A non-invasive method for in vivo skin volatile compounds sampling.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Dermatology

Background:

• Volatile organic compounds (VOCs) from human skin hold diagnostic potential for skin diseases.
• Detecting these low-concentration VOCs requires efficient sampling preparation before analysis.
• Current methods may lack reproducibility or be invasive.

Purpose of the Study:

• To develop a simple, non-invasive headspace sampling method for skin VOCs.
• To evaluate the reproducibility and optimal conditions for the developed sampling technique.
• To apply the method for identifying dietary biomarkers and analyzing regional skin VOC profiles.

Main Methods:

• A novel thin-film based headspace sampling device ('membrane sandwich') was designed for skin VOCs.
• The method was validated for reproducibility (intra-/inter-membrane RSD% < 9.8%/8.2%), membrane size, extraction mode, and storage conditions.
• Gas chromatography-mass spectrometry (GC-MS) was used for VOC analysis.
• In vivo sampling was compared between headspace and direct methods.

Main Results:

• The developed sampling method demonstrated high reproducibility.
• Headspace sampling significantly reduced background noise compared to direct sampling.
• Membranes stored on dry ice for up to 72 hours maintained volatile profiles.
• Biomarkers for garlic intake (dimethyl sulphone, allyl methyl sulfide, allyl mercaptan) and alcohol were identified.
• Analysis of different body regions revealed common VOCs, with the upper back showing the highest compound density.

Conclusions:

• The novel skin VOC sampling approach is reproducible and effective for GC-MS analysis.
• This non-invasive technique can identify dietary biomarkers and analyze regional skin VOC variations.
• The method shows promise for advancing non-invasive diagnostics and understanding skin physiology.