title: Improving analysis of apolar organic compounds by the use of a capillary titania-based column: Application to the direct determination of faecal sterols cholesterol and coprostanol in wastewater samples.
abstract: This article reports a new procedure for the direct determination of faecal sterols coprostanol and cholesterol in wastewater samples as tracers of human sewage contamination. The method combines in-tube solid-phase microextraction (IT-SPME) for analyte enrichment and capillary liquid chromatography (LC) for separation with diode array detection for identification and quantification. A titania-based polymeric capillary column and a conventional octadecyl silica (ODS) capillary column were evaluated and compared for their ability to separate the analytes. The titania-based column allowed the separation of the analytes in much shorter chromatographic times and with better chromatographic profiles, which in turn resulted in better detectability. In addition, IT-SPME allowed the direct injection into the chromatographic system of sample volumes as large as 200 μL, thus making unnecessary off-line clean-up and concentration steps. In such a way, the tested compounds could be directly analysed in less than 10 min, the limits of detection (LODs) being 10 and 1.2 μg/L for coprostanol and cholesterol, respectively. The reliability of the proposed method was tested by processing several wastewater samples.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, Spain.
authors.forename: Y
authors.initials: Y
authors.lastname: Moliner-Martinez
authors.forename: R
authors.initials: R
authors.lastname: Herráez-Hernández
authors.forename: C
authors.initials: C
authors.lastname: Molins-Legua
authors.forename: P
authors.initials: P
authors.lastname: Campins-Falcó
mesh_terms: D004083:Cholestanol / Q000032:analysis*; D002784:Cholesterol / Q000032:analysis*; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D005243:Feces / Q000737:chemistry; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012722:Sewage / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000295:instrumentation / Q000379:methods*
chemical_list: D012722:Sewage; D004083:Cholestanol; D002784:Cholesterol