Multivariate Optimization of an SPME Technique for GC-MS Analysis of Urinary BTX

Volatile organic compounds (VOCs), such as benzene, toluene and xylenes (BTX), are recognized as environmental contaminants due to their acute and chronic toxic effects, and toluene is a substance contained in products used in inhalants. In this way, methods able to determine these substances in non-invasive matrices offer great applicability for assessing acute exposure. In this study, a functionalized polymer, chloropropyltrimethoxysilane/polydimethylsiloxane, was evaluated as a potential material to be used in solid-phase microextraction for the quantification of BTX in urine by gas chromatography coupled to mass spectrometry (GC-MS). The method optimization was performed by using fractional factorial planning 2 (4-1) and the Doehlert's experiment. Desorption time and salinity were the most important factors that impact the sensitivity of the method. Spectroscopic and thermogravimetric characterization demonstrated the functionalization of the material and its thermal stability up to 390°C. This allowed it to be used for ~60 analytical cycles without loss of efficiency. The proposed method demonstrated a satisfactory analytical performance to determine the VOCs studied. The protocol agrees with the principles of green analytical chemistry since the procedure reduced the reagents consumed and wastes generated. It represents a promising tool for acute exposure assessment to BTX since urine tests demonstrated its applicability.