Fabrication of polyaniline‐coated halloysite nanotubes by in situ chemical polymerization as a solid‐phase microextraction coating for the analysis of volatile organic compounds in aqueous solutions

Abstract

We have synthesized an organic-inorganic polyaniline-halloysite nanotube composite by an in situ polymerization method. This nanocomposite is immobilized on a stainless-steel wire and can be used as a fiber coating for solid-phase microextraction. It was found that our new solid-phase microextraction fiber is an excellent adsorbent for the extraction of some volatile organic compounds in aqueous samples in combination with gas chromatography and mass spectrometry. The coating can be prepared easily, is mechanically stable, and exhibits relatively high thermal stability. It is capable of extracting phenolic compounds from water samples. Following thermal desorption, the phenols were quantified by gas chromatography with mass spectrometry. The effects of extraction temperature, extraction time, sample ionic strength, stirring rate, pH, desorption temperature and desorption time were studied. Under optimal conditions, the repeatability for one fiber (n = 5), expressed as the relative standard deviation, is between 6.2 and 9.1%. The detection limits range from 0.005 to 4 ng/mL. The method offers the advantage of being simple to use, with a shorter analysis time, lower cost of equipment and higher thermal stability of the fiber in comparison to conventional methods of analysis.

Fiber‐in‐tube solid‐phase microextraction of caffeine as a molecular tracer in wastewater by electrochemically deposited layered double hydroxide

“…The polyaniline coated tube and wires were used for electrochemical deposition of layered double hydroxide according to the above-mentioned procedure and conditions described in the literature [32]. Briefly, the layered double hydroxide film was deposited on the surface by electrochemical reduction at applied potential of 0.90 V versus saturated calomel electrode in the solution containing nitrate salts of the divalent metal (M(II) = Zn), and trivalent metal (M(III) = Al) at the concentration of 0.0225 and 0.0075 mol/L for Zn(NO 3 ) 3 and Al(NO 3 ) 3 , respectively; 0.3 mol/L KNO 3 as the supporting electrolyte was used and deposition time was 10 min. The growth of the film was controlled based on the amount of charge consumed in the electropolymerization [33].…”

“…In fact, like all sorption‐based extraction methodologies, coating material of the fiber is a major factor for controlling the selectivity, capacity, sensitivity, and reusability. Hence, there is an ongoing research area for the development of the new coating material for the extraction of different target analytes . The basic objective is to develop more stable coatings with high extraction capacity toward the target analytes .…”

Emerging materials for sample preparation

“…Direct immersion SPME followed by GC with corona discharge ion mobility spectrometry was used for the determination of organophosphorus pesticides in aqueous samples. In a different study halloysite, characterized by its tubular structure, was combined with PANI to prepare a composite that was then used as an SPME device for the extraction of volatile phenols from water samples before GC–MS .…”

Fabrication of a novel hydrophobic/ion‐exchange mixed‐mode adsorbent for the dispersive solid‐phase extraction of chlorophenols from environmental water samples

“…The analysis of trace CPs in environmental samples usually requires a sample pretreatment step before instrumental determination. Several techniques have been applied in the pretreatment of CPs in water, such as SPE , SPME , dispersive solid‐phase extraction (d‐SPE) , magnetic SPE , molecularly imprinted SPE , and stir bar sorptive extraction . Among these techniques, adsorbent material is the key factor, which largely affects the adsorption performance in SPE procedure.…”