Analysis of Organic Acids using a Mixed-Mode LC Column and an ACQUITY QDa Mass Detector

Importance of the Topic

Organic acids play a critical role in flavor aroma stability and microbial control in food beverages and other matrices Their characteristic profiles serve as authenticity markers in fruit juices and have broad relevance in quality control and research

Objectives and Study Overview

This study aimed to develop and validate a rapid selective method for the separation and quantitation of fifteen organic acids using a mixed mode Atlantis PREMIER BEH C18 AX column coupled to an ACQUITY UPLC H Class system with QDa mass detection The method was applied to analyze acid profiles in various fruit juices

Instrumentation Used

• ACQUITY UPLC H Class system
• Atlantis PREMIER BEH C18 AX column 1.7 mu m 2.1 x 100 mm
• ACQUITY QDa mass detector ESI negative mode
• Empower 3 chromatography data software

Main Results and Discussion

Optimization of mobile phase demonstrated that organic solvent content ionic strength and pH significantly affect retention factors and elution order of organic acids Buffer concentration influenced selectivity especially for low pKa acids while pH 2.9 provided optimal peak shape A binary gradient with a low ionic strength isocratic segment achieved complete separation of fifteen acids within eight minutes Detection in eleven Single Ion Recording channels minimized interference The method LOQ ranged from 0.2 to 6 mu g per mL Calibration showed linear response and spiking experiments in apple grape and pomegranate juices yielded recoveries predominantly within 80 to 120 percent

Method Benefits and Practical Applications

• Enhanced retention and chromatographic resolution of organic acids
• High sensitivity and selectivity reducing matrix interference
• Rapid analysis with runtime under eight minutes
• Applicability to authenticity testing and quality control of fruit juices and beverages

Future Trends and Potential Applications

Increased use of internal standards for improved quantitation integration with high resolution mass spectrometry for structural confirmation expansion to complex food environmental and biological samples and adoption of greener solvents and automated workflows may further enhance application scope

Conclusion

The combined Atlantis PREMIER BEH C18 AX column and ACQUITY UPLC QDa system delivers a robust rapid and selective solution for organic acid analysis offering superior chromatographic performance and sensitive detection suitable for diverse quality control and research applications

References

1. Monica Gonzalez Venerando Gonzalez Organic Acids in Food Analysis by HPLC Third Edition CRC Press Taylor Francis Group 2013 443
2. Hyoung S Lee HPLC Method for Separation and Determination of Non Volatile Organic Acids in Orange Juice Journal of Agricultural and Food Chemistry 1993 41 1991 1993
3. Thomas H Walter Bonnie A Alden Cheryl Boissel Jessica Field Nicole Lawrence Donna Osterman Amit Patel A New Mixed Mode Reversed Phase Anion Exchange Stationary Phase Based on Hybrid Particles Waters Application Note 2020
4. AOAC Guidelines for Single Laboratory Validation of Chemical Methods for Dietary Supplements and Botanicals Official Methods of Analysis 19th Edition Appendix K AOAC INTERNATIONAL 2012
5. Stefan Ehling Shannon Cole Analysis of Organic Acids in Fruit Juices by LC MS An Enhanced Tool for Authenticity Testing Journal of Agricultural and Food Chemistry 2011 59 2229 2234