldwide. Regular monitoring of sweeteners, preservatives and contaminants in these products is essential to ensure consumer safety, meet regulatory requirements and maintain product consistency. A rapid, reliable and eco-friendly analytical approach can greatly improve laboratory throughput and reduce environmental impact.

Objectives and Study Overview

This work presents a “green” and ultrafast liquid chromatography method for simultaneous determination of seven common ingredients in soft drinks: acesulfame-K, saccharin, aspartame, benzoic acid, sorbate potassium, caffeine and a trace contaminant, aspartylphenylalanine. Key goals include reducing analysis time, replacing toxic solvents, minimizing backpressure and enabling high sample throughput for routine quality control.

Methodology and Instrumentation

Sample Preparation:

• Degas samples by sonication to remove dissolved CO₂.
• Dilute to 150 µg/mL in water for standards and matrix samples.

Chromatographic Conditions:

• Column: Thermo Scientific Acclaim RSLC C18, 3.0 × 50 mm, 2.2 µm particle size.
• Mobile Phase A: 10 mM ammonium acetate, pH 5.
• Mobile Phase B: 50 % ethanol with 10 mM ammonium acetate.
• Gradient profile: initial 93 % A / 7 % B, ramp to 70 % A / 30 % B between 0.2 and 0.9 min, re-equilibration to initial conditions by 1.4 min.
• Flow rate: 1.5 mL/min; column temperature: 50 °C to lower viscosity and pressure.
• Injection volume: 2.0 µL, bypass loop at 0.20 min.
• Detection: UV at 230 nm, switching to 214 nm at 0.40 min with baseline subtraction using a water blank.

Main Results and Discussion

The optimized method achieves baseline resolution of all analytes in 1.4 min, corresponding to ~20 samples per hour. Hot operation reduces solvent viscosity, allowing high flow rates and maintaining pressure within system limits. Ethanol replaces acetonitrile, offering a less toxic, more sustainable alternative. Wavelength switching effectively minimizes interference from matrix components, particularly near acesulfame-K.

Benefits and Practical Applications

• High throughput: 2.6 min per sample speeds up routine QC workflows.
• Green chemistry: ethanol use and reduced solvent consumption lower environmental footprint.
• Robust performance: heated column operation and gradient design yield reproducible results.
• Wide applicability: suitable for various soft drink formulations and flavors.

Future Trends and Opportunities

Continued development may focus on coupling with mass spectrometry for enhanced sensitivity and selectivity, further miniaturization for field testing, and integration with automation platforms for fully seamless QC processes. Advances in host-guest chemistry and novel stationary phases may enable even faster separations and broader analyte coverage.

Conclusion

The described RSLC-C18 method offers a fast, accurate and environmentally friendly solution for soft drink ingredient analysis. Its combination of elevated temperature, ethanol-based mobile phase and rapid gradient delivers high throughput and robust performance, meeting quality control demands in beverage laboratories.

Reference

Thermo Fisher Scientific Inc. “Green and Ultrafast Method for Determination of Soft Drink Ingredients on a Thermo Scientific™ Acclaim™ C18 RSLC Column,” Application Note, 2009.