Different Food Applications on a Single LC System Using Automated Column and Solvent Selection

Significance of the Topic

Liquid chromatography is a cornerstone technique for detecting food additives such as antioxidants, sweeteners, and preservatives. Automating column and solvent changes on a single LC system addresses the need for high throughput, method flexibility, and reduced downtime in food control and quality-assurance laboratories.

Objectives and Overview of the Study

This work demonstrates the Agilent 1260 Infinity II Multimethod solution’s capability to perform multiple LC applications—antioxidant, sweetener, and preservative analysis—on one instrument without manual reconfiguration by using automated column switching and solvent selection.

Methodology

Sample preparation was tailored to each matrix: chewing gum was ultrasonically extracted with acetonitrile; a sugar-free energy drink was degassed and filtered; and a facial tonic was diluted and filtered. Methods were defined as sequences comprising separate gradient programs, each specifying the desired column and mobile phases as parameters. Up to four columns and 15 solvent channels were orchestrated in a single analytical workflow.

Instrumentation

• Agilent 1260 Infinity II Quaternary Pump with solvent selection valve cluster
• Agilent 1260 Infinity II Multicolumn Thermostat with 4-position valve and column tag reader
• Agilent 1260 Infinity II Multisampler with cooling
• Agilent 1260 Infinity II Diode Array Detector HS
• Columns: Poroshell 120 SB-C18, EC-C18, and EC-C8 (4.6 × 100 mm, 2.7 µm)
• Solvents: water with acid modifiers, acetonitrile, isopropanol
• Software: Agilent OpenLAB CDS ChemStation

Main Results and Discussion

• Antioxidants: Baseline separation of BHA, BHT, PG, TBHQ, and THBP with retention time RSD <0.1% and area RSD <1%; minor degradation observed in some standards over repeated injections.
• Sweeteners: Acesulfame K, aspartame, and saccharin were resolved with high precision (RT and area RSD <0.2%) and identified in energy drink samples by retention time and UV spectra.
• Preservatives: Sorbic acid, benzoic acid, and salicylic acid showed consistent retention and quantitation (RT RSD <0.1%, area RSD <0.2%); salicylic acid was detected in a facial tonic matrix.

Benefits and Practical Applications

• Eliminates manual column and mobile phase exchanges, reducing instrument downtime.
• Supports over 100 separation conditions in a single sequence for versatile method deployment.
• Column tagging ensures traceability of usage history and protects column lifetime.
• Enhances laboratory throughput in routine QA/QC and regulatory food analysis.

Future Trends and Opportunities

• Integration with mass spectrometry detectors to expand analyte coverage and selectivity.
• Development of AI-driven method optimization for automated gradient and column selection.
• Online sample preparation and real-time data evaluation to further streamline workflows.
• Expansion into more complex food matrices and emerging contaminants.

Conclusion

The Agilent 1260 Infinity II Multimethod solution streamlines multi-application liquid chromatography by automating column and solvent changes, delivering reproducible results for diverse food and cosmetic samples, and significantly improving laboratory efficiency.

References

1. Naegele E., The Agilent 1290 Infinity II Multimethod Solution, Agilent Technologies Application Note 5991-5679EN, 2015.
2. Belitz H.-D. et al., Food Chemistry, 4th ed., Springer, 2009.
3. Judefeind F. et al., Stable isotope dilution analysis of salicylic acid and hydroquinone in human skin samples by GC-MS, Journal of Chromatography B 852 (2007): 300–307.
4. Gratzfeld-Huesgen A., Naegele E., The Agilent 1290 Infinity Multimethod Solution, Application Note 5990-5600EN, 2010.