Development of an LC-Based Metabolomic Approach for Polar Compounds in Brewage Samples using Fast Polarity Switching TOFMS Acquisition

Significance of the topic

Polar metabolites such as amino acids nucleic acids and organic acids influence beer quality flavor and fermentation efficiency
LC based metabolomic profiling provides high sensitivity and selectivity for comprehensive analysis of these compounds

Objectives and overview

Develop a high throughput LC MS method using fast polarity switching time of flight mass spectrometry TOFMS for profiling polar metabolites in diverse beer samples
Identify specific endogenous markers related to malt content and monitor quality changes under degradation conditions

Methodology and instrumentation

• UHPLC system Shimadzu Nexera coupled to LCMS IT TOF
• Column Phenomenex Synergi Hydro RP 80A 150 mm x 2 mm id 4 um
• Mobile phase Water with 0.1 percent formic acid and 80 percent acetonitrile with 0.1 percent formic acid gradient from 0 to 100 percent over 22 minutes
• Flow rate 0.2 ml per minute column temperature 40 degrees C injection volume 2 microliters
• ESI in positive and negative mode with fast polarity switching probe voltages of 4.5 kV and 3.5 kV gas flows and temperatures optimized for ionization
• Mass range m z 85 to 1000 external calibration mass accuracy below 3 ppm
• Data processing using formula prediction isotope modeling and MSn verification SIMCA P plus for multivariate statistics and PCA

Main results and discussion

Approximately 60 positive and 30 negative peaks detected within a 20 minute separation
Accurate mass and MSn data enabled identification of key metabolites including tyrosine phenylalanine proline pyroglutamic acid fumaric acid hypoxanthine tryptophan and citric acid
PCA on 25 beer samples yielded six clusters correlating with malt category including third beer low malt standard and high malt samples explaining over 50 percent of variance
Characteristic ions m z 205.097 and m z 191.019 served as markers for high malt content
Degradation study on a high malt beer heated at 60 degrees C revealed distinct profiles after extended treatment with m z 252.109 identified as deoxyadenosine decreasing over time

Benefits and practical applications

• Rapid comprehensive profiling of polar metabolites for quality assurance in brewing
• Chemical fingerprinting enables classification of beer types by malt content
• Monitoring of product stability and identification of degradation pathways
• Method extensible to other beverages biofluids and industrial quality control

Future trends and potential applications

Enhanced sensitivity through improved ion sources and high resolution mass analyzers
Integration with automated workflows expanded spectral libraries and real time process monitoring
Application in food clinical environmental and industrial metabolomic studies for broader impact

Conclusion

The fast polarity switching LC TOFMS approach offers a robust high throughput platform for polar metabolite profiling in beer samples
Combined with multivariate analysis it enables precise marker discovery classification and degradation assessment supporting quality control and process optimization

References

1 I Duarte et al Journal of Agricultural and Food Chemistry 2002 50 2475 2481
2 C Almeida et al Journal of Agricultural and Food Chemistry 2006 54 700 706
3 S Yamaki et al 59th ASMS Conference Denver WP 354 2011