Huiju Wang

Hydrothermally grown and self-assembled modified titanium and nickel oxide composite nanosheets on Nitinol-based fibers for efficient solid phase microextraction

A novel titanium and nickel oxide composite nanosheets (TiO2/NiOCNSs) coating was in situ grown on a Nitinol (NiTi) wire by direct hydrothermal treatment and modified by self-assembly of trichlorophenylsilane for solid phase microextraction (SPME). TiO2/NiOCNSs were radially oriented and chemically bonded to the NiTi substrate with double-faced open access sites. Moreover the phenyl modified TiO2/NiOCNSs (TiO2/NiOCNSs-Ph) coating exhibited original surface supporting framework favorable for effective SPME. The extraction performance of TiO2/NiOCNSs-Ph coated NiTi (NiTi-TiO2/NiOCNSs-Ph) fiber was investigated for the concentration and detection of ultraviolet (UV) filters, polycyclic aromatic hydrocarbons (PAHs), phthalate acid esters and polychlorinated biphenyls coupled to HPLC with UV detection. The novel fiber exhibited better selectivity for UV filters and PAHs and presented greater extraction capability compared to commercial polydimethylsiloxane and polyacrylate fibers. Under the optimized conditions for SPME of UV filters, the proposed method presented linear ranges from 0.1 to 300μg/L with correlation coefficients of higher than 0.999 and limits of detection from 0.030μg/L to 0.064μg/L. Relative standard deviations (RSDs) were below 7.16% and 8.42% for intra-day and inter-day measurements with the single fiber, respectively. Furthermore RSDs for fiber-to-fiber reproducibility from 6.57% to 8.93% were achieved. The NiTi-TiO2/NiOCNSs-Ph fiber can be used up to 200 times. The proposed method was successfully applied to the preconcentration and determination of trace target UV filters in different environmental water samples. The relative recoveries from 87.3% to 104% were obtained with RSDs less than 8.7%.

Rapid in situ growth of oriented titanium-nickel oxide composite nanotubes arrays coated on a Nitinol wire as a solid-phase microextraction fiber coupled to HPLC-UV.

An oriented titanium-nickel oxide composite nanotubes coating was in situ grown on a nitinol wire by direct electrochemical anodization in ethylene glycol with ammonium fluoride and water for the first time. The morphology and composition of the resulting coating showed that the anodized nitinol wire provided a titania-rich coating. The titanium-nickel oxide composite nanotubes coated fiber was used for solid-phase microextraction of different aromatic compounds coupled to high-performance liquid chromatography with UV detection. The titanium-nickel oxide composite nanotubes coating exhibited high extraction capability, good selectivity, and rapid mass transfer for weakly polar UV filters. Thereafter the important parameters affecting extraction efficiency were investigated for solid-phase microextraction of UV filters. Under the optimized conditions, the calibration curves were linear in the range of 0.1-300 μg/L for target UV filters with limits of detection of 0.019-0.082 μg/L. The intraday and interday precision of the proposed method with the single fiber were 5.3-7.2 and 5.9-7.9%, respectively, and the fiber-to-fiber reproducibility ranged from 6.3 to 8.9% for four fibers fabricated in different batches. Finally, its applicability was evaluated by the extraction and determination of target UV filters in environmental water samples.

Development of nitrogen-enriched carbonaceous material coated titania nanotubes array as a fiber coating for solid-phase microextraction of ultraviolet filters in environmental water

A novel solid-phase microextraction (SPME) fiber was fabricated by direct electrodeposition of polyaniline (PANI) coated the titania nanotube arrays in situ grown on the titanium wire followed by carbonization at 500°C under nitrogen atmosphere. The resulting titanium-based fiber with nitrogen-enriched carbonaceous material coated titania nanotubes (N-C/TiO2NTs/Ti) showed better extraction performance for ultraviolet (UV) filters among model aromatic compounds compared with common PANI as well as commercial polydimethylsiloxane and polyacrylate coatings. The influence of various experimental parameters on the extraction efficiency of UV filters were investigated and optimized. The calibration curves were linear from 0.2 to 200μgL-1 for each analyte with correlation coefficients above 0.9980. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.03 to 0.05μgL-1 and from 0.11 to 0.18μgL-1 for UV filters, respectively. Relative standard deviations (RSDs) for single fiber repeatability ranged from 3.3% to 4.1% (n=5) and RSDs for fiber-to-fiber reproducibility (n=3) varied from 5.7% to 7.7%. The proposed method was successfully applied to the preconcentration and determination of target UV filters in river water and wastewater samples with good recoveries from 86.2% to 113%. Moreover this novel Ti-based fiber is mechanically and chemically stable, and can be easily prepared in a highly reproducible manner.

Electrophoretic deposition strategy for the fabrication of highly stable functionalized silica nanoparticle coatings onto nickel-titanium alloy wires for selective solid-phase microextraction

A new strategy for the immobilization of phenyl-functionalized silica nanoparticles onto nickel-titanium alloy wires is presented. The homogeneous and compact silica nanoparticle coating was achieved on the hydrothermally treated nickel-titanium wires with large surface area by electrophoretic deposition, and followed by self-assembled modification of phenyltrichlorosilane. Coupled to high-performance liquid chromatography with ultraviolet detection, the extraction performance of the fabricated fiber was evaluated using typical aromatic compounds in direct-immersion mode of solid-phase microextraction. Due to its high extraction efficiency and good selectivity for ultraviolet filters, the novel fiber was employed to investigate the key factors affecting the extraction of ultraviolet filters. Under the optimized conditions, the proposed method presented linear ranges from 0.05 to 300 μg/L with correlation coefficients higher than 0.999 and limits of detection from 0.005 to 0.058 μg/L. Relative standard deviations were below 4.3 and 5.6% for intraday and interday analyses at the spiking level of 50 μg/L ultraviolet filters with the single fiber, respectively. The proposed method was successfully applied to the selective concentration and sensitive detection of target ultraviolet filters from environmental water samples. Furthermore, the developed fiber can be used at least 200 times, and fabricated in a precisely controllable manner.

Innovative fabrication of the flower-like nanocomposite coating on a nitinol fiber through Fenton’s oxidation for selective and sensitive solid-phase microextraction

A novel flower-like nanostructure was successfully in situ fabricated on the surface of nitinol wire through Fentons oxidation for the first time. It was found that the densely immobilized coating on the surface of the nitinol fiber was composed of nickel and titanium oxide nanocomposite (NiO/TiO2NC). The NiO/TiO2NC coated fiber was used to extract aromatic compounds coupled with high performance liquid chromatography (HPLC) with UV detection and exhibited excellent extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) with larger delocalized π-system among the studied analytes. Important factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0.05 to 500μgL(-1) with correlation coefficients of R(2)≥0.999, and the lowest limit of detection of 0.006μgL(-1) was achieved for benzo[a]pyrene. Furthermore, the intra-day and inter-day precisions for the single fiber varied from 4.69% to 5.97% and from 5.28% to 6.32% for five replicates of PAHs at the spiking level of 50μgL(-1), respectively. The fiber-to-fiber precision for five fibers prepared in different batches ranged from 6.19% to 8.35%. The developed method was successfully applied to concentration and determination of target PAHs from real environmental water samples. Moreover, this novel nitinol-based fiber exhibited long lifespan. Therefore, the proposed fiber can be used as a promising candidate for a conventional fused silica-based fiber in SPME.

Gold nanoparticle modified NiTi composite nanosheet coating for efficient and selective solid phase microextraction of polycyclic aromatic hydrocarbons

A novel, uniform nanosheet coating was hydrothermally grown in situ on pretreated NiTi alloy wire in an aqueous NaOH solution. The nanosheets were covalently linked to the NiTi substrate and crosslinked. They were radially oriented around the NiTi wire and composed of more titanium oxide than nickel oxide (TiO2/NiO). The TiO2/NiO composite nanosheet (TiO2/NiOCNSs) coating exhibited a porous structure, providing a desirable nanostructured support for subsequent uniform electrodeposition of AuNPs, which greatly improved the available surface area. The extraction performance of the AuNPs modified TiO2/NiOCNSs coated NiTi fiber was evaluated using aromatic compounds as model analytes and was coupled to HPLC with UV detection. The results obtained indicated that the novel fiber exhibited excellent extraction efficiency and good selectivity for polycyclic aromatic hydrocarbons (PAHs). The main experimental factors for PAHs extraction were optimized. Under the optimized conditions, good linearity was obtained in the range of 0.05–350 μg L−1 with correlation coefficients greater than 0.998. The limits of detection for the developed method ranged from 0.012 μg L−1 to 0.053 μg L−1. The single fiber repeatability and fiber-to-fiber reproducibility were less than 6.05% and 7.19%, respectively. The developed method was successfully applied to the selective concentration and sensitive determination of trace PAHs in different environmental water samples. Relative recoveries varied from 86.3% to 104% at spiking levels of 7 μg L−1 and 30 μg L−1 with relative standard deviations in the range of 4.4–7.5%. Furthermore, the novel fiber could be fabricated in a highly reproducible manner, and had a high stability and long life span.

Facile fabrication of polyaniline coated titania nanotube arrays as fiber coatings for solid phase microextraction coupled to high performance liquid chromatography for sensitive determination of UV filters in environmental water samples

A novel polyaniline coated titania composite nanotube (TiO2@PANI CNT) array was fabricated on a titanium wire by direct electrochemical oxidation. The effects of acid media, the concentration of aniline monomers and applied voltages on the electropolymerization of aniline were investigated. Surface morphological and compositional analyses revealed that a thin PANI coating was uniformly immobilized onto the TiO2 nanotube array. This TiO2@PANI CNT coating combined the merits of both PANI and TiO2, and thereby has several advantages over that of individual PANI and TiO2 coatings such as improved extraction efficiency for UV filters, enhanced mechanical stability and prolonged service life. Coupled with a high performance liquid chromatography-ultraviolet detector (HPLC-UV), the applicability of the developed fiber was evaluated through extraction of UV filters. The linear range is 0.25–500 μg L−1 with correlation coefficients of 0.9953 to 0.9998. The recoveries varied from 92.6% to 110% and the relative standard deviations for single fiber repeatability and fiber-to-fiber reproducibility were between 4.3% and 5.7% and between 6.9% and 9.3%, respectively. The limits of detection ranged from 0.04 to 0.06 μg L−1. The developed SPME-HPLC-UV method is suitable for sensitive determination of UV filters in environmental water samples.

Electrophoretic deposition hyphenated with electrochemical anodization for the fabrication of phenyl-functionalized mesoporous silica onto Nitinol fibers for selective solid-phase microextraction of polycyclic aromatic hydrocarbons

Electrophoretic deposition (EPD) was hyphenated with electrochemical anodization for the fabrication of phenyl modified mesoporous silica (MPS-Ph) particles onto Nitinol (NiTi) wire as a solid-phase microextraction (SPME) fiber. The anodized NiTi wire offers an ideal conductive fiber substrate with a large available contact surface for subsequent EPD and surface modification of MPS particles. The resulting NiTi-based fiber showed better extraction selectivity and efficiency for polycyclic aromatic hydrocarbons (PAHs) compared with commercial polydimethylsiloxane and polyacrylate fibers. Under optimized conditions for SPME of PAHs, the proposed method presented wide linear ranges from 0.02 to 500 μg L−1 with correlation coefficients higher than 0.999. The limits of detection ranged from 3.6 ng L−1 to 5.2 ng L−1. Relative standard deviations (RSDs) for single fiber repeatability varied from 4.3% to 5.4% for intra-day and inter-day measurements (n = 5), and RSDs for fiber-to-fiber reproducibility from 6.0% to 6.9% (n = 5). Moreover, the resulting fiber was stable for at least 200 extraction and desorption cycles in SPME and was fabricated in a precisely controllable manner. The proposed method was successfully applied to the selective preconcentration and sensitive determination of target PAHs in river water, rain water and wastewater samples with recoveries from 89.4% to 102%.

Selective solid-phase microextraction of ultraviolet filters in environmental water with oriented ZnO nanosheets coated nickel-titanium alloy fibers followed by high performance liquid chromatography with UV detection

Uniform and dense ZnO nanosheets (ZnONSs) as a solid-phase microextraction (SPME) fiber coating were fabricated on the surface of nickel and titanium oxide composite nanosheets (NiO/TiO2CNSs) which were in situ grown on the Nitinol (NiTi) wire in a hydrothermal procedure. The SEM micrographs illustrate that ZnONSs with the average thickness of 50 nm have been electrochemically grown on the NiTi fibers. The interconnected ZnONSs coating presents a porous nanostructure with large surface area. The as-fabricated fiber exhibits high extraction capability and excellent extraction selectivity for ultraviolet (UV) filters among the selected aromatic compounds. The main parameters affecting extraction performance were examined and optimized. Under the optimized conditions, the calibration curves were linear from 0.05 to 500 ng mL-1 with correlation coefficients above 0.999. The limits of detection (S/N = 3) ranged from 0.011 to 0.042 ng mL-1, while the limits of quanitification (S/N = 10) were in the range of 0.037-0.14 ng mL-1. Relative standard deviations (RSDs) for the single fiber repeatability were less than 7.4% (n = 5) and RSDs for the fiber-to-fiber reproducibility were below 8.2% (n = 5). The proposed method was successfully applied to the proconcentraction and determination of trace UV filters in real water samples. Moreover, the ZnONSs coating can be fabricated in highly reproducible manner with long durability.

An effective strategy for controlled fabrication and self-assembled modification of template-supported silica nanosheets on a superelastic nickel-titanium alloy fiber for highly efficient solid-phase microextraction

Silica nanosheets (SiO2NSs) were successfully fabricated on the superelastic nickel-titanium alloy (NiTi) wire as a novel fiber for solid-phase microextraction (SPME). Before sol-gel coating, the NiTi wire was hydrothermally treated in alkaline solution for the in situ growth of NiO/TiO2 nanosheets (NiO/TiO2NSs). The sol-gel coating of SiO2 on the surface of NiO/TiO2NSs template was investigated and a thin shell of SiO2 was found to cover NiO/TiO2NSs, which can enlarge the effective surface area of the SiO2 coating. This SiO2 capped NiO/TiO2NSs coated NiTi (NiTi@NiO/TiO2@SiO2NSs) fiber shows good extraction selectivity for polycyclic aromatic hydrocarbons (PAHs) and enhanced mechanical stability. After the self-assembled modification of SiO2NSs by phenyltrichlorosilane, the NiTi@NiO/TiO2@SiO2NSs@Ph fiber shows higher extraction capability for non-polar PAHs. Thus, the conditions for the extraction of PAHs were investigated and optimized coupled to HPLC with UV detection. Under the optimized conditions, the analytical parameters of the SPME-HPLC methods with the NiTi@NiO/TiO2@SiO2NSs and the NiTi@NiO/TiO2@SiO2NSs@Ph fibers were determined and compared. The SPME-HPLC method with the NiTi@NiO/TiO2@SiO2NSs@Ph fiber was developed for the concentration and the determination of PAHs in environment water samples. The relative recovery of PAHs in real water samples spiked at 5 μg L-1, 10 μg L-1 and 30 μg L-1 ranged from 88.1% to 109%. Furthermore, this fiber is stable due to the chemical bonding between different coatings and NiTi substrates. The fabrication of the NiO/TiO2@SiO2NSs@Ph coating on the NiTi fiber substrate is precisely controllable.