Electrochemical preparation of poly(p-phenylenediamine-co-aniline) composite coating on a stainless steel wire for the headspace solid-phase microextraction and gas chromatographic determination of some derivatives of benzene

Polyaniline and Polyaniline-Based Materials as Sorbents in Solid-Phase Extraction Techniques

Polyaniline (PANI) is one of the best known and widely studied conducting polymers with multiple applications and unique physicochemical properties. Due to its porous structure and relatively high surface area as well as the affinity toward many analytes related to the ability to establish different types of interactions, PANI has a great potential as a sorbent in sample pretreatment before instrumental analyses. This study provides an overview of the applications of polyaniline and polyaniline composites as sorbents in sample preparation techniques based on solid-phase extraction, including conventional solid-phase extraction (SPE) and its modifications, solid-phase microextraction (SPME), dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (MSPE) and stir-bar sorptive extraction (SBSE). The utility of PANI-based sorbents in chromatography was also summarized. It has been shown that polyaniline is willingly combined with other components and PANI-based materials may be formed in a variety of shapes. Polyaniline alone and PANI-based composites were successfully applied for sample preparation before determination of various analytes, both metal ions and organic compounds, in different matrices such as environmental samples, food, human plasma, urine, and blood.

Arbitrary deformable and high-strength electroactive polymer/MXene anti-exfoliative composite films assembled into high performance, flexible all-solid-state supercapacitors

Flexible all-solid-state supercapacitors (ASSSs) are excellent energy storage devices for portable/wearable electronics, although the development of an excellent comprehensive performance film electrode for the extraordinary flexible ASSSs still faces a great challenge. Here, bendable, foldable and anti-exfoliative Ti3C2Tx MXene-based films utilized as supercapacitor electrodes are reported. Polyaniline/Ti3C2Tx composites (i-PANI@Ti3C2Tx) were prepared by in situ oxidant-free polymerization of aniline on Ti3C2Tx nanosheets with p-phenylenediamine (PPD) as an initiator. Lignosulfonate (Lig) and Ti3C2Tx were constructed into a compact composite (Lig@Ti3C2Tx) film based on the hydrogen bonds formed between Lig and Ti3C2Tx. The Lig@Ti3C2Tx/i-PANI@Ti3C2Tx(5/5) hybrid film was produced by vacuum-assisted filtration of the mixed two composite dispersions. The as-prepared films can be arbitrarily deformed (such as bending and folding). They show high tensile strength and vertical-plane (the plane of film) tensile strength with 33.2 and 0.28 MPa for the i-PANI@Ti3C2Tx film, 75.4 and 0.77 MPa for the Lig@Ti3C2Tx film, and 53.7 and 0.58 MPa for the Lig@Ti3C2Tx/i-PANI@Ti3C2Tx(5/5) film (those of Ti3C2Tx film are 17.4 and 0.21 MPa), respectively. The enhanced vertical-plane tensile strength of the as-prepared composite films indicates that the large binding force generated between the Ti3C2Tx nanosheets can effectively prevent the exfoliation of films. The electrodes of the as-prepared i-PANI@Ti3C2Tx, Lig@Ti3C2Tx and Lig@Ti3C2Tx/i-PANI@Ti3C2Tx(5/5) films assembled into symmetric flexible ASSSs can deliver excellent specific capacitances of 310 F g-1 (∼1001 F cm-3), 271 F g-1 (∼881 F cm-3) and 295 F g-1 (∼959 F cm-3), respectively. In addition, the corresponding supercapacitors exhibit ultrahigh energy densities of 34.8, 30.6 and 33.3 W h L-1, respectively. It is expected that the as-prepared MXene-based films can be applied in various fields, such as electromagnetic-interference shielding and batteries. Furthermore, the as-prepared flexible ASSSs can be practically used as a wearable energy storage device.

Facile in situ fabrication of oriented titania submicrorods embedded into a superelastic nickel–titanium alloy fiber substrate and their application in solid-phase microextraction

A novel NiTi@TiO₂SR fiber was fabricated on a NiTi fiber substrate after annealing for the determination of PAHs in water.

An ionic liquid doped electrochemical copolymer coating of indole and 3-methylthiophene for the solid-phase microextraction of polycyclic aromatic hydrocarbons

Poly(indole-co-3-methylthiophene)-ionic liquid (P(In–3-MeT)/IL) composite film was electrodeposited on a stainless steel wire for SPME.

Determination of ultra-trace amounts of chlorophenols in rain, tap and river water by an electrochemically controlled in-tube solid phase microextraction method

A nanostructured copolymer coating consisting of PPy doped with Naf was electrochemically synthesized on the inner surface of a stainless steel capillary tube. It was utilized to extract trace pollutants from water samples.

Ordered mesoporous carbon/Nafion as a versatile and selective solid-phase microextraction coating

In this study, ordered mesoporous carbon (OMC) with large surface area (1019m(2)g(-1)), uniform mesoporous structure (pore size distribution centering at 4.2nm) and large pore volume (1.46cm(3)g(-1)) was synthesized using 2D hexagonally mesoporous silica MSU-H as the hard template and sucrose as the carbon precursor. The as-synthesized OMC was immobilized onto a stainless steel wire using Nafion as a binder to prepare an OMC/Nafion solid-phase microextraction (SPME) coating. The extraction characteristics of the OMC/Nafion coating were extensively investigated using a wide range of analytes including non-polar (light petroleum and benzene homologues) and polar compounds (amines and phenols). The OMC/Nafion coating exhibited much better extraction efficiency towards all selected analytes than that of a multi-walled carbon nanotubes/Nafion coating with similar length and thickness, which is ascribed to its high surface area, well-ordered mesoporous structure and large pore volume. When the OMC/Nafion coating was used to extract a mixture containing various kinds of analytes, it possessed excellent extraction selectivity towards aromatic non-polar compounds. In addition, the feasibility of the OMC/Nafion coating for application in electrochemically enhanced SPME was demonstrated using protonated amines as model analytes.