Rapid and sensitive UHPLC screening of additives in carbonated beverages with a robust organic acid column

Importance of the Topic

The monitoring of food additives in carbonated beverages is critical for quality control, regulatory compliance and consumer safety. Additives such as sweeteners, preservatives and acids shape flavor, extend shelf life and protect against microbial growth. Rapid, sensitive and reproducible analytical methods enable manufacturers and regulators to verify ingredient levels, detect counterfeiting and ensure product consistency.

Study Objectives and Overview

This work evaluates the performance of the Thermo Scientific Acclaim Organic Acid column paired with the Vanquish Flex Binary UHPLC system for the analysis of seven typical soft-drink additives. The goals were:

• To achieve rapid separation and quantification of citrate, acesulfame, saccharin, caffeine, aspartame, sorbate and benzoate by UHPLC-UV.
• To demonstrate linear calibration, method reproducibility and high analyte recoveries in carbonated beverage matrices.
• To verify retention time precision using the binary pump mixing technology.

Methodology

Standards were prepared by dissolving each additive in water to create primary stock solutions, which were combined into a mixed standard. Calibration curves covered low µg/mL to several hundred µg/mL ranges tailored to each analyte. Carbonated drinks were degassed in an ultrasonic bath, diluted (1:10 or 1:20), filtered through a 0.45 µm nylon membrane and spiked for recovery studies.

UHPLC conditions:

• Column: 150 mm × 2.1 mm, 3 µm Acclaim Organic Acid
• Mobile phase A: 100 mM KH2PO4, pH 3 (adjusted with methanesulfonic acid)
• Mobile phase B: Acetonitrile
• Gradient: 5 % B to 25 % B over 5 min, hold to 7 min, return to 5 % B at 7.1 min; total cycle ~10 min
• Flow rate: 0.6 mL/min; Column temperature: 50 °C; Detection: UV at 210 nm; Injection volume: 5 µL

Used Instrumentation

The analytical setup comprised:

• Thermo Scientific Vanquish Flex Binary UHPLC system (Binary Pump F, Split Sampler FT, Column Compartment H, Active Pre-heater)
• DAD HL detector with 2 µL LightPipe flow cell
• Thermo Scientific Virtuoso Vial Identification System
• Chromeleon 7.2 SR4 MUb software for data control and processing

Main Results and Discussion

Baseline separation of all seven additives was achieved in under 6 minutes with resolution factors >1.5. Retention time repeatability (n=9) showed RSDs between 0.01 % and 0.08 %, and peak area RSDs below 0.52 %. Calibration curves exhibited excellent linearity (R2 from 0.9957 to 0.9999). Spike recovery tests in three commercial drinks produced recoveries ≥93 %, with most above 98 %, indicating minimal matrix effects. Analysis of real samples identified citrate, caffeine and sorbate at µg/mL levels, with brand-specific profiles.

Benefits and Practical Applications

This UHPLC-UV approach offers:

• High throughput screening in quality control laboratories
• Robust performance in acidic, high-salt mobile phases
• Accurate quantitation of multiple additives in a single run
• Fast turnaround with reliable retention time and peak area precision

Future Trends and Opportunities

Potential developments include:

• Coupling to mass spectrometry for enhanced specificity
• Extension to a broader range of beverage matrices and emerging additives
• Further miniaturization and faster gradients for ultra-high throughput
• Integration with automated sample preparation and data analytics

Conclusion

The combination of the Acclaim Organic Acid column and Vanquish Flex Binary UHPLC system enables rapid, sensitive and reproducible screening of key additives in carbonated drinks. The method delivers robust linearity, precise retention times and high recovery rates, supporting routine quality control and authenticity testing in the beverage industry.

References

1. Aaron Lamb, Brian King. Application Note 21673. Thermo Fisher Scientific, 2017.