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A new organic-inorganic hybrid coated titanium fibre was developed via self-assembled modification for rapid and efficient solid-phase microextraction (SPME). Oriented titania nanorods (TiO2NRs) were in situ grown on the Ti wire as a fibre substrate through direct electrochemical anodisation. Subsequently, dodecyl groups were chemically bonded to the surface of TiO2NRs via self-assembly of n-dodecyltrimethoxysilane. The dodecyl-functionalised TiO2NRs coated Ti fibre was used to extract representative aromatic compounds coupled to high-performance liquid chromatography with UV detection. The new fibre exhibited excellent extraction efficiency and selectivity for the studied polycyclic aromatic hydrocarbons (PAHs) compared to commercial polydimethylsiloxane and polyacrylate fibres. The influential factors affecting the SPME process of PAHs were investigated and optimised. Under the optimised conditions, the developed method presented dynamic linear ranges from 0.03 to 500 μg·L−1 with correlation coefficients higher than 0.999 and limits of detection from 0.006 to 0.57 μg·L−1. Relative standard deviations (RSDs) varied between 3.51% and 4.93% and between 4.17% and 5.23% for intra-day and inter-day measurements with one single fibre, respectively. RSDs for the fibre-to-fibre reproducibility from 4.26% to 8.65% were achieved. The developed method was successfully applied to the selective preconcentration and determination of target PAHs in different environmental water samples. The relative recoveries from 89.62% to 113.1% were obtained with RSDs below 8.53%. Moreover, this fibre can be used over 200 times and fabricated in a precisely controllable manner. [ABSTRACT FROM AUTHOR]

With titanium wire as a titanium source and a fiber substrate, titania nanostrips (TiO2NSs) were in situ grown on the fiber surface by electrochemical anodization and used as supporting templates for subsequent uniform deposition of polar glucose via hydrothermal reaction. After annealing, controllable in situ derivation of TiO2NSs-templated carbonaceous coating (TiO2@CNSs) was achieved on the Ti fiber substrate. Coupled to high-performance liquid chromatography with UV detection, the extraction performance was investigated using representative aromatic compounds as model analytes and compared with those of commercially available fibers. The results demonstrated that the Ti@TiO2@CNSs fiber exhibited good extraction selectivity for PAHs, especially for high-molecular-weight PAHs. For this purpose, the key parameters affecting extraction efficiency of PAHs were optimized. Under optimized conditions, linearity was shown in the ranges of 0.02–200 μg·L−1 with the correlation coefficients of greater than 0.999. Limits of detection were 0.005–0.056 μg·L−1. The intra-day and inter-day repeatability of the proposed method with the single fiber varied from 2.06% to 3.99% and from 2.85% to 5.17%, respectively. The fiber-to-fiber reproducibility ranged from 2.86% to 5.21%. The proposed method was successfully applied to selective preconcentration and sensitive determination of target PAHs in real water samples. Moreover, this fiber has a long service time. [ABSTRACT FROM AUTHOR]

A new strategy was proposed for the electrochemical fabrication of manganese dioxide (MnO2) coatings on titanium (Ti) fibers. In order to achieve stable MnO2 coatings, a Ti wire was initially anodized in methanol/water containing fluoride ions for the in situ growth of nano/submicro-scale titania (TiO2) pyramids. Thereafter, silica nanoparticles (SiO2NPs) were electrophoretically deposited on the TiO2 coatings. Finally, the nanoparticle-like MnO2 coating was homogeneously formed on the Ti@TiO2@SiO2NPs fiber support in neutral electrolytic solution by cyclic voltammetry using polypyrrole as an organic binder. The resulting fiber showed good extraction selectivity and efficient extraction capability for aromatic compounds with large delocalized π-systems. For this purpose, this fiber was used for the selective enrichment of the studied polycyclic aromatic hydrocarbons (PAHs) coupled to high-performance liquid chromatography with ultraviolet detection. The linear calibration curves were obtained in the concentration range of 0.01–500 μg L−1 with correlation coefficients higher than 0.999 in all instances. The relative standard deviations (RSDs) for single fiber repeatability varied from 4.7% to 5.5% for intra-day and inter-day measurements (n = 5), and RSDs for the fiber-to-fiber reproducibility varied from 5.8% to 6.7% (n = 5). The developed method was successfully applied to the selective enrichment and sensitive determination of target PAHs in river water, rain water and wastewater samples with relative recoveries from 93.0% to 106%. Furthermore, the fabricated fiber was stable enough to perform the whole analytical sequence in practical applications. [ABSTRACT FROM AUTHOR]

A novel and robust phenyl-functionalized MSU-1 (Ph-MSU) coated fiber for solid-phase microextraction (SPME) coupled to high performance liquid chromatography (HPLC) was developed for the preconcentration and the determination of 2,4,4′-trichlorobiphenyl (PCB 28), 2,4′,5-trichlorobiphenyl (PCB 31), 2,2′,5,5′-tetrachlorobiphenyl (PCB 52), 2,2′,4,5,5′-pentachlorobiphenyl (PCB 101), 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118), 2,2′,3,4,4′,5′-hexachlorobiphenyl (PCB 138), 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153), and 2,2′,3,4,4′,5,5′-heptachlorobiphenyl (PCB 180) in environmental water samples. Experimental conditions affecting SPME were examined in detail. The Ph-MSU coating provided large porosity and short-range mesostructures necessary for high extraction capacity and rapid mass transfer of PCBs. The Ph-MSU coated fiber exhibited selectivity for PCB 28, PCB 31, PCB 118, and PCB 138 in a limited extraction time. Good linearity for all PCBs was obtained with correlation coefficients from 0.9987 to 0.9994. The recoveries were within 94.3% to 103% for the spiked water with 300 ng · L−1per PCB. The relative standard deviations (RSDs) ranged from 3.10% to 6.23% and the limits of detection (LODs) were between 8.73 ng · L−1and 13.8 ng · L−1. The proposed method was applied for the determination of PCBs in real river water and rainwater samples. The median recoveries ranged from 85.6% to 118% with RSDs between 4.23% and 8.78%. The experimental results demonstrated that the Ph-MSU fiber coating could be reused for over 250 times without loss of the extraction efficiency. These results clearly indicate that the Ph-MSU coated fiber was rapid, sensitive, and suitable for the preconcentration and determination of trace PCBs in environmental water samples. [ABSTRACT FROM AUTHOR]

Nickel-titanium oxide nanotubes (NiTiONTs), nanoparticles, and nanopores were in situ grown on NiTi fiber substrates by controlling anodization parameters. The adsorption performance of different bimetallic oxide nanostructures was evaluated using typical aromatic compounds including chlorophenols, phthalic acid esters, ultraviolet filters (UVFs), and polycyclic aromatic hydrocarbons (PAHs) coupled to HPLC-UV. The results clearly indicate that these NiTiO nanostructures show good extraction capability for UVFs and PAHs. The extraction performance of UVFs and PAHs greatly depends on the surface morphologies and sizes of the grown NiTiO nanostructures along with their elemental compositions. Compared with NiTiO nanoparticle and nanopore coatings, the longer well-aligned NiTiONT coating exhibits better extraction capability and selectivity for PAHs than for UVFs. Therefore, the extraction parameters of the NiTi@NiTiONT fiber for PAHs were investigated and optimized. Under optimized conditions, the proposed method was linear in the range 0.05–200 μg L−1 with correlation coefficients above 0.999. Limits of detection were between 0.008 and 0.124 μg L−1. Relative standard deviations (RSDs) of the intra-day and the inter-day analyses with the single fiber varied from 4.09 to 6.33%. RSDs for fiber-to-fiber reproducibility of the proposed method with five fibers prepared in different batches were between 5.75 and 7.43%. The applicability of the proposed method was investigated by the enrichment and determination of target PAHs in environmental water samples and relative recoveries of 84.5 ± 6.5 – 116 ± 7.8% were achieved. Notably, the prepared fiber was stable up to 250 times. [ABSTRACT FROM AUTHOR]

The authors describe TiO2 nanowires (TiO2NWs) for solid-phase microextraction of polycyclic aromatic hydrocarbons (PAHs). Well-oriented TiO2NWs were in-situ grown on a titanium wire by a hydrothermal process. The TiO2NWs arrays are radially aligned on the curved titanium fiber substrate. They possess a large surface area and are readily accessible for subsequent self-assembly of trichlorophenylsilane via formation of Ti-O-Si bonds. The TiO2NWs coated fibers show good extraction selectivity for PAHs as shown for phenathrene, fluoranthene, pyrene and benzo[a]pyrene. Following desoption by mobile phases for HPLC analysis, the PAHs were quantified by HPLC with UV detection. The improved extraction capabilities and good selectivity are explained by synergistic hydrophobic and π stacking interactions between the phenyl moieties and the PAHs. Key parameters that affect the extraction performance of the fibers were optimized. The method has a linear response in the 0.1 to 200 μg·L−1 PAH concentration range. Limits of detection (at S/N = 3) range from 20 to 50 ng·L−1. Relative standard deviations (RSDs) for the single fiber repeatability are less than 7.3% (n = 5) and RSDs for the fiber-to-fiber reproducibility are below 8.1% (n = 5). The method was successfully applied to the selective preconcentration and determination of trace PAHs in spiked water samples. [ABSTRACT FROM AUTHOR]

Phenolic compounds (PCs) are a class of polar aromatic pollutants with high toxicity in environmental water. Generally the efficient sample preparation is essential for the quantification of ultra-trace target PCs in real water sample before appropriative instrumental analysis. SPME is a convenient, solvent-free and time-saving miniaturized technique and has been recognized as a green alternative to conventional extraction techniques. In SPME, however, commercial fused-silica fibers are limited to the fragility, operation temperature, extraction capacity and selectivity as well as lifetime. Therefore, the development of new SPME fibers is always needed to overcome such limitations. We presented a novel top-down strategy for in situ construction of vertically oriented hexagonal sulfate intercalated NiCr layered double hydroxide nanosheet arrays (NiCr LDHs-SO 4 NSAs) on the Nichrome (NiCr) substrate by hydrothermal treatment in NaOH solution containing (NH 4) 2 S 2 O 8. The results showed that much shorter hydrothermal time was needed for the construction of NiCr@NiCr LDHs-SO 4 NSAs fiber in the presence of (NH 4) 2 S 2 O 8. Moreover, the unique NiCr LDHs-SO 4 NSAs coating offered open access structure, and thereby more available surface area for adsorption. The resulting fiber exhibited better extraction efficiency for phenolic compounds (PCs), faster mass transfer rate, higher mechanical stability, and longer service life than original NiCr@NiCr LDHs NSs fiber and typical commercially fused-silica fibers. After optimizing conditions, the SPME-HPLC-UV method demonstrated a linear range from 0.05 μg L−1 to 200 μg L−1 with LODs of 0.015–0.156 μg L−1 (S/N = 3) and LOQs of 0.048–0.498 μg L−1 (S/N = 10), as well as good repeatability (3.06%–5.22%) and fiber-to-fiber reproducibility (4.32%–6.49%). The developed SPME-HPLC-UV method with the constructed fiber was applied to the preconcentration and detection of different types of PCs in real water samples, showing satisfactory recoveries ranging from 86.20% to 107.8% with RSDs of 3.18%–6.69%. This study provides a new strategy for in situ construction of bimetallic hydroxides and their derived nanocomposite coatings on the NiCr fiber substrate in practical SPME application. Schematic illustration for the construction and application of the NiCr@NiCr LDHs-SO 4 NSAs fiber. [Display omitted] • Novel ultrathin hexagonal NiCr LDHs-SO 4 NSAs were in situ constructed on the flexible NiCr fiber. • Persulfate not only greatly reduced the reaction time, but also SO 4 2− as intercalation anions in the formation of NSAs. • The NiCr@NiCr LDHs-SO 4 NSAs fiber showed high stability and long service life. • The constructed fiber demonstrated superior extraction capability and good selectivity for PCs. • The developed fiber was successfully applied to selective enrichment and determination of target PCs in water. [ABSTRACT FROM AUTHOR]

• A hollow Co-MOF-74 incorporated electrospun nanofiber membranes (H-NFMs) were fabricated. • The H-NFMs were installed in a homemade filter to remove PAHs by the drain-type adsorption. • Hydrophobic H-NFMs have good mechanical, fast mass transfer capability, and favorable regeneration properties. • The method provided a new, effective and low-cost strategy for rapid and superior removal of PAHs. Developing efficient adsorbents for the removal of polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions is an attractive and significative task. Herein, we demonstrate a route to fabricate hollow Co-MOF-74 incorporated electrospun nanofiber membranes and combine it with a homemade filter device for drain-type adsorption to remove PAHs from aqueous solutions. The removal efficiency of the prepared H-NFMs were more than 80% (except B[ghi]p = 75%), and exhibited excellent reusability for multiple regeneration cycles. In addition, the introduced H-Co-MOF-74 material possessed a large surface area (633.6 m2 g−1) and hollow structure, which could supply more exposed adsorption active sites, accelerate mass transfer and shorten the adsorption equilibrium time. By loading H-Co-MOF-74 in nanofiber membranes, H-NFMs have high hydrophobicity, good mechanical and thermal stability, while the filters and membranes can be easily recycled separately after the adsorption is completed. This study not only proposed a simple and rapid adsorption method of an efficient sorbent material but also provided an ingenious separation and removal strategy for other pollutants in aqueous solutions. [ABSTRACT FROM AUTHOR]

The flower-like hierarchical cobalt nickel oxide nanoflakes (CoNiO 2 NFs) with a porous structure were fabricated on Nitinol (NiTi) fiber substrate by a hydrothermal reaction and subsequent annealing treatment. The morphology affected by the molar ratios of Ni to Co and counter ions in starting precursors as well as hydrothermal reaction temperature and time was investigated in detail. The obtained CoNiO 2 NFs coating exhibited outstanding performance for the selective extraction of PAHs. After optimizing the main parameters that affected extraction through orthogonal experiments, the developed method showed good linearity in the ranges of 0.05 μg L−1 - 200 μg L−1 with the determination coefficient >0.999. LODs were between 0.006 μg L−1 and 0.114 μg L−1, LOQs were in the ranges of 0.020–0.376 μg L−1 and RSDs were below 5.19% and 5.71% for intra-day and inter-day analyses, respectively. The developed method was successfully applied to selective enrichment and determination of target PAHs in real water samples. Moreover, the fabricated fiber exhibited high chemical and mechanical stability, and could withstand more than 260 extraction-desorption cycles without loss of its extraction efficiency. Schematic diagram for the step-wise fabrication and application of the NiTi@CoNiO 2 NFs fiber. [Display omitted] • The 3D flower-like hierarchical CoNiO 2 NFs were in situ grown on NiTi fiber substrate. • The morphology and extraction performance of the CoNiO 2 NFs could be tuned. • The hierarchical CoNiO 2 NFs coating showed superior extraction selectivity for PAHs. • The fabricated fiber exhibited high chemical and mechanical stability. • The developed method was applied to enrichment and detection of PAHs in real water. [ABSTRACT FROM AUTHOR]

Abstract: Two kinds of mesoporous cellular foams (MCFs), including mesoporous silica materials (MCF-1) and phenyl modified mesoporous materials (Ph-MCF-1), were synthesized and for the first time used as fiber-coating materials for solid-phase microextraction (SPME). By using stainless steel wire as the supporting core, four types of fibers were prepared by sol–gel method and immobilized by epoxy-resin method. To evaluate the performance of the home-made fibers for SPME, seven brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS) and related compounds were selected as analytes. The main parameters that affect the extraction and desorption efficiencies, such as extraction temperature, extraction time, desorption time, stirring rate and ionic strength of samples were investigated and optimized. The optimized SPME coupled with high performance liquid chromatography (HPLC) was successfully applied to the determination of the seven BFRs in water samples. The linearity range was from 5.0 to 1000μgL−1 for each compound except TBBPS (from 1.0 to 1000μgL−1), with the correlation coefficients (r 2) ranging from 0.9993 to 0.9999. The limits of detection of the method were 0.4–0.9μgL−1. The relative standard deviations varied from 1.2 to 5.1% (n =5). The repeatability of fiber-to-fiber and batch-to-batch was 2.5–6.5% and 3.2–6.7%. The recoveries of the BFRs from aqueous samples were in the range between 86.5 and 103.6%. Compared with three commercial fibers (100μm PDMS, 85μm PA and 65μm PDMS/DVB), the MCFs-coated fiber showed about 3.5-fold higher extraction efficiency. [Copyright &y& Elsevier]

[Display omitted] • ZIF-67 derived hollow double-shelled Co 3 O 4 /carbon (HoMS-Co 3 O 4) were successfully prepared. • A novel spiral-solid phase microextraction (S-SPME) fiber using HoMS-Co 3 O 4 as coating was designed. • Open a new way for the preparation of hollow multishelled structure using ligand conversion method. • The proposed method provided a new, effective and low-cost method for rapid and superior capture PAHs. Here, a unique spiral-solid phase microextraction (S-SPME) fiber using ZIF-67 derived hollow multishelled structures Co 3 O 4 /carbon nanomaterials (HoMS-Co 3 O 4 /C) as the coating was designed for superior capture of trace polycyclic aromatic hydrocarbons (PAHs). The ligand 2-methylimidazole of ZIF-67 was replaced twice with 2,5-dihydroxyterephthalic acid and followed by pyrolysis to obtain the material with an unique hollow double-shelled structure. The formation of the hollow structure can be explained by the Ostwald ripening. Fifteen PAHs, four brominated flame retardants (BFRs), and seven endocrine chemicals (EDCs) were used to investigate the extraction performance of HoMS-Co 3 O 4 /C coated S-SPME fiber. The spiral fiber displayed higher selectivity for PAHs compared with BFRs and EDCs. The methods had low detection limits (0.002–2.680 μg L−1), wide linear ranges (0.005–1000 μg L−1), and good reproducibility (0.7–10.7%, fiber to fiber). In addition, the S-SPME fiber demonstrated excellent enrichment ability and extraction efficiency for PAHs compared with commercial SPME fibers, it might since there were strong π-π stacking force, hydrophobic interaction between analytes and HoMS-Co 3 O 4 /C coating, also the HoMS coating and the spiral fiber could greatly increase the contact area between adsorbent and target compounds. Finally, the HoMS-Co 3 O 4 /C coated S-SPME fiber had been further adopted to detect fifteen PAHs in environmental water samples successfully. [ABSTRACT FROM AUTHOR]

• Two kinds of TiO 2 nanowires (TiO 2 NWs) were in-situ grown on Ti substrates by the hydrothermal process. • The in-situ growth of TiO 2 NWs was precisely controllable. • The TiO 2 NWs coating grown at higher temperature within longer time showed higher affinity towards PAHs than that grown at lower temperature within shorter time. • The Ti@TiO 2 NWs-200 fiber was successfully applied to the detection of PAHs in real water samples. • The Ti@TiO 2 NWs-200 fiber displayed high mechanical and chemical stability along with long lifetime. Two kinds of TiO 2 nanowires (TiO 2 NWs) with different orientation were in-situ grown on Ti substrates by controlling temperature and time during the hydrothermal process. The adsorption performance was evaluated by using typical aromatic compounds as model analytes coupled to HPLC with UV detection. The results demonstrated that the TiO 2 NWs coating grown at higher temperature within longer time had better affinity towards PAHs. For this purpose, the key experimental factors affecting the adsorption performance of the TiO 2 NWs coating fabricated at 200 °C for 10 h were further investigated and optimized for the extraction of PAHs. Under the optimized conditions, the proposed method presented linear responses in the concentration ranges of 0.05 to 200 μg·L−1 PAHs with correlation coefficients more than 0.998. LODs (S/N=3) were 0.008 to 0.034 μg·L−1. Moreover, RSDs for the single fiber repeatability of the intra-day and the inter-day analyses were less than 5.6% (n =5) and 5.8%, respectively. RSDs for the fiber-to-fiber reproducibility were between 5.1% and 6.5%. Finally, the proposed method was successfully applied to the selective preconcentration and determination of trace PAHs in environmental water samples. In addition, The fabricated Ti fiber can be used at least 200 times due to its high mechanical and chemical stability. [ABSTRACT FROM AUTHOR]

A new flake-like zinc–aluminum layered double hydroxide (ZnAl-LDH) coating was firmly fabricated on a superelastic nickel–titanium alloy (NiTi) wire. Herein, the NiTi wire was hydrothermally treated for the in-situ growth of nickel and titanium oxide nanoflakes (NiTiONFs) and used as a fiber support for subsequent growth of ZnAl-LDH nanoflakes. The resulting coating was able to selectively extract the studied ultraviolet filters (UVFs) more effectively and quickly in comparison with the commercial polyacrylate and polydimethylsiloxane fibers. This fiber shows long recycling lifetime due to the ZnAl-LDH coating embedded into the active NiTiONFs support with high mechanical stability. For this purpose, main experimental parameters including temperature, stirring rate, extraction and desorption time, and ionic strength were investigated and optimized in detail. Under the optimized conditions, good linearity was obtained for the developed SPME–HPLC–UV method with the NiTi@NiTiONFs@ZnAl-LDH fiber. Limits of detection were between 0.009 μg L−1 and 0.052 μg L−1 for five UVFs. Intra-day and inter-day relative standard deviations (RSDs) for single fiber repeatability were less than 6.4% and 6.6% for five replicate extractions of UVFs at the spiking level of 50 μg L−1. RSDs for fiber-to-fiber reproducibility varied from 6.3% to 6.9%. The developed method was successfully used for the determination of UVFs in snow water, river water and wastewater samples. The relative recoveries of 80.1%–109% were achieved. Thus the developed method could be potentially applied to selective enrichment and determination of UVFs in different environmental water samples. ZnAl bimetallic nanoflake coating was grown on NiTiONFs surface by hydrothermal method. The developed SPME–HPLC method was successfully applied to the enrichment and detection of UVFs in environmental water samples. In addition, the fabricated fibers showed good fiber-to-fiber reproducibility and long recycling stability. Image, graphical abstract [ABSTRACT FROM AUTHOR]