Headspace SPME-GC-MS metabolomics analysis of urinary volatile organic compounds (VOCs).

In this chapter, we describe the procedure for metabolic profiling of hundreds of urinary volatile organic compounds (VOCs) using headspace solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). SPME is a solvent-free technology that is reproducible, fast, cost effective, and versatile in extracting small molecular weight organic compounds (metabolites) from biofluids using a fiber that is coated with an extracting phase. After extraction, the SPME fiber can be directly injected to the GC-MS, where the extracted metabolites will desorb thermally from the fiber, elute along a GC column, and finally enter into the MS for detection. The analysis of urine samples is presented using this approach.