Layer-by-Layer Fabrication of Chemical-Bonded Graphene Coating for Solid-Phase Microextraction

Abstract

A new fabrication strategy of the graphene-coated solid-phase microextraction (SPME) fiber is developed. Graphite oxide was first used as starting coating material that covalently bonded to the fused-silica substrate using 3-aminopropyltriethoxysilane (APTES) as cross-linking agent and subsequently deoxidized by hydrazine to give the graphene coating in situ. The chemical bonding between graphene and the silica fiber improve its chemical stability, and the obtained fiber was stable enough for more than 150 replicate extraction cycles. The graphene coating was wrinkled and folded, like the morphology of the rough tree bark. Its performance is tested by headspace (HS) SPME of polycyclic aromatic hydrocarbons (PAHs) followed by GC/MS analysis. The results showed that the graphene-coated fiber exhibited higher enrichment factors (EFs) from 2-fold for naphthalene to 17-fold for B(b)FL as compared to the commercial polydimethylsioxane (PDMS) fiber, and the EFs increased with the number of condensed rings of PAHs. The strong adsorption affinity was believed to be mostly due to the dominant role of π-π stacking interaction and hydrophobic effect, according to the results of selectivity study for a variety of organic compounds including PAHs, the aromatic compounds with different substituent groups, and some aliphatic hydrocarbons. For PAHs analysis, the graphene-coated fiber showed good precision (<11%), low detection limits (1.52-2.72 ng/L), and wide linearity (5-500 ng/L) under the optimized conditions. The repeatability of fiber-to-fiber was 4.0-10.8%. The method was applied to simultaneous analysis of eight PAHs with satisfactory recoveries, which were 84-102% for water samples and 72-95% for soil samples, respectively.

Recent advances in solid-phase sorbents for sample preparation prior to chromatographic analysis

“…Carbon exists in a number of allotropic forms, such as fullerenes, CNTs, including single-walled CNTs (SWCNTs) and multi-wall CNTs (MWCNTs), carbon nanohorns, carbon nanocones, carbon nanodisks, carbon nanofibers, nanotube rings, graphene oxide (GO) and graphene (G), and diamonds [22][23][24][25][26]. However, to date, from the analytical point of view, the applications have mainly been focused on the use of fullerenes, CNTs and GO/G.…”

“…It possesses most of the advantages of CNTs. Moreover, it is prepared from graphite without any residual heterogeneous materials, which usually include residual metallic impurities and NPs derived from catalysts [25]. As a result, G is currently a popular option for SPSs.…”

Graphene oxide/Fe3O4 as sorbent for magnetic solid-phase extraction coupled with liquid chromatography to determine 2,4,6-trinitrotoluene in water samples

“…In addition, its electron delocalization system can form π-π bonds with benzene rings. Thanks to these particular properties, graphene can be used for adsorbing aromatic compounds [ 4,5,6,7,8 ]. The chemical synthesis of graphene commonly follows the Hummers method [ 9 ], consisting of the oxidation of graphite to form graphene oxide (GO) followed by the chemical reduction of GO to graphene using a reducing agent such as hydrazine.…”

“…Hydrophilic functional groups, such as hydroxyl and carbonyl, increase the affinity of graphene with polar compounds [ 4 ]. Miniaturization of the SPE technique includes the solid-phase microextraction (SPME) technique which also used graphene as adsorbent coating of the fibers [ 5,6,7,8,15 ]. However, the use of fiber as adsorbent has disadvantages such as its fragility, the reduced amount of adsorbent phase, its high cost, and possible memory effects [ 16 ].…”

Preparation and evaluation of mesoporous cellular foams coating of solid-phase microextraction fibers by determination of tetrabromobisphenol A, tetrabromobisphenol S and related compounds

“…For new coating materials, high-porosity materials have attracted much attention recently because of their large specific surface areas and high extraction capacities resulting in significant improvement in sensitivity, such as carbon nanotubes [15], graphene [16,17] and metal-organic framework [7]. Mesoporous materials are considered the high-efficiency sorbents due to high specific surface area, controllable pore size, narrow pore size distribution, thermal and mechanical stability, which have various applications in chemical industry [18,19], environment [10,[18][19][20], medicine [21,22], adsorption and separation [23].…”