Headspace Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry for the Determination of Volatile Organic Compounds in Urine

Determination of volatile organic compounds (VOCs), the metabolites produced in human body, contributes to better understanding of the mechanisms responsible for the progression of diseases and facilitates monitoring of the responses to treatment. Urine samples are a rich source of VOCs and they constitute a non-invasive tool for diagnosis of various metabolic and pathological states. The aim of this study was to optimize the headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC/MS) method for analysis of urine samples on the example of urine collected from children with celiac disease. Pooled urine samples from three children with celiac disease were used to select the optimal fibers, time and temperature of extraction, salt dose, and pH to achieve the highest SPME efficiency. Analysis performed with the use of divinylbenzene/carboxen/polydimethylsiloxane fiber in acidic pH with the addition of 1.5 g of sodium chloride supported the extraction of the highest number of VOCs with the largest total peak area. The extraction conducted at 60 degrees C for 45 min led to an optimal improvement in efficiency with a reduced number of siloxane derivatives, indicative of degradation of septa, fiber, and/or GC column stationary phase. The optimized HS-SPME-GC/MS method can be successfully applied to the determination of VOCs in urine samples.