Simultaneous determination of BTEX and their metabolites using solid-phase microextraction followed by HPLC or GC/MS: An application in teeth as environmental biomarkers.

Applications of benzene, toluene, ethylbenzene, and o-, m-, and p-xylenes (BTEX) release them into the environment exposing living organism. These endocrine disruptors are toxic, highly volatile and easily absorbed by the lungs and can cause adverse consequences for the human health as neurological diseases and cancer. A method for the analysis of BTEX and its metabolites (phenols and aromatic acids) in teeth is presented. The method consists in a one-step simple extraction procedure from spiked tooth using NaOH solution followed by SPME-HPLC or HS-SPME-GC/MS determination. Optimization of both, spiking procedure and extraction step of these analytes from tooth, was carried out. Two fibers CAR/PDMS for BTEX and PA for BTEX metabolites were used for the SPME and variables were optimized for analytes at 30°C using spiked solutions. The optimized adsorption times were 30, 75 and 30min and desorption times were 10, 40 and 30min for BTEX, phenols and aromatic acids, respectively. Linearity for SPME-HPLC method was established using spiked solutions with both, BTEX and metabolites, at 2.5, 5.0, 10.0, 25.0μg/mL. The obtained results indicated a good linearity (r above 0.994) for all analytes. Triplicate analyses were performed with RSD lower than 15%. LODs were in the range 0.2-33.3ng/mL for SPME-HPLC and 0.06-0.09pg/mL for HS-SPME-GC/MS methods in spiking solutions. Once the method was optimized, bovine teeth were used as biological matrix model for the tuning of spiking and extraction steps. Optimal adsorption and desorption times were 4h for both procedures. Micrograms per tooth gram of BTEX and phenols were quantified in ten human teeth and aromatic acids were not identified. The developed method for BTEX and metabolites analyses using SPME-HPLC or HS-SPME-GC/MS shows good precision, linearity and sensitivity. The method was successfully applied in human teeth as environmental biomarker of BTEX and metabolites.