Modeling solid-phase microextraction of volatile organic compounds by porous coatings using finite element analysis

Bulat Kenessov; Miras Derbissalin; Jacek A Koziel; Dmitry S Kosyakov

doi:10.1016/j.aca.2019.05.042

Modeling solid-phase microextraction of volatile organic compounds by porous coatings using finite element analysis

Anal Chim Acta. 2019 Oct 17:1076:73-81. doi: 10.1016/j.aca.2019.05.042. Epub 2019 May 25.

Authors

Bulat Kenessov¹, Miras Derbissalin², Jacek A Koziel³, Dmitry S Kosyakov⁴

Affiliations

¹ Center of Physical Chemical Methods of Research and Analysis, Faculty of Chemistry and Chemical Technology, Al-Farabi Kazakh National University, 050012, Almaty, Kazakhstan. Electronic address: bkenesov@cfhma.kz.
² Center of Physical Chemical Methods of Research and Analysis, Faculty of Chemistry and Chemical Technology, Al-Farabi Kazakh National University, 050012, Almaty, Kazakhstan. Electronic address: derbissalin@cfhma.kz.
³ Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, USA. Electronic address: koziel@iastate.edu.
⁴ Core Facility Center "Arktika", Northern (Arctic) Federal University, Arkhangelsk, Russia. Electronic address: d.kosyakov@narfu.ru.

PMID: 31203966
DOI: 10.1016/j.aca.2019.05.042

Abstract

Experimental optimization of analytical methods based on solid-phase microextraction (SPME) is a complex and labor-intensive process associated with uncertainties. Using the theoretical basics of SPME and finite element analysis software for the optimization proved to be an efficient alternative. In this study, an improved finite element analysis-based model for SPME of volatile organic compounds (VOCs) by porous coatings was developed mainly focussing on the mass transport in coatings. Benzene and the Carboxen/polydimethylsiloxane (Car/PDMS) coating were used as the model VOC and a porous SPME coating, respectively. It has been established that in the coating, volumetric fractions of Carboxen, PDMS, and air are 33, 42 and 24%, respectively. Knudsen diffusion in micropores can slow down a mass transport of analytes in the coating. When PDMS was considered as the solid part of the coating, lower root-mean-square deviation of the modeling results from experimental data was observed. It has been shown that the developed model can be used to model the extraction of VOCs from air and water samples encountered in a typical SPME development method procedure. It was possible to determine system equilibration times and use them to optimize sample volume and Henry's law constant. The developed model is relatively simple, fast, and can be recommended for optimization of extraction parameters for other analytes and SPME coatings. The diffusivity of analytes in a coating is an important property needed for improved characterization of existing and new SPME polymers and analytical method optimization.

Keywords: Benzene; COMSOL Multiphysics; Carboxen; SPME; Transport in porous media; Volatile organic compounds.