title: New medium-to-high polarity twister coatings for liquid and vapour phase sorptive extraction of matrices of vegetable origin.
abstract: Stir Bar Sorptive Extraction (SBSE) is a solventless sampling technique first introduced to extract organic analytes from aqueous samples, in the following applied to headspace sampling (HeadSpace Sorptive Extraction - HSSE). In SBSE and HSSE, analytes are sorbed onto a thick film of polydimethylsiloxane (PDMS) coating a glass-coated magnet. However, PDMS is apolar and not highly effective in recovering polar analytes (i.e. with logK(o/w) below 2), making difficult their sampling in complex matrices. A new generation of medium-to-high polarity polymeric coatings for twisters i.e. polyethyleneglycol-modified silicone (EG) and polyacrylate/polyethyleneglycol (PA) has recently been introduced to overcome this limit. In this study, EG and PA twisters have been applied to SBSE and HSSE of a number of dedicated standard mixtures and real-world samples of vegetable origin to evaluate their capability to increase recovery of medium to highly polar analytes. The results obtained, expressed as percent concentration factor (CF%) versus PDMS twisters taken as reference, showed that analyte logK(o/w) is a key-factor driving the choice of the most effective coating. The new twisters showed to be successful for both SBSE and HSSE, although to a different extent. EG twisters gave high recoveries with analytes over a wide range of polarities and in particular with logK(o/w) below 2 and/or containing hydroxyl or carboxylic functional groups independently on their logK(o/w). On the other hand, PA twisters were selectively effective for highly polar compounds with logK(o/w) below 1.
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Via P. Giuria 9, I-10125 Torino, Italy. barbara.sgorbini@unito.it
authors.forename: Barbara
authors.initials: B
authors.lastname: Sgorbini
authors.forename: Cecilia
authors.initials: C
authors.lastname: Cagliero
authors.forename: Chiara
authors.initials: C
authors.lastname: Cordero
authors.forename: Erica
authors.initials: E
authors.lastname: Liberto
authors.forename: Patrizia
authors.initials: P
authors.lastname: Rubiolo
authors.forename: Manuela Rosanna
authors.initials: MR
authors.lastname: Ruosi
authors.forename: Carlo
authors.initials: C
authors.lastname: Bicchi
mesh_terms: D000327:Adsorption; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D014675:Vegetables / Q000737:chemistry*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon