Layer‐by‐layer self‐assembly of a novel covalent organic frameworks microextraction coating for analyzing polycyclic aromatic hydrocarbons from aqueous solutions via gas chromatography

Abstract

In this study, a new covalent organic framework, consisting of tetra(4‐aminophenyl)porphyrin and tris(4‐formyl phenyl)amine, was layer‐by‐layer immobilized on stainless‐steel wire as a coating for microextraction. The fabrication process was easy and controllable under mild conditions. The as‐grown fiber was applied to extract polycyclic aromatic hydrocarbons in aqueous solution via head‐space solid‐phase microextraction. Furthermore, it was analyzed by gas chromatography with a flame ionization detector. A wide linear range (0.1–50 µg/L), low limits of detection (0.006–0.024 µg/L, signal‐to‐noise ratio = 3), good repeatability (intra‐fiber, n = 6, 3.1–8.50%), and reproducibility (fiber to fiber; n = 3, 5.79–9.98%), expressed as relative standard deviations, demonstrate the applicability of the newly developed coating. This new material was successfully utilized in real sample extraction with a satisfactory result. Potential parameters affecting the extraction efficiency, including extraction temperature and extraction time, salt concentration, agitation speed, sample volume, desorption temperature, and time, were also optimized and discussed.

Covalent Organic Framework Composites: Synthesis and Analytical Applications

“…Recently, in situ room-temperature fabrication of TFPB-BD-bonded fiber was reported [69], where an APTES-functionalized stainless-steel wire was treated with one of the COF building blocks, TFPB, and subsequently immersed in a solution containing the other COF building block, BD, and the catalyst acetic acid, leaving the reaction to continue for 3 days at room temperature. In addition, in a layer-by-layer approach [70], the APTES-functionalized stainless-steel wire was immersed alternately in building block solutions containing the organic solvent and the corresponding catalyst. After repeating the process until a desirable thickness (≈5 µm) was reached, the coating was cured by thermal treatment.…”

“…In this approach, the SPME fiber is exposed to the headspace above the sample avoiding direct contact with the sample and thus minimizing the effects associated with interferences present in the sample matrix. To date, different COF-coated fibers have been applied for the HS-SPME of semivolatile analytes, such as pyrethroids [126], polychlorinated biphenyls [69,127], PAHs [70,128], and phthalate esters [46,129] from vegetable, fruit, soil, and water samples. Furthermore, derivatization can be performed to extract non-volatile analytes.…”

“…The novel SPME fiber was applied for the extraction of polychlorinated biphenyls in fish and seafood, reaching detection limits in the range of 0.07-0.35 ng•L −1 . In another study, TFPA-TAPP-coated stainless steel fiber was obtained using a layer-by-layer strategy under mild conditions [70], and the as-grown fiber was applied to extract PAHs from water samples by HS-SPME achieving detection limits of 0.006-0.024 µg•L −1 .…”

β‐Ketoenamine‐linked covalent organic framework absorbent for online micro‐solid phase extraction of trace levels bisphenols in plastic samples

“…To date, imine-linked COFs are the most widely used in various fields. Especially in the application of sample preparation, imine-linked COFs have been already applied as extraction media for SPE [5], magnetic SPE (MSPE) [6], and SPME to successfully accomplish the efficient extraction of chemical pollutants such as pyrethroids [7], bisphenols (BPs) [8], polycyclic aromatic hydrocarbons (PAHs) [9], pesticide residues [10], and perfluorinated compounds [11]. Among the multifarious imine-linked COFs, TpPa-1 is a β-ketoenamine-linked novel porous COF formed by using 1,3,5-triformylphloroglucinol (Tp) and paraphenylenediamine (Pa-1) as building blocks based on the Schiff-base reaction, which possessed higher thermochemical stability and good hydrolytic resistance [12].…”

A thin‐layer solid‐phase extraction–liquid film elution technique used for the enrichment of polycyclic aromatic hydrocarbons in water

“…Since the sensitivity of the analytical procedure depends on the amount of analyte introduced into the detection instrument, efforts to improve the extraction efficiency have continued. One attempt is to introduce novel fiber coating materials, such as covalent organic frameworks [57], carbon nanospheres [58], and worm-like nickel-titanium oxide nanocomposites [59], that aim to increase the affinity of the extraction phase to the analyte or increase the specific surface area of the porous sorbent, as described in detail in a review article [60]. The other is to introduce an expanded surface area geometry in the coating substrate such as an SPME arrow [61][62][63], thin-film SPME [64][65][66], stir bar sorptive extraction [67,68], and lab-on-a-chip extraction [69].…”