Rapid Identification of Double Bond Positions of Lipids in Butter by using Probe ESI Q-TOF LCMS-9050 and OAD-MS/MS

Importance of the Topic

Precise identification of double‐bond positions in lipids is critical for understanding nutritional value, oxidative stability and bioactivity of dairy fats. Rapid, simplified lipid structural analysis streamlines quality control in food science and advances lipidomics research.

Study Objectives and Overview

This work applies a combined probe electrospray ionization (PESI) and oxygen attachment dissociation (OAD) MS/MS approach on a Q‐TOF platform to rapidly determine double‐bond positions in triglycerides extracted from butter. Two target species, TG(38:1) and TG(38:2), were selected to validate the method.

Methodology

Butter samples undergo a simple five‐minute extraction using water/isopropanol (20:80, v/v) followed by centrifugation. The supernatant is directly analyzed by PESI on a Shimadzu DPiMS™ QT Q‐TOF, interfaced with an LCMS‐9050 system equipped with an OAD fragmentation module. MS‐DIAL software processes full‐scan data to generate candidate lipid lists; subsequent MS/MS spectra are acquired in CID and OAD modes for structural elucidation.

Instrumentation Used

• Shimadzu Probe Electrospray Ionization (PESI) Q‐TOF DPiMS™ QT
• Shimadzu LCMS‐9050 with integrated Oxygen Attachment Dissociation (OAD) unit

Main Results and Discussion

CID fragmentation yielded characteristic neutral‐loss ions corresponding to fatty acyl chain lengths (e.g., losses of 16:0, 18:1). OAD spectra provided specific cleavages at double‐bond sites, enabling precise localization of unsaturations in TG(38:1) and TG(38:2). The dual‐mode approach resolved isomeric species and assigned positional isomers in under five minutes per sample.

Benefits and Practical Applications

• Minimal sample preparation reduces analysis time and solvent usage.
• Direct probe ionization accelerates throughput for routine quality control.
• OAD fragmentation offers unambiguous double‐bond localization without derivatization.
• Applicable to food industry QC, nutritional profiling and lipidomics workflows.

Future Trends and Potential Applications

Scaling this methodology for high‐throughput platforms and coupling with advanced data processing or AI‐based spectral interpretation will enhance comprehensive lipidome mapping. Extending OAD‐based structural analysis to diverse lipid classes and complex biological matrices can support biomarker discovery and clinical lipidomics.

Conclusion

The integration of PESI and OAD on a Q‐TOF LCMS system provides a rapid, reliable and solvent‐efficient workflow for detailed structural characterization of triglyceride unsaturations in butter. This approach holds significant potential for broad applications in food science and lipid research.