Methods to Detect Volatile Organic Compounds for Breath Biopsy Using Solid-Phase Microextraction and Gas...

Area of Science:

• Analytical Chemistry
• Biomarker Discovery
• Respiratory Medicine

Background:

• Volatile organic compounds (VOCs) in exhaled breath are metabolic byproducts and potential disease biomarkers.
• Gas chromatography-mass spectrometry (GC-MS) is the gold standard for VOC analysis, requiring effective sampling techniques.
• Solid-phase microextraction (SPME) is a versatile sampling method for VOCs.

Purpose of the Study:

• To develop and compare novel and existing methods for sampling and preconcentrating VOCs from exhaled breath.
• To evaluate the performance of direct-breath SPME (DB-SPME), Tedlar-bag SPME (Tedlar-SPME), and cryotransfer methods.
• To identify the optimal breath sampling strategy for different VOCs and analytical needs.

Main Methods:

• Development and optimization of an in-house direct-breath SPME (DB-SPME) method.
• Quantitative comparison of DB-SPME against Tedlar-SPME and cryotransfer methods using GC-MS/QTOF.
• Analysis of breath samples (n=15 per method) for targeted VOCs including acetone, isoprene, toluene, limonene, and pinene.

Main Results:

• The cryotransfer method demonstrated the highest overall sensitivity for most VOCs.
• Tedlar-SPME provided superior sensitivity for low molecular weight VOCs like acetone and isoprene.
• DB-SPME was less sensitive but offered rapid analysis with minimal GC-MS background noise.

Conclusions:

• All three methods effectively detect a wide range of VOCs in exhaled breath.
• Cryotransfer is optimal for large sample sets and long-term storage at -80°C.
• Tedlar-SPME is effective for small VOCs, while DB-SPME is suitable for immediate analysis.