Cross-validation of the peppermint benchmarking experiment across three analytical platforms

Area of Science:

• Analytical Chemistry
• Biomarker Discovery
• Pharmacokinetics

Background:

• Breath analysis lacks inter-comparability for biomarker studies.
• Volatile terpene washout profiles are key indicators.
• Standardized benchmarking is crucial for reliable results.

Purpose of the Study:

• To benchmark analytical platforms for breath analysis.
• To characterize terpene washout profiles from peppermint oil.
• To identify sources of variability in breath biomarker studies.

Main Methods:

• The Peppermint Experiment involved 11 volunteers providing triplicate breath samples.
• Analysis used Proton Transfer Reaction-Time-of-Flight-Mass Spectrometry (PTR-TOFMS), Gas Chromatography-Ion Mobility Spectrometry (GC-IMS), and Thermal Desorption Comprehensive Two-dimensional Gas Chromatography-Time-of-Flight-Mass Spectrometry (TD-GC×GC-TOFMS).
• Breath samples were collected using Buffered End-tidal (BET) samplers, handheld direct breath samplers, and Respiration Collection for in-vitro Analysis (ReCIVA) systems.

Main Results:

• Mean washout times were 448 min (PTR-TOFMS, GC-IMS) and 372 min (TD-GC×GC-TOFMS), aligning with benchmarks.
• Significant inter- and intra-individual variability in terpene washout profiles was observed.
• Low inter-instrument variability suggests biological factors drive outcome differences.

Conclusions:

• Biological variability, not analytical platform performance, is the primary driver of differing results in independent breath biomarker studies.
• Standardized breath analysis protocols are essential for consistent and comparable results.
• The Peppermint Experiment provides a benchmark for future breath analysis research.