Quantifying exhaled acetone and isoprene through solid phase microextraction and gas chromatography-mass spectrometry

Area of Science:

• Analytical Chemistry
• Biomarkers
• Respiratory Medicine

Background:

• Volatile organic compounds (VOCs) in exhaled breath, such as acetone and isoprene, serve as crucial biomarkers for various medical conditions.
• Current methods for VOC detection, including solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS), often lack standardized quantification protocols.
• Quantifying exhaled volatiles is challenging due to the extensive need for calibration standards, making it a time-consuming process.

Purpose of the Study:

• To develop an accessible and standardized method for quantifying acetone and isoprene in human breath.
• To establish a reliable system for measuring volatile organic compounds (VOCs) in exhaled breath samples.

Main Methods:

• A system was engineered to simulate human exhalation, exposing volatile organic compounds (VOCs) to a solid phase microextraction (SPME) fiber at controlled concentrations.
• Gas chromatography-mass spectrometry (GC-MS) was employed for the identification and quantification of acetone and isoprene.
• Calibration curves were generated for acetone and isoprene, demonstrating a high linear correlation.

Main Results:

• The developed system accurately quantified acetone and isoprene in breath samples, with limits of detection at 12 ppb/37 ppb and 73 ppb/222 ppb, respectively.
• Quantification of acetone in healthy individuals ranged from 71 ppb to 294 ppb, while isoprene levels varied between 170 ppb and 990 ppb.
• The measured concentration ranges for both acetone and isoprene align with previously reported values in scientific literature.

Conclusions:

• A robust system for quantifying acetone and isoprene in exhaled breath has been successfully developed.
• This method is adaptable for various sampling techniques and analytical instruments beyond SPME-GC-MS.
• The findings pave the way for more standardized and accessible breath analysis in clinical and research settings.