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Sci Total Environ

Title:		Hollow fibre supported liquid membrane extraction for BTEX metabolites analysis in human teeth as biomarkers
Author(s):		Gonzalez JL; Pell A; Lopez-Mesas M; Valiente M;
Address:		"Centre Grup de Tecniques de Separacio en Quimica (GTS), Quimica Analitica, Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain. Centre Grup de Tecniques de Separacio en Quimica (GTS), Quimica Analitica, Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain. Electronic address: Manuel.Valiente@uab.cat"
Journal Title:		Sci Total Environ
Year:		2018
Volume:		20180223
Issue:
Page Number:		323 - 330
DOI:		10.1016/j.scitotenv.2018.02.195
ISSN/ISBN:		1879-1026 (Electronic) 0048-9697 (Linking)
Abstract:		"The use of human teeth as biomarkers has been previously applied to characterize environmental exposure mainly to metal contamination. Difficulties arise when the contaminants are volatile or its concentration level is very low. This study presents the development of a methodology based on the transport through hollow fibre membrane liquid-phase microextraction (HF-LPME), followed by HPLC-UV measurement, to determine three different metabolites of BTEX contaminants, mandelic acid (MA), hyppuric acid (HA), and methylhippuric acid (4mHA). The driving force for the liquid membrane has been studied by using both non-facilitated (pH gradient 2-12) and facilitated transport (ionic and non-ionic carriers). Enrichment factors of several hundreds were accomplished. Different ionic and non-ionic water insoluble compounds were used as metabolite carriers for the facilitated transport at HF-LPME. Three organic solvents were used to constitute the liquid membrane, dodecane, dihexyl ether and n-decanol. Other parameters affecting the extraction process, such as extraction time, stirring speed, acceptor buffer and salt content were optimised in spiked solutions and selected those that presented the best enrichment factors for all analytes. Final conditions were established for donor solution as 20mL, pH2 of 0.5M NaCl, the OLM (Organic Liquid Membrane) as n-decanol and the acceptor solution as 40muL of 1M NaOH. The selected extraction time was 20h with stirring speed of 500rpm. Validation of the optimised method included the determination of individual linearity range (MA: 0.002-5.7mug; HA: 0.01-7.9mug; 4mHA 0.002-5.3mug), limits of detection (MA: 1.6ng; HA: 0.2ng; 4mHA 0.2ng), repeatability (RSD 7-10%) and reproducibility (5-8%). The developed method was applied to the analysis of MA, HA and 4mHA in teeth samples of 8 workers exposed to BTEX"
Keywords:		Benzene/analysis Benzene Derivatives/*analysis Biomarkers/chemistry Environmental Exposure/*analysis Environmental Pollutants/*analysis Liquid Phase Microextraction/methods Toluene/analysis Tooth/*chemistry Xylenes/analysis 4-Methylhippuric acid Hippuric;
Notes:		"MedlineGonzalez, Johannes Luis Pell, Albert Lopez-Mesas, Montserrat Valiente, Manuel eng Netherlands 2018/02/27 Sci Total Environ. 2018 Jul 15; 630:323-330. doi: 10.1016/j.scitotenv.2018.02.195. Epub 2018 Feb 23"