New medium-to-high polarity twister coatings for liquid and vapour phase sorptive extraction of matrices of vegetable origin
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- 作者：Barbara Sgorbini ; barbara.sgorbini@unito.it ; Cecilia Cagliero ; Chiara Cordero ; Erica Liberto ; Patrizia Rubiolo ; Manuela Rosanna Ruosi ; Carlo Bicchi
- 关键词：Twisters ; Polar coatings ; HSSE ; SBSE ; Matrices of vegetable origin ; Log ; Ko/w
- 刊名：Journal of Chromatography A
- 出版年：2012
- 出版时间：23 November, 2012
- 年：2012
- 卷：1265
- 期：Complete
- 页码：39-45
- 全文大小：532 K
文摘
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 log Ko/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 log Ko/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 log Ko/w below 2 and/or containing hydroxyl or carboxylic functional groups independently on their log Ko/w. On the other hand, PA twisters were selectively effective for highly polar compounds with log Ko/w below 1.