Ru-Song Zhao

Metal–organic framework MIL-53(Al) as a solid-phase microextraction adsorbent for the determination of 16 polycyclic aromatic hydrocarbons in water samples by gas chromatography–tandem mass spectrometry

In this paper, the potential applications of metal-organic framework (MOF) materials as fiber coatings for the solid-phase microextraction (SPME) of polycyclic aromatic hydrocarbons (PAHs) in water samples were explored. Fibers coated with MIL-53(Al, Cr, Fe) materials were fabricated by an adhesive method for SPME. The quantitation was performed by gas chromatography-tandem mass spectrometry (GC-MS/MS) using the multiple reaction monitoring mode. Among the three MIL-53(M) coatings, MIL-53(Al) showed the highest extraction efficiency towards PAHs under the current fabrication procedure. Under optimized conditions, the MIL-53(Al)-coated fiber showed good precision (relative standard deviation <12.5%), low detection limits (0.10 ng L(-1) to 0.73 ng L(-1), S/N = 3), and good linearity (R(2) > 0.98) for aqueous solutions containing 16 PAH . The fiber also offered high thermal and chemical stability. The method developed based on MIL-53(Al) SPME-GC-MS/MS was successfully applied in the analysis of real water samples. Based on the simulation results, the PAHs were adsorbed on MIL-53(Al) primarily through the hydrophobic and π-π interactions between PAHs and the organic linker of the material. The results presented in this paper indicate that water-stable MOF materials have great potential for the SPME of aromatic compounds in water samples.

Fe3O4@MOF core–shell magnetic microspheres for magnetic solid-phase extraction of polychlorinated biphenyls from environmental water samples

Fe3O4@MIL-100 core-shell magnetic microspheres were, for the first time, used as the sorbent for the magnetic solid-phase extraction (MSPE) of polychlorinated biphenyls at trace levels in environmental water samples. GC coupled with tandem MS was used for sample quantification and detection. The Box-Behnken design was used to determine the optimum extraction parameters influencing extraction efficiency through response surface methodology. Under the optimized conditions, the developed method showed good linearity within the range of 5-4000ngL(-1), low limits of detection (1.07-1.57ngL(-1); signal-to-noise ratio=3:1), and good extraction repeatability (relative standard deviation<12%; n=5). Environmental samples collected from the Yellow River, local lake, wastewater, and snow water were processed using the developed method. The results demonstrated that the Fe3O4@MOF core-shell magnetic microspheres are promising sorbents in the MSPE of aromatic pollutants from environmental water samples.

Investigation of feasibility of bamboo charcoal as solid-phase extraction adsorbent for the enrichment and determination of four phthalate esters in environmental water samples.

This paper demonstrates, for the first time, that adsorptive potential of bamboo charcoal for solid-phase extraction of phthalate esters was investigated. The four phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP) and di-n-butyl phthalate (DBP), are quantitatively adsorbed on a bamboo charcoal packed cartridge, then the analytes retained on the cartridge are quantitatively desorbed with optimum amounts of acetone. Finally, the analytes in the eluant acetone are determined by high-performance liquid chromatography-ultraviolet detectior. Important parameters influencing the extraction efficiency, such as eluant and its volume, flow rate of sample, sample volume, pH, the amount of adsorbent and ionic strength were investigated and optimized in detail. Under the optimum conditions, the limits of detection were 0.35-0.43 microg/L for four phthalate esters. The proposed method has been applied to the analysis of rainwater and tap water samples. And satisfactory spiked recoveries were obtained in the range of 75.0-114.2%. All the results indicated that the bamboo charcoal has great potential as a novel adsorbent material for the enrichment and determination of phthalate esters in real environmental water samples.

In situ hydrothermal growth of ytterbium-based metal–organic framework on stainless steel wire for solid-phase microextraction of polycyclic aromatic hydrocarbons from environmental samples

In this paper, we report the use of a porous ytterbium-based metal-organic framework (Yb-MOF) coating material with good thermal stability for the headspace solid-phase microextraction (HS-SPME) of polycyclic aromatic hydrocarbons (PAHs) from environmental samples. The Yb-MOF thin films, grown in situ on stainless steel wire in solution, exhibited high selectivity and sensitivity toward PAHs. Under the optimal conditions, the novel fibers achieved large enrichment factors (130-2288), low limits of detection (0.07-1.67ngL(-1)), and wide range of linearity (10-1000ngL(-1)) for 16 PAHs in the tested samples. The novel fiber was successfully used in the analysis of PAHs in real environmental samples. These results demonstrated that Yb-MOF is a promising coating material for the SPME of PAHs at trace levels from environmental samples.

Feasibility of metal-organic nanotubes [Cu3(μ3-O)(μ-OH)(triazolate)2]+-coated fibers for solid-phase microextraction of polychlorinated biphenyls in water samples.

Metal-organic nanotubes (MONTs), a novel class of hybrid materials, have attracted considerable attention because of their uniform and fixed internal diameters, impressive topological structures, and versatile applications. However, to the best of our knowledge, no studies on MONTs coating fabrication for solid-phase microextraction are yet available. The aim of this work is to investigate the feasibility of using [Cu3(μ3-O)(μ-OH)(triazolate)2]+ as a solid-phase microextraction coating material to enrich trace levels of polychlorinated biphenyls in water samples. The novel [Cu3(μ3-O)(μ-OH)(triazolate)2]+-coated fibers achieved large enhancement factors (396–1343), low limits of detection (3.9–21.7 pg L−1), and wide linearity (0.1–500 ng L−1) for detecting polychlorinated biphenyls. Relative standard deviations obtained ranged from 2.12 to 7.22%, and spiked PCBs recoveries (spiking concentrations of 1 and 5 ng L−1) in four environmental water samples ranged from 71.3 to 104%. These findings indicate that [Cu3(μ3-O)(μ-OH)(triazolate)2]+ as a solid-phase microextraction coating material is an excellent alternative for the rapid and sensitive analysis of trace levels of polychlorinated biphenyls in the environment.

Carboxylated solid carbon spheres as a novel solid-phase microextraction coating for sensitive determination of phenols in environmental water samples

The high performance separation and enrichment of polar phenols from aqueous matrices is often difficult due to the strong interactions between phenols and water. In this paper, carboxylated solid carbon spheres (SCSs-COOH) were, for the first time, used as a novel coating material in the solid-phase microextraction (SPME) of polar phenols at ultra-trace levels in environmental water samples. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was applied for sample quantification and detection. The novel SCSs-COOH-coated fiber exhibited good thermal stability (>330 °C) and higher extraction efficiency than commercial fibers in the extraction of phenols. The Plackett-Burman design was employed to optimize the extraction factors affecting the extraction efficiency through a response surface methodology. A possible phenol extraction mechanism enabled by the SCSs-COOH-coated fiber is proposed. Under the optimized conditions, low detection limits (0.26-2.63 ng L(-1)), a wide linear range (1-1000 ng L(-1)), good repeatability (2.00-9.02%, n=5) and excellent reproducibility (2.08-8.55%, n=3) were achieved. The developed method was validated against several environmental water samples, with satisfactory results being obtained each case.

Using bamboo charcoal as solid-phase extraction adsorbent for the ultratrace-level determination of perfluorooctanoic acid in water samples by high-performance liquid chromatography-mass spectrometry

In recent years, bamboo charcoal, a new kind of material with special microporous and biological characteristics, has attracted great attention in many application fields. In this paper, the potential of bamboo charcoal to act as a solid-phase extraction (SPE) adsorbent for the enrichment of the environmental pollutant perfluorooctanoic acid, which is one of the newest types of persistent organic pollutants in the environment, has been investigated. Important factors that may influence the enrichment efficiency—such as the eluent and its volume, the flow rate of the sample, the pH of the sample and the sample volume—were investigated and optimized in detail. Under the optimum conditions, the limit of detection for PFOA was 0.2xa0ng L−1. The experimental results indicated that this approach gives good linearity (R2u2009=u20090.9995) over the range 1–1000xa0ng L−1 and good reproducibility, with a relative standard deviation of 4.0% (nu2009=u20095). The proposed method has been applied to the analysis of real water samples, and satisfactory results were obtained. The average spiked recoveries were in the range 79.5∼118.3 %. All of the results indicate that the proposed method could be used for the determination of PFOA at ultratrace levels in water samples.

Carbon nanotube composite microspheres as a highly efficient solid-phase microextraction coating for sensitive determination of phthalate acid esters in water samples

Multiwalled carbon nanotubes (MWCNTs) on polystyrene (PS) microspheres have been designed and prepared by layer-by-layer assembly via electrostatic interaction. MWCNTs@PS was characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The new materials were employed as a novel solid-phase microextraction (SPME) coating to enrich trace level of phthalate acid esters (PAEs) in water samples. Five PAEs, di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl adipate (DEHA), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP), were studied in this work. The Box-Behnken design was applied to calculate optimum extraction factors affecting the extraction efficiency using a response surface. In the optimized conditions, the developed technique achieved high enrichment factors (738-2347), low limits of detection (0.0012-0.018μgL-1) and wide linearity (0.001-5μgL-1) for detecting PAEs. The method was successfully applied to analyze PAEs in real environmental water samples with recovery ranging from 73.4% to 103.8%. The results demonstrated that MWCNTs@PS are a promising coating material in the SPME of PAEs at trace levels from environmental samples.

A cadmium(II)-based metal-organic framework material for the dispersive solid-phase extraction of polybrominated diphenyl ethers in environmental water samples.

In this study, a stable cadmium(II)-based metal-organic framework (MOF) material was designed and used as a sorbent for the dispersive solid-phase extraction (dSPE) of polybrominated diphenyl ethers (PBDEs) in environmental water samples. Gas chromatography coupled with triple quadrupole mass spectrometer (GC-MS/MS), working in the negative chemical ionization mode, was used to quantify the target analytes. Characterization of the material was performed by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), elementary analyses (EA) and thermogravimetric analyses (TGA). The synthesized rod shape MOF is on the micro level in size and has excellent chemical and solvent stability. The extraction conditions, including the extraction time, temperature and ionic strength, were examined systematically using response surface methodology (RSM). Under optimized conditions, the method that was developed showed an excellent extraction performance. Good linearity (R(2)>0.99) within the concentration range of 0.25-250ngL(-1) was obtained. Low limits of detection (0.08-0.15ngL(-1), signal-to-noise ratio=3:1) and good precision (relative standard deviation <12%, n=6) were achieved. The developed method was applied to analyze natural and spiked environmental water samples.

Ultrathin-shell boron nitride hollow spheres as sorbent for dispersive solid-phase extraction of polychlorinated biphenyls from environmental water samples.

Boron nitride hollow spheres with ultrathin-shells were synthesized and used as sorbents for dispersive solid-phase extraction of aromatic pollutants at trace levels from environmental water samples. Polychlorinated biphenyls (PCBs) were selected as target compounds. Sample quantification and detection were performed by gas chromatography-tandem mass spectrometry. Extraction parameters influencing the extraction efficiency were optimized through response surface methodology using the Box-Behnken design. The proposed method achieved good linearity within the concentration range of 0.15-250 ng L(-1) PCBs, low limits of detection (0.04-0.09 ng L(-1), S/N=3:1), good repeatability of the extractions (relative standard deviation, <12%, n=6), and satisfactory recoveries between 84.9% and 101.0% under optimal conditions. Real environmental samples collected from rivers, local lakes, rain and spring waters were analyzed using the developed method. Results demonstrated that the hexagonal boron nitride-based material has significant potential as a sorbent for organic pollutant extraction from environmental water samples.