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

The environmental sources of benzophenones: Distribution, pretreatment, analysis and removal techniques

Benzophenones (BPs) have wide practical applications in real human life due to its presence in personal care products, UV-filters, drugs, food packaging bags, etc. It enters the wastewater by daily routine activities such as showering, impacting the whole aquatic system, then posing a threat to human health. Due to this fact, the monitoring and removal of BPs in the environment is quite important. In the past decade, various novel analytical and removal techniques have been developed for the determination of BPs in environmental samples including wastewater, municipal landfill leachate, sewage sludge, and aquatic plants. This review provides a critical summary and comparison of the available cutting-edge pretreatment, determination and removal techniques of BPs in environment. It also focuses on novel materials and techniques in keeping with the concept of "green chemistry", and describes on challenges associated with the analysis of BPs, removal technologies, suggesting future development strategies.

Determination of Phthalate Esters in Cosmetics and Baby Care Products by a Biosorbent Based on Lawsone Capped Chitosan and Followed by Liquid Chromatography

This research presents a green synthetic pathway for the preparation of a new biosorbent and eco-friendly extraction process of three phthalate esters: dimethyl phthalate, di-butyl phthalate and benzyl butyl phthalate, from cosmetics and baby care products. Dispersive solid-phase extraction was used based on a new core-shell biomass/sorbent; chitosan-loaded lawsone. The proposed method provides fortunate trapping of phthalate esters in a one-step extraction. Under the optimized extraction conditions, the current work was presented low detection limits (0.03-0.15 ng. g-1), limits of quantification (0.1-0.5 ng·g-1) and reasonable linearity (0.1-10 000 ng. g-1). The applicability of the method was estimated by recovery experiments at different spiking levels (n = 5) for phthalate esters in the real samples.

Comparison of automated mixer-assisted mini-scale liquid-liquid extraction coupled with full evaporation dynamic headspace extraction with United States Environmental Protection Agency methods for the gas chromatography-mass spectrometric analysis of chlorinated benzenes

Three modes of facilitating mini-scale-liquid-liquid-extraction (msLLE) prior to automated integration with full evaporation dynamic headspace (FEDHS) extraction were evaluated in this work. For msLLE, 1.2 mL of dichloromethane (DCM) was added to a conical-bottomed vial containing 7 mL of aqueous sample. The solution was then subjected to three different mixing modes, namely vortex-assistance (where a "whirlpool" was created in the solution), agitation-assistance (where the vial was rotated in circular motion) and ^quickMix-assistance (where the vial was shaken at a high speed). Vortex-assistance was performed manually while the other two modes were automated using a commercial autosampler. Following this, the DCM extract was transferred automatically to another vial and was then vaporized and sent through a Tenax TA sorbent tube in the FEDHS step. Due to the stronger π interaction between the sorbent and the analytes of interest, the analytes were selectively concentrated while the DCM vapor passed through unhampered. After FEDHS, the analytes were thoroughly desorbed into a gas chromatography-mass spectrometric system for analysis. The applicability of this procedure was validated in the extraction of six chlorinated benzenes (CBs) (1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzne and hexachlorobenzene) from aqueous samples. The ^quickMix-assisted msLLE-FEDHS approach achieved good absolute extraction recoveries (between 74.2% and 88.7%), low limits of detection (between 0.0006 and 0.0116 µg/L), good linearity (r²≥0.9920), good repeatability (between 1.9% and 8.4%, and good reproducibility (between 9.0% and 13.6%). It was found to be superior to the methods published by the United States Environmental Protection Agency. Five consecutive fully automated ^quickMix-assisted-msLLE-FEDHS-GC-MS runs spanned only ca. 4 hr.

Selective and efficient solid-phase microextraction of polycyclic aromatic hydrocarbons in water by robust two-dimensional zinc oxide nanosheets grown on a superelastic nickel-titanium alloy fiber prior to determination by HPLC-UV

Oriented zinc oxide nanosheets (ZnONSs) were directly grown on pretreated nickel-titanium alloy (NiTi) fiber substrates without a traditional seeding layer of ZnO by electrochemical deposition for the first time. The fiber coatings were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. Direct growth of ZnONSs on the NiTi fiber substrate was dependent on the type of zinc salt. The adsorption performance of the ZnONSs coatings was evaluated using representative aromatic compounds as model analytes together with high performance liquid chromatography with ultraviolet detection. The as-prepared fiber shows higher extraction capability for the selected polycyclic aromatic hydrocarbons (PAHs) than for ultraviolet filters in water samples, and better extraction selectivity for PAHs. For this purpose, the important experimental parameters were optimized for the extraction of PAHs. Under the optimized conditions, the calibration curves are linear in the range of 0.03-200 μg L-1 with correlation coefficients greater than 0.999. Limits of detection ranged from 0.011 μg L-1 to 0.082 μg L-1. Intra-day and inter-day relative standard deviations (RSDs) of the developed method with a single fiber ranged from 2.69% to 4.18% and from 4.44% to 5.40%, respectively. RSDs for the fiber-to-fiber reproducibility varied between 5.57% and 7.66%. The developed method was successfully applied for selective preconcentration and determination of trace PAHs in five real water samples. Relative recoveries varied from 84.5% to 104% with RSDs between 1.65% and 8.30%. Furthermore, the as-prepared fiber is highly stable.

Recent Applications and Newly Developed Strategies of Solid-Phase Microextraction in Contaminant Analysis: Through the Environment to Humans

The present review aims to describe the recent and most impactful applications in pollutant analysis using solid-phase microextraction (SPME) technology in environmental, food, and bio-clinical analysis. The covered papers were published in the last 5 years (2014–2019) thus providing the reader with information about the current state-of-the-art and the future potential directions of the research in pollutant monitoring using SPME. To this end, we revised the studies focused on the investigation of persistent organic pollutants (POPs), pesticides, and emerging pollutants (EPs) including personal care products (PPCPs), in different environmental, food, and bio-clinical matrices. We especially emphasized the role that SPME is having in contaminant surveys following the path that goes from the environment to humans passing through the food web. Besides, this review covers the last technological developments encompassing the use of novel extraction coatings (e.g., metal-organic frameworks, covalent organic frameworks, PDMS-overcoated fiber), geometries (e.g., Arrow-SPME, multiple monolithic fiber-SPME), approaches (e.g., vacuum and cold fiber SPME), and on-site devices. The applications of SPME hyphenated with ambient mass spectrometry have also been described.

Double -shelled hollow ZnO/carbon nanocubes as an efficient solid-phase microextraction coating for the extraction of broad-spectrum pollutants

Efficient extraction of pollutants with different chemical properties from environmental samples has attracted great attention in the development of analytical chemistry. However, it is still a challenge to develop an appropriate and sensitive adsorbent for determining broad-spectrum analytes. Herein, zeolitic imidazole framework-8 (ZIF-8)-derived double-shelled hollow zinc oxide/carbon (ZnO/C) nanocubes were reported as a novel coating for solid-phase microextraction (SPME). The nanocubes with a unique structure and composition were obtained by controlled etching of ZIF-8 with tannic acid (TA) followed by pyrolysis. When a ZnO/C nanocube-coated fiber (ZnO/C-F) was used to extract the complex environmental samples containing both nonpolar (benzene compounds (BTEX)) and polar (chlorophenols (CPs)) pollutants, excellent extraction performance was achieved; we obtained low detection limits (0.14-0.56 ng L-1 for BTEX and 1.10-2.84 ng L-1 for CPs), good repeatability (2.2-5.9% for six replicated extractions) and excellent reproducibility (0.61-7.8%, fiber to fiber). The broad-spectrum SPME performance was ascribed to the synergistic effect between the composition and structure of ZnO/C nanocubes. Compositionally, the uniform dispersion of ZnO and carbon framework could provide abundant adsorption active sites, where Zn-OHs bound CPs by hydrogen bonding and carbon absorbed BTEX through π-π stacking interaction and hydrophobic interaction. Structurally, the double-shelled hollow morphology of the nanocubes was favorable for the sensitive extraction. Finally, the established ZnO/C-F-based headspace-SPME method was used for the preconcentration and determination of abundant analytes from real water samples. These findings open the door for the practical use of double-shelled hollow multicompositional inorganic materials.

Oriented ZnO nanoflakes on nickel-titanium alloy fibers for solid-phase microextraction of polychlorinated biphenyls and polycyclic aromatic hydrocarbons

ZnO nanoflakes (ZnONFs) were electrochemically grown on a nickel-titanium alloy (NiTi) wire for use in solid-phase microextraction. Prior to the growth of ZnONFs, the NiTi wire was hydrothermally treated for in-situ growth of TiO₂/NiO nanoflakes as a seeding base. The applied potential was used to control the dimensions of vertically oriented hexagonal ZnONFs. After annealing at 600 °C, the resulting fiber display fairly selective affinity for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons. The fibers were applied to the preconcentration of PCBs which then were quantified by HPLC with UV detection. Compared to commercial polydimethylsiloxane coatings, the new coating displays high extraction capability, rapid extraction kinetics and superior cycling stability. This is assumed to be due to its high surface-to-volume ratio, double-sided open access structure, and enhanced structural stability. The assay excels by (a) a wide analytical range (0.10 to 200 μg L^-1 of PCBs), (b) low limits of detection (20-17 ng L^-1), and (c) low standard deviations for the single fiber repeatability (<9.8%) and for the fiber-to-fiber reproducibility (<7.5%). Satisfactory accuracy and precision were achieved when PCBs were determined by this method in spiked rain water, river water and wastewater samples. Graphical abstract ZnO nanoflakes were fabricated on a superelastic nickel-titanium alloy wire in desired orientation with enhanced extraction capability and good extraction selectivity. The fabricated fiber was suitable for the determination of PCBs in environmental water samples.

Simultaneous in-vial acetylation solid-phase microextraction followed by gas chromatography tandem mass spectrometry for the analysis of multiclass organic UV filters in water

UV filters are a class of emerging contaminants that are widely used in personal care products (PCPs) and that can be detected at low concentrations in the aquatic environment (ngL^-1). Sensitive modern analytical methods are then mandatory to accurately analyze them. A methodology based on solid-phase-microextraction (SPME), considered as a 'Green Chemistry' technique, followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) has been developed for the simultaneous analysis of 14 UV filters of different chemical nature in environmental and recreational waters. In-vial low-cost derivatization was carried out to improve chromatographic performance of phenolic compounds. The extraction parameters (fiber coating, extraction mode, and salt addition) were optimized by means of experimental designs in order to achieve reliable conditions. Finally, the SPME-GC-MS/MS method was validated in terms of linearity, accuracy and precision with LODs in the low ngL^-1 level. Its application to the analysis of 28 different samples including sea, river, spa, swimming pool, and aquapark waters, enabled the detection of 11 target UV filters at concentration levels up to 540μgL^-1, highlighting the presence of OCR in all analyzed samples and of 2EHMC (proposed to be considered as priority pollutant) in 79% of them.

Phenyl carbamate functionalized zinc oxide nanorods for paper-based thin film microextraction

In this work, phenyl carbamate functionalized zinc oxide nanorods were fabricated on a cellulose filter paper and employed as a novel and low cost sorbent in a thin film microextraction (TFME) technique.

Nanostructured metal–organic frameworks, TMU-4, TMU-5, and TMU-6, as novel adsorbents for solid phase microextraction of polycyclic aromatic hydrocarbons

Zn(ii) based metal–organic frameworks were coated onto stainless steel wire and applied to the headspace solid phase microextraction of PAHs.

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%.

In situ solvothermal synthesis of metal-organic framework coated fiber for highly sensitive solid-phase microextraction of polycyclic aromatic hydrocarbons

The present work reported a facile and simple in situ solvothermal growth method for immobilization of metal-organic framework UiO-66 via covalent bonding on amino functional silica fiber for highly sensitive solid-phase microextraction (SPME) of ten polycyclic aromatic hydrocarbons (PAHs) by coupling with gas chromatography-mass spectrometry (GC-MS) analysis. The developed SPME coated fiber has been characterized through SEM, TGA and XRD, confirmed the coating thickness of ∼25μm with high thermal and chemical stability. Under optimized conditions, the obtained method exhibited satisfactory linearity in range of 1.0-5000.0ngL(-1) for all the PAHs. The low detection limits were from 0.28ngL(-1) to 0.60ngL(-1) (S/N=3). The UiO-66 coated fibers showed good repeatability (RSDs less than 8.2%, n=5) and satisfying reproducibility between fiber to fiber (RSDs less than 8.9%, n=5). This method was successfully used for simultaneous determination of ten PAHs from Minjiang water and soil samples with satisfactory recoveries of 87.0-113.6% and 83.8-116.7%, respectively. Experimental results shows that the chemical bonding approach has dramatically improve the stability and lifetime of pure MOFs coating for SPME in sample pretreatment.