C12-Ag wire as solid-phase microextraction fiber for determination of benzophenone ultraviolet filters in river water

Biochar nanosphere-functionalized carbon fibers for in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental water followed by liquid chromatography and diode array detection

In order to improve the extraction ability of carbon fibers (CFs) for microextraction of polycyclic aromatic hydrocarbons (PAHs), biochar nanospheres derived from glucose were in-situ grown onto the surface of CFs via hydrothermal synthesis. The surface morphology and elemental composition of biochar nanospheres-CFs were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. Thereafter, the biochar nanosphere-CFs were pulled into the polyetheretherketone tube for solid-phase microextraction, and the tube was combined with high-performance liquid chromatography-diode array detector to online detect PAHs. With the help of π-stacking, hydrophobic, and hydrophilic effect of biochar nanospheres, the extraction efficiency of CFs was greatly enhanced (enrichment factor increased by 293% compared with  the original). The conditions affecting the analytical performance (sampling volume, sampling rate, methanol content, and desorption time) were investigated. Under the optimal conditions, an online analytical method for microextraction and determination of several PAHs was developed, and satisfactory results were achieved. The limits of detection were 0.003-0.010 ng mL-1 owing to high enrichment effect (2973-3600), linearity ranged from  0.010-15.0 ng mL-1, and relative standard deviations were 0.4%-1.6% (intra-day) and 2.4%-4.4% (inter-day), respectively. The method was applied to analyze environmental water samples (rain water, snow water, and river water), and spiked recoveries within 80.0%-119% were obtained.

Silica Aerogel Hybridized with Melamine-Terephthalaldehyde Polymer for In-Tube Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons from Environment Water

To improve the extraction performance of the silica aerogel, a melamine-terephthalaldehyde polymer was used to hybridize silica aerogel, and the hybridized aerogel was coated on the surface of stainless steel wire to prepare a fiber-filled extraction tube through placing four wires into a polyetheretherketone tube. The tube was combined with high-performance liquid chromatography, then the online extraction and detection were established. Several polycyclic aromatic hydrocarbons (PAHs) were selected as the target analytes. Under the optimum extraction and desorption conditions, the limit of detection was as low as 3.0 ng L⁻¹, and the linear range was 0.01–20.0 μg L⁻¹. The enrichment factors of PAHs were in the range of 1724–2393. Three environmental water samples of mineral water, tap water and river water were analyzed by this method, and the recoveries that spiked at 1.0–10.0 μg L⁻¹ were between 80.5–126%. It showed many advantages compared with other methods, such as better sensitivity, faster detection and online analysis.

Controllable in situ growth of novel octahedral TiO2 nanoparticles on nickel/titanium alloy fiber substrate for selective solid-phase microextraction of ultraviolet filters in water samples

The nature and fabrication of fiber coatings with good adsorption capacity and selectivity play a decisive role in solid-phase microextraction (SPME). In this work, a novel SPME fiber was fabricated through hydrothermal in situ growth of octahedral TiO₂ nanoparticles (TiO₂NPs) on a superelastic nickel/titanium alloy (NiTi) wire substrate in acid solution. The resulting fiber coatings were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Acid types, acid concentration as well as hydrothermal temperature and time were found to be effective route to manipulate the morphologies and composition of TiO₂-based nanoflakes grown on the NiTi fiber substrates. At the concentration of 0.4 mol L⁻¹ HCl as well as hydrothermal temperature of 150 °C and hydrothermal time of 12 h, TiO₂NPs were in situ grown on the NiTi wire substrates. The obtained NiTi wire with the TiO₂NPs coating (NiTi@TiO₂NPs fiber) was employed to investigate the adsorption of some representative aromatic analytes in water samples coupling with high-performance liquid chromatography with UV detection (HPLC/UV). The results clearly demonstrate that the fiber exhibits good extraction selectivity for ultraviolet filters (UVFs). In view of good extraction selectivity for the selected UVFs, the key experimental parameters were optimized. Under the optimum conditions, the calibration curves were linear in the ranges of 0.05–100 μg L⁻¹ with the correlation coefficients greater than 0.998. Limits of detection (LODs) were 0.007 to 0.064 μg L⁻¹. Furthermore, the intra-day and inter-day repeatability of the proposed method with the single fiber varied from 4.3% to 6.1% and from 4.5% to 6.8%, respectively. The fiber-to-fiber reproducibility ranged from 5.8% to 8.2%. The developed SPME-HPLC/UV method was applied to selective preconcentration and sensitive determination of target UVFs from real water samples. Moreover, the fabricated fiber showed precisely controllable growth and 150 extraction and desorption cycles.

This work presents a facile strategy with in situ growth of TiO₂ nanoparticles on nickel/titanium alloy wire through hydrothermal method for selective preconcentration and determination of UVFs in water.

Silver nanoparticles supported onto a stainless steel wire for direct-immersion solid-phase microextraction of polycyclic aromatic hydrocarbons prior to their determination by GC-FID

The authors describe a new coating for use in solid-phase microextraction (SPME). Silver nanoparticles (AgNPs) were prepared by using gallic acid or glucose as the reducing agents, and then supported onto a stainless steel wire that was previously coated with a silver mirror. Coating with AgNPs was performed by a layer-by-layer approach of up to eight cycles of consecutive deposition of AgNPs and the thiol linker 1,8-octanedithiol. This procedure allows proper control of the coating thickness. Thicknesses are 3.2 μm and 3.5 μm with AgNPs obtained with gallic acid and glucose, respectively. This is in agreement with theoretical estimations (3.8 μm). The fibers were used in the direct-immersion SPME-GC-FID determination of 16 polycyclic aromatic hydrocarbons (PAHs) from different waters. The performance of the method was compared to the one using polydimethylsiloxane fibers (100 μm), which is the most suitable commercial SPME fiber for PAHs. Despite the low thickness of the AgNP coatings (compared to PDMS), the analytical features of the method using the most adequate coating (AgNPs prepared with gallic acid) include: (a) limits of detection down to 0.6 ng·mL^-1; (b) intra-day, inter-day, and inter-fiber precisions (expressed as RSDs) lower than 22, 26 and 25%, respectively; and (c) an operational lifetime of ~150 extractions/desorption cycles. The analysis of various spiked environmental waters using these fibers resulted in adequate analytical performance. Graphical abstract Silver nanoparticle based coatings for solid-phase microextraction fibers were prepared by a layer-by-layer approach. They were used for determination of 16 PAHs in waters by gas chromatography. Limits of detection are < 14 μg·L^-1 and intra-day, inter-day, and inter-fiber precisions are <26%.

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%.

Advances in analytical methods and occurrence of organic UV-filters in the environment--A review

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more frequently and deeply.

In situ growth and phenyl functionalization of titania nanoparticles coating for solid-phase microextraction of ultraviolet filters in environmental water samples followed by high performance liquid chromatography-UV detection

Based on TiO2-nanoparticles coating fabricated by a one-step anodization method on titanium wire substrate, a novel phenyl functionalized solid-phase microextraction (SPME) fiber coating was prepared by simple and rapid in situ chemical assembling technique between the fiber surface titanol groups and trichlorophenylsilane reaction. The as-fabricated fiber exhibited good extraction capability for some UV filters and was employed to determine the ultraviolet (UV) filters in combination with high performance liquid chromatography-UV detection (HPLC-UV). The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the developed method was applied to detect several UV filters at trace concentration levels with only 8 mL of sample volume. They were determined in the range from 0.005 to 25 μg L(-1) with detection limits (S/N=3) from 0.1 to 50 ng L(-1). The relative standard deviations (RSDs) for single fiber repeatability varied from 4.6 to 6.5% (n=5) and fiber-to-fiber reproducibility (n=5) ranged from 5.5 to 9.1%. The linear ranges spanned two-four magnitudes with correlation coefficients above 0.9990. Five real water samples including four Yellow River water samples and one rain water sample were determined sensitively with good recoveries ranging from 86.2 to 105.5%. The functionalized fiber coating performed good reproducible manner, high mechanical strength, good stability and long service life. Moreover, this study proposed an efficient sample pretreatment method for the determination of UV filters from environmental water samples.

Fabrication and application of zinc-zinc oxide nanosheets coating on an etched stainless steel wire as a selective solid-phase microextraction fiber

A novel zinc-zinc oxide (Zn-ZnO) nanosheets coating was directly fabricated on an etched stainless steel wire substrate as solid-phase microextraction (SPME) fiber via previous electrodeposition of robust Zn coating. The scanning electron micrograph of the Zn-ZnO nanosheets coated fiber exhibits a flower-like nanostructure with high surface area. The SPME performance of as-fabricated fiber was investigated for the concentration and determination of polycyclic aromatic hydrocarbons, phthalates and ultraviolet (UV) filters coupled to high performance liquid chromatography with UV detection (HPLC-UV). It was found that the Zn-ZnO nanosheets coating exhibited high extraction capability, good selectivity and rapid mass transfer for some UV filters. The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the calibration graphs were linear over the range of 0.1-200μgL(-1). The limits of detection of the proposed method were 0.052-0.084μgL(-1) (S/N=3). The single fiber repeatability varied from 5.18% to 7.56% and the fiber-to-fiber reproducibility ranged from 6.74% to 8.83% for the extraction of spiked water with 50μgL(-1) UV filters (n=5). The established SPME-HPLC-UV method was successfully applied to the selective concentration and sensitive determination of target UV filters from real environmental water samples with recoveries from 85.8% to 105% at the spiking level of 10μgL(-1) and 30μgL(-1). The relative standard deviations were below 9.7%.

Self-assembly of alkyldithiols on a novel dendritic silver nanostructure electrodeposited on a stainless steel wire as a fiber coating for solid-phase microextraction

A facile and efficient electrodeposition approach for the controllable preparation of dendritic silver nanostructure was developed on an etched stainless steel (ESS) wire.

Au nanoparticle decorated graphene oxide as a novel coating for solid-phase microextraction

A novel solid-phase microextraction (SPME) fiber based on a stainless steel wire coated with Au nanoparticle decorated graphene oxide was prepared using a novel protocol.