Highly Permeable Monolith-based Multichannel In-Tip Microextraction Apparatus for Simultaneous Field Sample Preparation of Pesticides and Heavy Metal Ions in Environmental Waters

Surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes for pipette tip solid-phase extraction of microcystins in water

The occurrence of microcystins (MCs) during harmful algal blooms (HABs) represents a major threat to freshwater environments. In this work, a novel surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes (PCSs) was prepared for the enrichment of MCs. The copolymerization of bifunctional amphiphilic monomers, 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-benzylquininium chloride (BQN), with the cross-linker methacryl substituted polyhedral oligomeric silsesquioxane (POSS) was achieved in an ionic liquid-based porogenic medium. The hierarchical porous structure, a variety of surface functional groups and weak hydrophilicity were well characterized on the prepared materials using scanning electron microscopy, nitrogen adsorption/desorption analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential analysis and water contact angle testing, respectively. The as-prepared surface amphiphilic PCSs was used as an adsorbent for pipette tip solid-phase extraction (PT-SPE) to enrich microcystins (MCs) from surface waters before their analysis by capillary electrochromatography (CEC) and liquid chromatography-mass spectrometry (LC-MS). Under the optimal conditions, the established PT-SPE-LC-MS method exhibited a wide linear range (10-10,000 ng L-1), low limits of detection (4.0-8.0 ng L-1) and satisfactory recoveries (89.5-102.8 %) for MCs. An adsorption mechanism involving electrostatic interactions, hydrogen bonding, hydrophilic interactions, and π-π stacking has been proposed. The findings suggest that the use of surface amphiphilic PCSs materials as adsorbents in the PT-SPE platform facilitates efficient enrichment of MCs for subsequent chromatographic analysis. These investigations offer a new perspective on the simple and uncomplicated pretreatment of complex environmental samples.

On-site extraction of phenoxycarboxylic acid herbicides in environmental waters utilizing monolith-based in-tip microextraction technique

On-site extraction plays a significant role in the reliable quantification of strong polar phenoxycarboxylic acid herbicides (PCAs) in aqueous samples. In current study, a new technique for the field sample preparation of PCAs was developed by means of three channels in-tip microextraction device (TCIM). To capture PCAs effectively, an extraction phase based on monolith (EPM) using vinylimidazole and divinylbenzene/ethylene dimethacrylate as monomer and cross-linkers, respectively, was in-situ synthesized in pipette tips. The EPM fabricated at optimal conditions were characterized by a series of techniques and employed as the adsorbent of TCIM for the on-site extraction of PCAs. The adsorption isotherm was studied so as to inspect the extraction behaviors of EPM towards PCAs. Results revealed that the proposed EPM/TCIM presented satisfactory extraction performance towards PCAs through multiple interactions. The enrichment factors and adsorption capacity were 74-277 and 20 mg g-1, respectively. Under the most beneficial extraction parameters, the developed EPM/TCIM was successfully employed to on-site extract PCAs, and then combining with HPLC equipped with diode array detector to monitor trace PCAs in actual waters. The limits of detection (LODs) towards investigated PCAs varied from 0.071 μg/L to 0.30 μg/L. In addition, the accuracy of established approach was inspected with documented method. Compared with existing lab-based sample preparation approaches, the introduced field sample preparation technique exhibits some merits such as avoidance of transporting large volume of water, prevention of analytes loss during sampling procedure, less usage of organic solvent and achievement of satisfactory efficient in sample preparation.

Field specific capture of Pb(II) in aqueous samples with three channels in-tip microextraction apparatus based on ion-imprinted polymer

On-site specific capture is a critical step in accurate analysis of trace Pb(II) in environmental waters. In this connection, a new Pb(II)-imprinted polymer-based adsorbent (LIPA) was in-situ prepared in pipette tip and used as the extraction medium of laboratory-made portable three channels in-tip microextraction apparatus (TIMA). Density function theory was employed to verify the selection of functional monomers for the preparation of LIPA. The physical and chemical properties of the prepared LIPA were inspected with various characterization techniques. Under the beneficial preparation parameters, the LIPA presented satisfactory specific recognition performance towards Pb(II). Selectivity coefficients of LIPA towards Pb(II)/Cu(II) and Pb(II)/Cd(II) were 6.82 and 3.27 times higher than that of non-imprinted polymer-based adsorbent, respectively, and the adsorption capacity towards Pb(II) was as high as 36.8 mg/g. Freundlich isotherm model fitted well with the adsorption data, revealing that the adsorption of Pb(II) on LIPA was a multilayer process. After optimizing the extraction conditions, the developed LIPA/TIMA was employed to field selectively separate and enrich trace Pb(II) in various environmental waters followed by quantification with atomic absorption spectrometry. The enhancement factor, linear range, limit of detection and RSDs for precision were 183, 0.50-10000 ng/L, 0.14 ng/L and 3.2-8.4%, respectively. Accuracy of the developed approach was inspected by means of spiked recovery and confirmation experiments. Achieved results reveal that the developed LIPA/TIMA technique is good for field selective separation and preconcentration of Pb(II) and the introduced approach can be used to measure ultra-trace Pb(II) in a variety of waters.

Electrospun composite nanofibers modified with silver nanoparticles for extraction of trace heavy metals from water and rice samples: An highly efficient and reproducible sorbent

Herein, a composite of polyacrylonitrile (PAN)/agar/silver nanoparticles (AgNPs) electrospun nanofibers was fabricated and applied as an efficient sorbent for thin-film micro-extraction (TFME) of five metal ions followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Incorporating agar into the nanofibers followed by in situ photo-reductive reaction under UV-lamp resulted in highly uniform dispersion of AgNPs in the nanofibers. Under the optimized conditions, agreeable linearity was acquired in the range of 0.5-250.0 ng mL^-1 (R² ≥ 0.9985). The LODs (based on S/N = 3) were attained in the range of 0.2 to 0.5 ng mL^-1. The relative standard deviations (RSDs) were between 4.5% and 5.6% (intra-day, n = 5) and 5.3%-5.9% (inter-day, n = 3) for three sequential days. The developed method was investigated with water and rice samples, and recoveries (93.9-98.0%) indicated that the PAN/agar/AgNPs could be a promising film for the adsorption of heavy metal ions in varied samples.

Molecularly imprinted monolith-based portable in-tip microextraction device for field specific extraction of triazine herbicides in aqueous samples followed by chromatographic quantification

Field selective extraction is crucial for accurate monitoring of triazine herbicides (TAHs) in aqueous samples. For this purpose, using atrazine as template and 3-acrylamido phenylboronic acid as functional monomer which was quickly screened with calculation simulation technology, a new molecularly imprinted monolith-based adsorbent (MBA) was fabricated and utilized as the extraction phase of laboratory-made multichannel in-tip microextraction device (MIMD). A series of techniques were adopted to characterize the physical and chemical properties of the synthesized MBA. Under the optimized preparation conditions, the recognition factor and capture capacity of MBA towards atrazine were as high as 2.9 and 23.4 mg/g, respectively, and the enrichment factors towards TAHs located in the range of 276-359. The study about adsorption isotherm evidenced the adsorption of MBA towards atrazine was fit for Freundlich adsorption model. Under the beneficial extraction parameters, the introduced MBA/MIMD was utilized to on-site extract TAHs in a variety of aqueous samples prior to HPLC determination. High sensitivity (limit of detection: 0.25-0.64 ng/L), good precision (relative standard deviation: 1.4-9.5%) and satisfying recovery (81.0-113%) were achieved. Accuracy and reliability of the introduced method were inspected through confirmation experiments. Owing to the good results and outstanding merits, the established MBA/MIMD technique is appropriate for field sample preparation of TAHs and the developed method can be utilized to monitor TAHs residuals in various aqueous samples.

Sponge-nested polymer monolith sorptive extraction

Polymer monoliths are an alternative to traditional particle-packed supports used in solid-phase extraction because of their ease of preparation, high porosity, and pH stability. They often required the attachment of monoliths to a support, such as the internal walls of a column to enable their use for sample preparation. Applications of free-standing polymer monoliths are rarely found because of their limited mechanical stability. Herein, divinylbenzene monoliths were polymerised within a commercial melamine-formaldehyde sponge using different polymerisation times. The sponge-nested polymer monoliths are highly robust, and their size and shape can be easily adjusted for desired applications. The prepared sponge-nested polymer monoliths had surface areas in the range of 237 m² g^-1 to 369 m² g^-1. A melamine-formaldehyde sponge cut into 1 cm³ cubes were used to template the polymer monoliths. Miniaturized monoliths with a size of 0.125 cm³ were directly cut from the larger cubes without compromising the integrity of the porous monolith structure. The resulting nested monolith sorptive extraction (NMSE) supports were applied for the extraction of the endocrine disruptors bisphenol A, 4-tert-butylphenol, and 4-tert-octylphenol. The prepared sponge-nested monoliths are low-cost (40 monoliths/AU$). NMSE was carried out by the direct immersion of the monoliths in the aqueous standards/samples, requiring only an orbital shaker for the extraction procedure. Best performance was obtained for polymer monoliths polymerized for 6 h, enabling limits of detection of 5.6 to 6.5 µg L^-1 for the selected analysis using HPLC-UV.

A New Trend and Future Perspectives of the Miniaturization of Conventional Extraction Methods for Elemental Analysis in Different Real Samples: A Review

Sample preparation is one of the viable procedures to be used before analysis to enhance sensitivity and reduce the matrix effect. The current review is mainly emphasized the latest outcome and applications of microextraction techniques based on the miniaturization of the classical conventional methods based on liquid-phase and solid-phase extraction for the quantitative elemental analysis in different real samples. The limitation of the conventional sample preparation methods (liquid and solid phase extraction) has been overcome by developing a new way of reducing size as compared with the conventional system through the miniaturization approach. Miniaturization of the sample preparation techniques has received extensive attention due to its extraction at microlevels, speedy, economical, eco-friendly, and high extraction capability. The growing demand for speedy, economically feasible, and environmentally sound analytical approaches is the main intention to upgrade the conventional procedures apply for sample preparation in environmental investigation. A growing trend of research has been perceived to quantify the trace for elemental analysis in different natures of real samples. This review also recapitulates the current futuristic scenarios for the green and economically viable procedure with special overemphasis and concentrates on eco-friendly miniaturized sample-preparation techniques such as liquid-phase microextraction (LPME) and solid-phase microextraction (SPME). This review also emphasizes the latest progress and applications of the LPME and SPME approach and their future perspective.

Preparation of monolith-based adsorbent containing abundant functional groups for field entrapment of nitrogen and sulfur containing aromatic compounds in environmental aqueous samples with portable multichannel in-tip microextraction device

Field sample preparation is important and interesting for analysis of nitrogen and sulfur containing aromatic compounds (N,S-CACs) in environmental aqueous samples. In this connection, a new functional groups-rich adsorbent based on porous monolith (ABM) was fabricated by in-situ copolymerization of allylaminocarbonylphenyl boronic acid/styrene and ethylene glycol dimethacrylate. The prepared ABM was employed as the extraction medium of homemade portable multichannel in-tip microextraction device (PMMD) for on-site entrapment of N,S-CACs in various waters. Because of the abundant functional groups, the obtained ABM/PMMD exhibited satisfactory capture capability towards studied N,S-CACs, and the enrichment factors varied from 454 to 491. Under the optimized fabrication conditions, adsorption and desorption parameters, the developed ABM/PMMD was used to field capture investigated N,S-CACs and followed by quantification with high performance liquid chromatography. The limits of detection were in the ranges of 0.00030-0.0016 µg/L. Recoveries with low, medium and high spiked contents located in the range of 82.1-118% with good repeatability (RSDs<9%). In addition, traditional laboratory sample pretreatment approach was employed to verify the reliability of the established method. Results well evidenced that the practicability of introduced ABM/PMMD in the field sample preparation of N,S-CACs in environmental waters.

High-throughput subzero-temperature assisted homogenous liquid-liquid extraction for the fast sample preparation of multiple phenolic compounds in propolis

In the present study, a high-throughput homogenous liquid-liquid extraction method was developed for fast sample preparation of multiple phenolic compounds in propolis. This method was proposed based on cooling samples array in subzero temperature to induce phase separation of ACN-H₂O extractant. Due to the high-throughput ability, optimization of extraction parameters was rapidly achieved by using a 5 × 4 × 3 samples array. In addition, multiple arrays were investigated for evaluating the analytical performance of the high-throughput method, which indicated that limits of detection and quantification were ranged from 0.04 to 0.35 µg/mL and 0.12 to 1.05 µg/mL, respectively. Recoveries and precisions in inter-day high-throughput studies were in the range of 90.55-105.50% and 2.58-4.30%, respectively. Comparing with the conventional liquid extraction method, this ecofriendly high-throughput method presented remarkable advantages in reducing sample and chemical consumption, as well as saving labor and time cost. The proposed method might provide a valuable strategy for the design of high-throughput extraction procedures.

Recent advances in micro- and nanomaterial-based adsorbents for pipette-tip solid-phase extraction

There are a lot of review papers of sample pretreatment, but the comprehensive review on pipette-tip solid-phase extraction (PT-SPE) is lacking. This review (133 references) is mainly devoted to the development of different types of micro- and nanosorbent-based PT-SPE, including silica materials, carbon materials, organic polymers, molecularly imprinted polymers, and metal-organic frameworks. Each section mainly introduces and discusses the preparation methods, advantages and limitations of adsorbents, and their applications to environmental, biological, and food samples. This review also demonstrates the advantages of PT-SPE like convenience, speed, less organic solvent, and low cost. Finally, the future application and development trend of PT-SPE are prospected.

Recent Advances of Triazine-Based Materials for Adsorbent Based Extraction Techniques

This review mainly focused on the synthesis and properties of triazine-based materials as well as the state-of-the-art development of these materials in adsorption-based extraction techniques in the past 5 years, such as solid-phase extraction, magnetic solid-phase extraction, solid-phase microextraction and stir bar sorptive extraction, and the detection of various pollutants, including metal ions, drugs, estrogens, nitroaromatics, pesticides, phenols, polycyclic aromatic hydrocarbons and parabens. In the triazine-functionalized composites, triazine-based polymers and covalent triazine frameworks have been developed as the adsorbents with potential for environmental pollutants, mainly relying on the large surface area and the affinity of triazinyl groups with the targets. Triazine-based adsorbents have satisfactory sensitivity and selectivity towards different types of analytes, attributed from various mechanisms including π-π, electrostatics, hydrogen bonds, and hydrophobic and hydrophilic effects. The prospects of the materials for adsorption-based extraction were also presented, which can offer an outlook for the further development and applications.

Understanding the relationship between viral infections and trace elements from a metallomics perspective: implications for COVID-19

Recently, the World Health Organization (WHO) declared a pandemic situation due to a new viral infection (COVID-19) caused by a novel virus (Sars-CoV-2). COVID-19 is today the leading cause of death from viral infections in the world. It is known that many elements play important roles in viral infections, both in virus survival, and in the activation of the host's immune system, which depends on the presence of micronutrients to maintain the integrity of its functions. In this sense, the metallome can be an important object of study for understanding viral infections. Therefore, this work presents an overview of the role of trace elements in the immune system and the state of the art in metallomics, highlighting the challenges found in studies focusing on viral infections.

On-site sample preparation of trace aromatic amines in environmental waters with monolith-based multichannel in-tip microextraction apparatus followed by HPLC determination

A novel on-site preparation strategy for the determination of trace aromatic amines (AAs) in environmental waters was developed in the present study. To extract AAs effectively, 4-vinylbenzoic acid was copolymerized with ethylene dimethacrylate (ED)/divinylbenzene (DVB) in a pipette tip to obtain a new monolith-based adsorbent (MBA). The MBAs were employed as the extraction phases of home-made multichannel in-tip microextraction apparatus (ITMA) which was used to perform field sample preparation of AAs in different water samples followed by HPLC/DAD analysis. Due to the abundant functional groups, the prepared MBA displayed satisfying extraction performance for studied AAs. Under the optimized conditions, limits of detection varied from 2.1 to 26 ng/L with good coefficients of determination and precision. The recoveries for real water samples with different fortified concentrations were in the range of 78.1-119%, and the RSD values varied from 0.85 to 11%. In addition, the results achieved with the introduced method were well comparable to that obtained with conventional laboratory sample pretreatment process. Compared with existing approaches, the proposed method exhibits some merits such as s high throughput, good sensitivity and eco-friendliness. Most of important, the MBA/ITMA for on-site preparation avoids the storage and transportation of large volumes of waters, and guarantees the analytical accuracy of studied AAs.