title: A novel hollow-fibre microporous membrane liquid-liquid extraction for determination of free 4-isobutylacetophenone concentration at ultra trace level in environmental aqueous samples.
abstract: In this study, a method was developed for determination of the free concentration of 4-isobutylacetophenone, a toxic degradation product of ibuprofen, in river and sewage water samples from Sweden. Sample preparation and analysis were performed by a hollow-fibre microporous membrane liquid-liquid extraction (HF-MMLLE) set-up and gas chromatography-mass spectrometry (GC-MS), respectively. In this novel approach, only the liquid in the membrane pores is utilised for non-depleting extraction. Several parameters were studied, including: type of organic solvent, sample pH, and salt and humic acid content. The optimised method allowed the determination of the analyte at the ng L(-1) level in river and sewage water. A linear plot gave a correlation coefficient better than 0.992 and resulted in a limit of detection of 7 and 14 ng L(-1) for river and sewage water, respectively. The enrichment factor was over 2000 in the fibre and over 300 after dilution. The repeatability and reproducibility were better than 5% and 10%, respectively. For the first time, 4-isobutylacetophenone was found at free concentrations of 40 ng L(-1) or below in sewage waters, while it could not be quantified in a river downstream from a municipal sewage treatment plant.
authors.affiliation: Division of Analytical Chemistry, University of Lund, SE-22100 Lund, Sweden. saioa.zorita@analykem.lu.se
authors.forename: Saioa
authors.initials: S
authors.lastname: Zorita
authors.forename: Thaer
authors.initials: T
authors.lastname: Barri
authors.forename: Lennart
authors.initials: L
authors.lastname: Mathiasson
mesh_terms: D000098:Acetophenones / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D012015:Reference Standards; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000098:Acetophenones; D006812:Humic Substances; D014874:Water Pollutants, Chemical; C524006:4-isobutylacetophenone