Application of Self-Assembled Monolayers in the Preparation of Solid-Phase Microextraction Coatings

Abstract

Self-assembled monolayers (SAMs) of polyaminithiophenol (PATP) were used as a covalent bonded coating for solid-phase microextraction (SPME). Thiolated aniline-analog monomers (mixture of 2-and 3-aminothiophenols, 2/3-ATP) were anchored on the gold surface and then electropolymerized. Due to the strong S-Au bond, thiol-terminated coating on the gold surface was very stable. The proposed covalent bonded coating showed higher mechanical (re-usability up to 100 times) and thermal stability (up to 320°C) than non-covalent bonded polyaniline coating (re-usability up to 20 times and thermal stability up to 250°C). The extraction capability of the proposed fiber for the extraction of five polycyclic aromatic hydrocarbons (PAHs), including phenanthrene, anthracene, pyrene, 9,10-dimethylanthracene and benzo[a]anthracene was examined. The effects of different parameters influencing the extraction efficiency of analytes including extraction temperature, extraction time, ionic strength, stirring rate and sample volume were examined and optimized. Linear ranges of 1-250 lg L -1 for phenanthrene and anthracene, and 1-100 lg L -1 for the other compounds were obtained. Detection limits were in the range of 0.1-0.32 lg L -1 . Single fiber repeatability and fiber to fiber reproducibility were less than 8.9 and 15.8%, respectively. Seawater sample was analyzed as real sample and good recoveries (81-108%) were obtained for target analytes.

A strategy to enhance the thermal stability of a nanostructured polypyrrole-based coating for solid phase microextraction

“…One group of novel sorbents is chemically bonded sorbents. Chemically bonded carbon nanotubes on modified gold substrate [9], covalent bonded polyaminithiophenol on the gold substrate [10] and chemically bonded ionic liquid on the fused-silica substrate [11] are the examples of these novel sorbents. Conducting polymers [12][13][14][15], particularly polypyrrole (PPY) and its derivatives, are another group of new sorbents used up to now [16][17][18].…”

2 Solid-Phase Microextraction and Related Techniques

“…The thiolterminated coating on the gold surface was very stable due to the strong S-Au bond. The proposed covalently bonded coating showed higher mechanical (re-usability up to 100 times) and thermal stability (up to 320 °C) than a non-covalent bonded PANI coating which could be reused up to 20 times and its thermal stability was just below 250 °C (Mehdinia et al, 2011).…”

“…These properties could improve and bring new features which are currently difficult to achieve with bulk materials (Gómez-Hens et al, 2008). Recently some research groups tried to prepare nanomaterial-based SPME fibers (Mehdinia et al, 2006(Mehdinia et al, , 2011Cao et al, 2008;Rastkari et al, 2010;Zewe et al, 2010). An essential and rather important characteristic of sorbents is its surface area-to-volume ratio, with materials having long lengths and nano-to microscale diameters possessing high surface area-to-volume ratio (Huang et al, 2003).…”

Recent Advances in the Extraction of Polycyclic Aromatic Hydrocarbons from Environmental Samples

“…Examples of other materials that have been employed to fabricate SPME coatings for the extraction of PAHs include polyaminithiophenol (PATP) with Au coating [131], poly(3,4-ethylenedioxythiophene)@gold nanoparticles [132], crosslinked methyl methacrylate-polyhedral oligomeric silsesquioxane hybrid polymeric coating [106], nanostructured octadecyl silica [133] and polythiophene/carboxylic acid modified multi-walled carbon nanotube composite [134]. In the latter approach, the researchers developed a novel SPME technology, in which the features of heating the sample, cooling the sorbent and extraction under vacuum condition were combined [134].…”