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X-ray fluorescence (XRF) offers the advantage of performing measurements without damaging or consuming the sample, enabling rapid and simultaneous multi-element analysis. It has been widely applied in environmental monitoring, materials science, geology, and medicine, but not in water. Here, a novel method is proposed that combines energy-dispersive X-ray fluorescence spectroscopy (EDXRF) with prussian blue dispersed on solid sepiolite nanomaterials (PB/SEP) and an integrated enrichment-separation device to detect trace heavy metal ion Tl(I) in water environments. The water sample passes through the detachable enrichment component, and subsequently, PB/SEP is used as a solid adsorbent for the pre-enrichment of Tl(I) in the water sample. This process eliminates the cumbersome separation steps and saves analysis time. The research elucidates the impact of sample pH, flow rate, volume, and interfering ions on elemental recoveries, demonstrating that the proposed method offers a low detection limit of 0.057 μg/L, but also maintains high precision, with the RSD of less than 4.39 %. Furthermore, the PB/SEP magnetic nanocomposite was successfully applied to the tap water sample and river water sample with recoveries ranging from 93.5 % to 128.3 %, confirming the accuracy and practicality of the analytical method. [Display omitted] • A pre-enrichment process based on PB/SEP expands the application range of XRF from solids samples to water samples. • The process uses a detachable filter to achieve efficient and accurate enrichment of Tl (I). • The method significantly enhanced the detection limit of thallium for XRF at 0.057 μg/L. [ABSTRACT FROM AUTHOR]

In this work, a portable and 3D printing sulfur speciation analysis device was constructed, which effectively integrated with a vapor generation system, a microplasma chamber and a colorimetric unit. Point discharge microplasma was used for highly efficient oxidation of gaseous H 2 S to SO 2 , thus the simple and time-saving nonchromatographic speciation analysis of S2− and SO 3 2 − was achieved by simply adjusting the plasma "on" or "off". In this process, S2− were converted to volatile H 2 S by acidification reaction and then oxidized to SO 2 by microplasma, prior to a specific discoloring reaction with yellow fluorescein derivative, which effectively alleviated the interference from sample matrix and further improved the analytical sensitivity. The absorbance value of fluorescein derivative at 482 nm was used for quantitative analysis of S2− and SO 3 2 − . Under optimal conditions, the detection limit was calculated to be 6.22 μmol L−1 for both analytes in the concentration range of 30–210 μmol L−1, while 60 μmol L−1 analytes were recognizable by the naked eye. The whole 3D-printed device was miniaturized, portable and easy to operate, with fast response time (<1 min), which was only the size of an adult's palm and equipped with one 3.7 V lithium battery for power. This method has been successfully utilized to field analysis of toxic S2− and SO 3 2 − in real environmental water samples. A portable and 3D printing sulfur analytical device was constructed for the simple, time-saving and nonchromatographic field speciation analysis of S2− and SO 3 2 − in environmental water sample. [Display omitted] • A miniaturized, portable and 3D printing sulfur speciation analysis device. • Simple and time-saving nonchromatographic speciation analysis of S2− and SO 3 2 − . • Field speciation analysis of toxic S2− and SO 3 2 − in real environmental water samples. • Effective integration with a vapor generation system, a microplasma chamber and a colorimetric unit. [ABSTRACT FROM AUTHOR]

A detection method, named as nuclease protection-nucleic acid chromatography strip assay (NP-NACSA), was established to detect Prorocentrum minimum , a common harmful algal blooms-forming algal species. In this study, the developed NP-NACSA requires no nucleic acid amplification, but directly targets rRNA obtained from broken cells. After converting the target rRNA to DNA by nuclease protection, the resultant DNA is automatically analyzed by nucleic acid chromatography strip. The specificity, anti-interference ability and sensitivity of the established NP-NACSA were evaluated, respectively. The specificity test showed that NP-NACSA had good detection specificity, producing positive results only for the target algae and no cross-reaction with all control algal species. NP-NACSA has good anti-interference ability and its detection performance was not affected by the interfering algal species. The sensitivity test showed that the detection limit of NP-NACSA for RNA was 1.28 ng. The cellular detection limit of NP-NACSA for simulated natural water samples was 3.25 × 103 cells mL−1, which is lower than the density of HABs triggered by P. minimum (1 × 105 cells mL−1). Overall, the developed NP-NACSA is independent of special equipment, requires no nucleic acid amplification process, and can accomplish the specific, convenient, and intuitive detection of P. minimum. [Display omitted] • A NP-NACSA that can visually detect Prorocentrum minimum was developed. • The developed NP-NACSA is specific and sensitive. • NP-NACSA is competent for convenient and accurate analysis of samples. • This study provides a new method for the rapid detection of P. minimum. [ABSTRACT FROM AUTHOR]

Nitroaromatic compounds (NACs), as a kind of important chemical intermediates, are widely used in industrial productions. However, NACs have carcinogenic effect and their residues may pose harm to human health. Therefore, there is necessity to set up effective analytical method to monitor them in some environmental samples. However, because of their low concentrations in real samples, they need to be enriched by an effective adsorbent before the subsequent instrumental detection. In this work, a three-dimensional nitrogen-rich conjugated microporous polymer (DCT-Try-CMP) was synthesized with 3,6-dichloro-1,2,4,5-tetrazine and triptycene as monomers via Friedel-Crafts reaction. It presented a good adsorption capability for the NACs. After optimization, a solid-phase microextraction with DCT-Try-CMP fiber combined with gas chromatography-flame ionization detection for the quantitation of trace NACs in environmental water and soil samples was developed. The limits of detection of the method (S/N = 3) for environmental water and soil samples were 0.08–0.30 μg L−1 and 1.00–5.00 ng g−1, and the limits of quantification (S/N = 9) were 0.27–0.90 μg L−1 and 3.00–15.0 ng g−1, respectively. The linear quantification response ranges for the analytes were 0.27–200 μg L−1 and 3.00–1000 ng g−1 for water and soil samples, respectively. For water samples at the analytes concentrations of 5.00, 50.0 and 100 μg L−1, the method recoveries ranged from 82.2 % to 120 % and for soil samples at the concentrations of 15.0, 200 and 400 ng g−1, the method recoveries fell in the range from 80.2 % to 120 %. The method provides a sensitive and effective approach for monitoring trace NACs in environmental water and soil samples. A three-dimensional nitrogen-rich conjugated microporous polymer was prepared and used as solid-phase microextraction fiber coating for the first time. It demonstrated an excellent extraction performance for nitroaromatic compounds. [Display omitted] • A three-dimensional nitrogen-rich conjugated microporous polymer was synthesized. • It was used as a new fiber coating for the SPME of nitroaromatic compounds (NACs). • The fiber exhibited a good SPME performance for the NACs from real samples. • An analytical method coupling the SPME and GC-FID was developed. • The method is sensitive and effective for the quantification of trace NACs. [ABSTRACT FROM AUTHOR]

A new method is described for acetone (C(CH 3) 2 O) determination in water samples. The method is based on the reaction with 4-(dimethylamino)benzaldehyde (DMAB) in dimethyl sulfoxide (DMSO) in slightly basic medium, resulting in a highly fluorescent compound with fluorescent wavelengths undisturbed by other common fluorescent compounds. Experimental conditions were optimized (reagents concentrations, reaction time) to reach optimal sensitivity. For the analysis of aqueous samples, a preconcentration step of acetone by solid-phase extraction (SPE) followed by an elution step in DMSO was optimized using Isolute ENV + columns. A highly satisfactory low detection limit of 0.014 μM (0.8 μg L−1) was achieved by combining these two steps, with a linear range from 0.048 to 5 μM and relative standard deviations between 5.7 % and 6.9 %. The protocol was validated on complex real water samples such as river water and wastewater, and our fluorimetric method with DMAB was in good agreement with the reference LC-UV method with DNPH. [Display omitted] • New benzaldehyde reagent for sub-micromolar fluorescent detection of acetone. • SPE for acetone preconcentration in aqueous samples described for the first time. • Procedure validated on complex real water samples (river water and wastewater). [ABSTRACT FROM AUTHOR]

Double deposition and double stripping steps mode was used for the first time in combination with a flow system for anodic stripping voltammetric determination of As(III) ions. The proposed way of the voltammetric measurements leads to a decrease of the detection limit as compared to the values obtained using a traditional three-electrode system thanks to an initial preconcentration of the analyte on the first working electrode as well as the significant increase of the selectivity of As(III) determination thanks to the application of a flow system. Optimization of the analytical procedure was performed. The calibration curve of As(III) determination was a straight line in the range from 1 × 10−9 to 5 × 10−8 mol L−1. The estimated detection limit was 4.8 × 10−10 mol L−1 (deposition time of 120 s at both working electrodes). The repeatability of the proposed procedure calculated as RSD% for As(III) at a concentration of 1 × 10−8 mol L−1 was 3.8 % (n = 7). The tolerable limit of Cu(II) excess was significantly increased thanks to the solution exchange after the first deposition step. The correctness of the proposed procedure was confirmed by analysis of a real water sample and lake water certified reference material by obtaining satisfactory recovery values. [Display omitted] • Novel voltammetric procedure for As(III) determination was developed. • Double deposition and stripping step mode was combined with a flow system first-time. • Detection limit was decreased as compared to that obtained in three-electrode system. • Proposed way of measurements leads to a significant decrease of interference effects. • Impact of Cu(II) ions on As(III) analytical signal was significantly minimized. [ABSTRACT FROM AUTHOR]

Herein, a novel electrothermal desolvation (ED) introduction approach is developed to enhance the analytical sensitivity of the point discharge (PD)-based microplasma-optical emission spectrometric (PD-MIP-OES) system for detecting trace Cd, Zn, Pb and Mn in environmental water samples. Liquid samples are converted into aerosols through a miniature ultrasonic nebulizer, and subsequently desolvated by electric heating at 350 °C. The analytes obtained after condensation (referring to the smaller apertures aerosols and volatile analytes after ED and condensation) are excited and detected by PD-MIP-OES. For a 160 μL liquid sample, analysis is completed within 10 s, achieving a desolvation efficiency of 93 %. Under the optimized conditions, the detection limits for Cd, Zn, Pb and Mn are 1.3, 1.2, 2.4 and 2.1 μg L−1, respectively. Compared to traditional direct ultrasonic nebulization introduction, sensitivity increases by 17, 12, 10 and 14 times, respectively. The accuracy and practicality of the proposed method are verified by measuring certified reference material and several real water samples. The ED-enhanced PD-MIP-OES device presented is compact, easy to operate, and capable of rapid analysis, which provides a convenient and reliable tool for the field analysis of Cd, Zn, Pb and Mn in environmental water samples. [Display omitted] • A novel electrothermal desolvation (ED) introduction approach is proposed. • The ED-enhanced PD-OES device achieved a desolvation efficiency of up to 93 %. • Detection sensitivity increases by 10–17 times compared with direct ultrasonic nebulization introduction. [ABSTRACT FROM AUTHOR]

A straightforward approach to fabricating robust and versatile solid-phase microextraction (SPME) fibers is crucial for the extensive research and application of this notable sample preparation technique. Herein, we proposed a strategy for preparation of oxidative polyacrylonitrile (O-PAN) and O-PAN/ZIF-67 nanofiber-based SPME coatings by wrapping an electrospinning membrane on the stainless-steel wire, following with thermal oxidation at 300 °C. The shrinkage of membrane during thermal treatment resulted in the nanofibers being securely affixed to the stainless-steel wire, thereby creating a robust nanofiber-based SPME fiber. Furthermore, the characterizations results indicated that the thermal oxidation significantly enhanced the generation of oxygen-/nitrogen-containing groups within the nanofibers, which were conducive to the adsorption for the analytes. Given the exceptional properties, the proposed O-PAN/ZIF-67 coating was applied to extract and analyze polychlorinated biphenyls (PCBs) pollutants coupled with GC-MS, and exhibited superior extraction performances. The proposed analytical method presented a wide linear range spanning concentrations from 0.5 to 2500 ng L−1, with a low detection limit ranging between 0.029 and 0.093 ng L−1. Additionally, it demonstrated good precision, as evidenced by a relative standard deviation of 4.5 %–8.1 %, and was effectively utilized for the analysis of real water samples. This study introduced a novel, simple, and versatile methodology for the fabrication of nanofiber-based SPME coatings, offering a significant advancement in the field. [Display omitted] • O-PAN composite nanofiber-based SPME coatings were fabricated by wrapping and thermal oxidation strategy. • Thermal treatment-induced shrinkage of PAN nanofibers facilitated formation of robust SPME coating. • Generation of oxygen groups during thermal oxidation and doping of ZIF-67 enhanced the extraction performance. • The proposed SPME coating was applied for efficient extraction of polychlorinated biphenyls pollutants. [ABSTRACT FROM AUTHOR]

The development of high-performance sensors for rapidly detecting acetylacetone (AP) in water samples is necessary because its release into the environment can result in many vital problems for human health and environment. Herein, we first designed a hybrid by integrating HOF with ZIF-8 through a sequential growth strategy. By separately introducing blue-emitting SiQDs and green- and red-emitting Tb3+ and Eu3+ into ZIF-8 and HOF, the resultant ZIF-8@SiQDs@HOF@Eu3+@Tb3+ comprised three emission peaks at 484, 545 and 620 nm, all of which could be employed as switch-off responsive peaks to low concentrations of AP with a detection limit of 0.79 ppm. However, in environments with high concentrations of AP, a turn-on signal at 484 nm was observed. Thereupon, the ratiometric fluorescence intensity of the ternary emission varied within different concentration ranges, accompanied by the fluorescence color evolution from red to salmon to plum to purple to final blue. Moreover, a portable sensing film was fabricated for rapid warning, sensitive and visual determination of AP in complicated environments. Therefore, this triple-emission sensor with wide color variations and strong anti-interference advantages could promote further research to improve the selectivity, sensitivity and inherent self-correction of multimodal fluorescence detection and the ease of sensing operation. A triple-emission sensor ZIF-8@SiQDs@HOF@Eu3+@Tb3+ could recognize a low concentration of AP with turn-off signal and a high concentration of AP with turn-on fluorescence. [Display omitted] • A triple-emission ZIF-8@SiQDs@HOF@Eu3+@Tb3+ sensor for AP was synthesized. • The detection limit of AP was 0.79 ppm. • The sensor could recognize different concentrations of AP through different signals. • The fluorescence color emerged from red to salmon, plum to purple to final blue. • A portable sensing film was fabricated for fast detection of AP. [ABSTRACT FROM AUTHOR]

The presence of fluoroquinolones (FQs) residues in food and the environment has prompted concerns regarding food safety and public health. Consequently, it is of great significance to analyze the types and levels of FQs present. However, the majority of studies have concentrated on the specific detection of individual FQs, with a notable absence of high-throughput and rapid analysis methods for the simultaneous detection of multiple FQs that may coexist in food and the environment. Hereon, a triple-channel sensor array was successfully constructed utilizing fluorescent carbon dots (TA-CDs), with the assistance of Cu2+ and Fe3+, for the qualitative discrimination and quantitative detection of eight types of FQs. The sensor array can distinguish between different concentrations of FQs and various mixtures of FQs, as well as 100 % accuracy in the discrimination of unknown samples. Impressively, the sensor platform can quantitatively detect FQs in animal-derived foods, such as honey, milk, eggs, and pork, as well as in water samples. This research has the potential to be extended to other analytes with similar chemical structures or properties. [Display omitted] • A sensor array is constructed using carbon dots with the assistance of Cu2+ and Fe3+. • The sensor array can qualitatively and quantitatively analyze fluoroquinolones (FQs). • The sensor array can discriminate various concentrations of FQs and FQs mixtures. • The sensor array has strong anti-interference capability in complex environments. [ABSTRACT FROM AUTHOR]

As an important ROS species participating in various physiological and pathological processes, high level of hypochlorite (ClO−) poses significant health and safety concerns, necessitating efficient detection methods. Herein, this study introduces a water-soluble fluorescent nanoprobe Nano-SJD , effectively detect ClO− in both food samples and living cells. The small molecular probe SJD with N, N-dimethylthiocarbamyl (DMTC) as recognition moiety was constructed based on a naphthalene derivative. To further improve the water solubility, SJD was assembled with an amphiphilic copolymer (mPEG-DSPE) to prepare a water soluble fluorescent nanoprobe Nano-SJD. Fortunately, the nanoprobe preserves the excellent properties of small molecules and performs very well optical response to ClO− in aqueous solution, possessing the advantages including ultra-rapid response (within 1 s), minimal interference, low detection limits (0.39 μM) and good pH stability. What's more important, we have also developed smartphone-compatible test paper strips for convenient on-site detection of ClO− in real-water samples. Additionally, the robust fluorescent imaging behavior of Nano-SJD for visualization of ClO− in living cells highlights its broad potential in biosystem applicability. A self-assembled nanoprobe for ultra-fast (within 1 s) detection of hypochlorite in pure water, and its application in living cells, food and real water environmental systems. [Display omitted] • Nano-SJD exhibits ultra-fast response (within 1 s) for hypochlorite. • Detection of hypochlorite performs well in 100 % PBS buffer (pH = 7.4). • Portable and quantitative detection of hypochlorite levels in real water samples. • This probe can be employed for real-time monitoring hypochlorite in living cells. [ABSTRACT FROM AUTHOR]

Catechol, a polyphenolic molecule and significant organic chemical intermediate, is a highly dangerous environmental contaminant due to its unpredictable nature and potential harm to both humans and the environment. This study presents the development of Sn MOF@rGO-650, identified as a hollow cube by SEM and TEM, created by carbonizing rGO on the surface of Sn MOF after in situ encapsulation. The Sn MOF@rGO-650 modified glassy carbon electrode was successfully constructed for the electrochemical detection of catechol. Under optimal conditions, the sensor exhibited a detection limit of 33 nM, a linear range of 0.20 μM–28 μM, and good long-term stability and reproducibility. This work proves for the first time that Sn MOF@rGO-650 composites can effectively detect catechol in real environmental water samples, achieving recoveries between 95.7 % and 104.8 %, and is validated in UV spectroscopy, which highlights its potential for practical applications. [Display omitted] • rGO effectively modulates the particle size of Sn MOF and retain its structure. • Composite has a distinctive structure with high specific surface area and porosity. • The electrochemical sensor has a surprisingly low detection limit for catechol. • The sensor accurately detects trace catechol in real tap water samples. [ABSTRACT FROM AUTHOR]

In this work, a novel molecularly imprinted electrochemical aptasensor (MIEAS) was developed for highly selective detection of dexamethasone (Dex) in natural water environment. Gold nanoparticles (AuNPs) modified by nitrogen doped molybdenum carbide-graphene (N–Mo 2 C-Gr) were employed as the supports, where N–Mo 2 C-Gr improved the conductivity of the electrode and provided a larger specific surface area to polymerize more active substances. Using Dex as template molecule, o-phenylenediamine (o-PD) as the chemical functional monomer and aptamer as the biofunctional monomer, a molecularly imprinted polymer (MIP) membrane with Dex specific recognition sites was formed by electropolymerization. Due to the synergistic effect of MIP and aptamers, the as-prepared MIEAS exhibited a decent linear relationship to Dex detection within a relatively wide range of 10−13 – 10−5 M, and the detection limit was 1.79 × 10−14 M. The recovery in actual water and tablet samples is satisfactory, which confirms the potential application prospects of this sensor in the determination of Dex. [Display omitted] • A molecularly imprinted electrochemical aptasensor was designed for the detection of Dex based on dual recognition elements. • Aptamer was used as the biofunctional monomer and o-phenylenediamine (o-PD) was used as the chemical functional monomer. • The sensor exhibited higher selectivity than that with one recognition element. • The sensor was successfully applied in actual water and tablet samples. [ABSTRACT FROM AUTHOR]

In this study, a novel technique utilizing vortex-assisted dispersive liquid-liquid microextraction with magnetic deep eutectic solvents (MDESs) was established and coupled with HPLC-UV to analyze six primary aromatic amines (PAAs). A novel hydrophobic MDES prepared from trioctylphosphine oxide, octanol, and CoCl 2 was used as the extractant, which could be dispersed uniformly during extraction, then floated onto the sample surface and re-aggregated into a single drop spontaneously after the extraction. The variables influencing the efficiency of the extraction process were investigated. When performing under the optimal extraction conditions, this method exhibited excellent linearity, low limits of detection (0.2–0.9 ng mL−1), and high precision (RSD ≤ 8.3 %). The enrichment factors ranged from 56 to 182. Satisfactory recoveries in the range of 91.6–109.2 % with RSDs < 7.1 % were obtained from three apple juices and three environmental water samples. The greenness and practicality of the developed method were assessed by AGREE, AGREEprep, and blue applicability grade index metric tools. Overall, the established procedure demonstrated its simplicity, speediness, environmental friendliness, and effectiveness in analyzing PAAs from aqueous matrices. [Display omitted] • A series of hydrophobic magnetic deep eutectic solvents (HMDESs) were synthesized. • The physicochemical and thermal properties of synthesized HMDESs were characterized. • A vortex-assisted HMDES-based DLLME method was developed. • The proposed method is simple, fast, robust, cost-effective, eco-friendly and highly sensitive. • This method realizes simultaneous pre-concentration of 6 primary aromatic amines from juice and water matrices. [ABSTRACT FROM AUTHOR]

This study was designed to develop a rapid and sensitive method for quantifying legacy and emerging per- and polyfluoroalkyl substances (PFASs) in environmental samples with solid-phase microextraction (SPME) coupled with mass spectrometry (MS). An innovative SPME probe was fabricated via in situ polymerization, and the probe coating was optimized with response surface methodology to maximize the fluorine–fluorine interactions and electrostatic properties and ensure high selectivity for the target PFASs with enrichment factors of 48–491. The coupled SPME and MS provided a rapid and sensitive method for analyses of PFASs, with excellent linearity (r ≥ 0.9962) over the concentration range 0.001–1 μg/L and remarkably low detection limits of 0.1–13.0 ng/L. This method was used to analyze trace PFASs in tap water, river water, and wastewater samples and proved to be a simple and efficient analytical method for selective enrichment and detection of contaminants in the environment. [Display omitted] • IPS-SPME probes were developed by an in-situ polymerization approach for PFASs. • In-situ polymerized SPME probe optimized for high PFASs selectivity. • IPS-SPME-NanoESI-MS for direct, rapid trace PFASs detection in water samples. • Validated method ensures precise quantification of legacy and emerging PFASs. [ABSTRACT FROM AUTHOR]

Quizalofop-p-ethyl is a widely used herbicide that also poses a risk to human health and environmental safety. However, there is still a lack of simple and in-situ detecting method for quizalofop-p-ethyl so far. In this work, the fluorescent sensor was firstly developed on detection of quizalofop-p-ethyl based on cyanostilbene-pyridine macrocycle (CPM). CPM was prepared by the "1 + 1" condensation of pyridine-substituted cyanostilbene derivative with 4,4'-Bis(chloromethyl)biphenyl in 68 % yield. The weak fluorescence of CPM in aqueous media transferred to strong orange fluorescence after sensing quizalofop-p-ethyl. This sensing behavior exhibited high selectivity among 28 kinds of herbicides and ions. The limitation of detection (LOD) was 2.98 × 10−8 M and the limitation of quantification (LOQ) was 9.94 × 10−8 M (λ ex = 390 nm, λ em = the maximum emission between 512 nm and 535 nm) with a dynamic range of 0.01–0.9 eq. The binding constant (Ka) of quizalofop-p-ethyl to the sensor CPM was 3.2 × 106 M−1. The 1:1 sensing mechanism was confirmed as that quizalofop-p-ethyl was located in the cavity of CPM , which enhanced aggregating effect and reduced the intramolecular rotation of aromatic groups for better AIE effect. The sensing ability of CPM for quizalofop-p-ethyl had been efficiently applied in test paper experiments, agricultural product tests and real water samples, revealing that CPM has good application prospect for simple and in-situ detection of quizalofop-p-ethyl in real environment. [Display omitted] • The first fluorescent sensor for herbicide quizalofop-p-ethyl was presented. • The sensor exhibited the "turn-on" orange fluorescence on sensing quizalofop-p-ethyl. • This detection displayed the high sensing selectivity and sensitivity. • The detecting limitation was 2.98 × 10−8 M. • The sensor was applied for detecting quizalofop-p-ethyl in real samples. [ABSTRACT FROM AUTHOR]

As an essential chemical intermediate, catechol (CC) residues may have adverse effects on human health. Herein, an effective and facile photoelectrochemical sensor platform based on MgIn 2 S 4 /CdWO 4 composite is constructed for monitoring CC. MgIn 2 S 4 increases light absorption range and activity, while CdWO 4 enhances photoelectronic stability, and the type-II heterojunction formed can significantly enhance photocurrent response. Due to the autoxidation process, CC is converted into oligomeric products, which increase the spatial site resistance and attenuate the overall photocurrent response. It is worth noting that the cauliflower-like structure of MgIn 2 S 4 can provide a large specific surface area, and the presence of Mg2+ promotes autoxidation, thus providing a suitable condition for detecting CC. Under optimal conditions, the MgIn 2 S 4 /CdWO 4 /GCE photoelectrochemical sensor has a prominent linear relationship in the range of CC concentration from 2 nM to 7 μM, with a limit of detection of 0.27 nM. With satisfactory selectivity, excellent stability, and remarkable reproducibility, this sensor provides a crucial reference value for effectively and rapidly detecting pollutants in environmental water samples. [Display omitted] • The MgIn 2 S 4 /CdWO 4 type-Ⅱ heterojunction can enhance the photocatalytic response. • The presence of Mg2+ in heterojunction promotes the autoxidation of catechol. • The photoelectrochemical sensor has an astoundingly low LOD for catechol. • The sensor can accurately detect trace amounts of catechol in actual water sample. [ABSTRACT FROM AUTHOR]

A film composed of agarose and graphene (G) and magnetic nanoparticles (G-MNPs) is proposed as a sorbent for the extraction and determination of medroxyprogesterone (MED), levonorgestrel (LEV), norethisterone (NOR) and progesterone (PRO) in natural water samples. Both the preparation of the film and the extraction procedure were optimized. The optimal extraction parameters were as follows: isopropyl alcohol as activation solvent, sample pH value of 3.0, extraction time of 30 min, 1.00 mL of acetonitrile as eluent, elution time of 5 min and sample volume of 100.00 mL. HPLC with photodiode array detector was used for the separation and determination. The method presented a linear range between 2.50 and 75.0 μg L−1 for all analytes, and the LODs were between 1.40 and 1.80 μg L−1. The method was applied to natural water samples, obtaining satisfactory recovery values (75–111 %). In conclusion, for the immobilization of the G-MNPs, agarose was used, which is a non-toxic, renewable and biodegradable material. The G-MNPs-agarose film was reused up to 70 times, without losing its extraction capacity significantly and presenting excellent sorbent properties, which allow the extraction and preconcentration of the progestogens under study. [Display omitted] • A single, reusable and biodegradable G-MNPs-agarose film was prepared for progestogens extraction. • The film presented excellent mechanical properties and high extraction efficiency. • The film was reusable for 70 times without losing its extraction capacity. [ABSTRACT FROM AUTHOR]

Laser-induced breakdown spectroscopy (LIBS), as an elemental composition analysis technique, has many unique advantages and great potential for applications in water detection. However, the quality of LIBS spectral signals, such as signal-to-noise ratio and stability, is often poor due to the matrix effects of water, limiting its practical performance. To effectively remove the inherent weak radiation in experimental spectral data that can be easily mistaken for noise, this paper proposes a denoising algorithm for processing spectral data using a self-built blank sample spectral database of deionized water samples, and designs a complete data processing workflow. It includes steps such as blank sample data screening, internal standard correction, blank sample correction, and spectral smoothing. Against the backdrop of marine applications, experimental spectral data for target elements Na, Mg, Ca, K, Sr, and Li were processed with this algorithm. The results show that after algorithm processing, the spectral quality was significantly improved, with the signal-to-noise ratio and detection limits of various elements improved by at least one order of magnitude. The signal-for Li increased by up to 36 times, and the detection limit for K decreased by up to 25.2 times. Additionally, tiny spectral peaks that could not be observable in the original spectral data could be effectively extracted after processing. From a technical implementation perspective, the database establishment and data process are simple and practical, with universal applicability. Therefore, this method has good potential and wide foregrounds in many other water sample LIBS detection technologies. [Display omitted] • Use blank sample removal method for noise reduction in LIBS spectral preprocessing. • The noise reduction effect is significant. Compared with the original spectra of six target elements, the spectral data processed by this algorithm shows significant noise reduction, achieving a SNR of up to 36 times. • This method effectively extracts small spectral peaks that cannot be detected in the original spectrum. • For multiple elements, the detection limit of all target elements can be increased by at least one order of magnitude. [ABSTRACT FROM AUTHOR]

Antibiotics in aquatic environments raise health concerns. Therefore, the rapid, on-site, and accurate detection of antibiotic residues is crucial for protecting the environment and human health. Herein, a dumbbell-shaped iron (Fe3+)-dopamine coordination nanozyme (Fe-DCzyme) was developed via an iron-driven self-assembly strategy. It exhibited excellent peroxidase-like activity, which can be quenched by adding l -cysteine to prevent Fe3+/Fe2+ electron transfer but restored by adding norfloxacin. Given the 'On-Off-On' effect of peroxidase-like activity, Fe-DCzyme was used as a colourimetric sensor for norfloxacin detection, and showed a wide linear range from 0.05 to 6.00 μM (R 2 = 0.9950) and LOD of 27.0 nM. A portable smartphone-assisted detection platform using Fe-DCzyme was also designed to convert norfloxacin-induced color changes into RGB values as well as to realise the rapid, on-site and quantitative detection of norfloxacin. A good linear relation (0.10–6.00 μM) and high sensitivity (LOD = 79.3 nM) were achieved for the smartphone-assisted Fe-DCzyme detection platform. Its application was verified using norfloxacin spiking methods with satisfactory recoveries (92.66%–119.65%). Therefore, the portable smartphone-assisted Fe-DCzyme detection platform with low cost and easy operation can be used for the rapid, on-site and visual quantitative detection of antibiotic residues in water samples. [Display omitted] • A nanozyme (Fe-DCzyme) was designed by metal-driven self-assemble strategy. • Fe-DCzyme sensor can naked-eye and rapid detection of norfloxacin. • A portable smartphone-assisted platform integrated with Fe-DCzyme was designed. • The portable platform can on-site and visual quantitative detection of norfloxacin. [ABSTRACT FROM AUTHOR]

The importance of water in all biological processes is undeniable. Ensuring access to clean and safe drinking water is crucial for maintaining sustainable water resources. To elaborate, the consumption of water of inadequate quality can have a repercussion on human health. Furthermore, according to the instability of tap water quality, the consumption rate of bottled water is increasing every day at the global level. Although most people believe bottled water is safe, it can also be contaminated by microbiological or chemical pollution, which can increase the risk of disease. Over the last decades, several conventional analytical tools applied to analyze the contamination of bottled water. On the other hand, some limitations restrict their application in this field. Therefore, biosensors, as emerging analytical method, attract tremendous attention for detection both microbial and chemical contamination of bottled water. Biosensors enjoy several facilities including selectivity, affordability, and sensitivity. In this review, the developed biosensors for analyzing contamination of bottled water were highlighted, as along with working strategies, pros and cons of studies. Challenges and prospects were also examined. [Display omitted] • Recent developments of (bio)-sensors for the determination of contaminants in bottled drinking water. • Detection of microbiological and non-biological contamination of bottled drinking water. • The role of nanomaterials, bioreceptors and techniques in the development of (bio)-sensors. [ABSTRACT FROM AUTHOR]

Nanoplastics (NPs) have been identified as an emerging concern for the environment and our food chains in recent years. Monitoring the concentration and size of nanoplastics is essential to assess the potential risks that nanoplastic particles may pose. In this study, we presented a multi-technique based analytical platform to identify, characterize and quantify nanoplastics in water samples through a combination of sample pre-concentration, asymmetric flow field-flow fractionation coupled with multi-angle light scattering (AF4-MALS) and pyrolysis-GC/MS (Py-GC/MS). Models for predicting NPs concentration and particle number in unknown samples were established and validated using NPs standards of known size and AF4-MALS response. Py-GC/MS was applied for further identification of polymer type and quantification of mass concentration. Filtration conditions for pre-concentration were optimized to ensure a high recovery rate with minimal effect on original particle size. The addition of 0.05% SDS prior to filtration, using controlled filtration procedures, effectively improved the recovery. Furthermore, this study demonstrates the application of the analytical platform for the characterization and quantification of different nanoparticles (e.g. spiked PMMA and PS NPs) in the size range 60 nm–350 nm with detection limits down to 0.01 ppm in water samples. The established analytical platform can fill an analytical gap by offering a solution for quantifying size-resolved mass concentrations of nanoplastics and providing comprehensive data on size distribution, particle number and mass quantification with high sensitivity for detection. [Display omitted] • Precisely quantify nanoplastics with comprehensive details. • High sensitivity for nanoplastics detection and characterization. • Provide a solution for quantifying size-resolved concentrations of nanoplastics. [ABSTRACT FROM AUTHOR]

The aim of the current study was to separate and determine arsenic in water and fish samples using a novel and green solidified floating organic drop microextraction (SFODME), which is based on switchable hydrophilicity solvent (SHS)-assisted procedure followed by hydride generation atomic absorption spectrometry (HG-AAS). The 4-((2-hydroxyquinoline-7-yl)diazenyl)-N-(4-methylisoxazol-3-yl)benzene sulfonamide (HDNMBA) and tertiary amine (4-(2-aminoethyl)-N,N-dimethylbenzylamine (AADMBA) were used as ligand and SHS, respectively. The use of SHS promotes quantitative extraction of arsenic complexes into an extraction solvent (1-undecanol). Some factors that impact extraction recovery were studied. Under optimal conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.005 μg L−1 and 0.015 μg L−1, respectively. The calibration graph was linear up to 900.0 μg L−1 arsenic, with the enrichment factor is 267. The proposed SHS-SFODME methodology for arsenic quantification in water and fish samples was successfully implemented. The environmental friendliness and safety of proposed method were approved by the Analytical Greenness Calculator (AGREE) and the Blue Applicability Grade Index (BAGI) tools. [Display omitted] • A switchable hydrophilicity solvent-assisted solidified floating organic drop microextraction (SHS-SFODME) has been proposed. • SHS-SFODME coupled to HG-AAS (SHS-SFODME-HG-AAS) for Arsenic detection. • The SHS as co-ligand and disperser solvent used. • The SHS-SFODME-HG-AAS method was successfully applied to Arseniс traces analysis. • Greenness and blueness were determined. [ABSTRACT FROM AUTHOR]

To determine metronidazole in water samples, we developed an environmentally friendly, efficient, and straightforward ferrofluid-based liquid-liquid microextraction sample pretreatment technique. It is coupled with a high-performance liquid chromatography-ultraviolet analytical technique known for its sensitivity, speed, and precision. The magnetic separation of metronidazole-containing ferrofluid from the matrix was effortlessly achieved through the application of an external magnetic field, eliminating the need for centrifugation. Response surface optimization was employed to systematically determine the key experimental parameters influencing extraction efficiency, including pH, NaCl concentration, ferrofluid volume, and vortex duration. With a low detection limit (0.116 ng mL−1), a broad linear range between 0.5 and 700 ng mL−1 was achieved at optimal conditions. Additionally, acceptable spiking recoveries (94.3–97.3 %) and RSD values (≤3.7 %) for intra- and inter-day precision were attained in water samples. In conclusion, the effectiveness of the vortex and ferrofluid combination, along with the convenience of collection and elimination of the need for centrifugation, bestows a highly valuable technique for determining metronidazole in water samples. [Display omitted] • New green deep eutectic solvent-based ferrofluid • Highly efficient preconcentration and determination of metronidazole • Vortex-assisted liquid-phase microextraction under experimental design optimization [ABSTRACT FROM AUTHOR]

This work describes the development of a microfluidic paper-based analytical device (μPAD) for the determination of copper in fresh and marine waters. A functionalized rhodamine-based chelator was synthesized and used as a chromogenic reagent, forming a highly intense pink complex with the analyte. The aim was to create a paper device that offers optimal performance and provides in-situ , rapid and cost-effective analysis in line with World Health Organization guidelines. The influence on the determination of several physical and chemical parameters was evaluated aiming to achieve the best performance. Under optimised conditions, a linear correlation was established in the range of 0.05–0.50 mg L−1 of copper, with a limit of detection of 10 μg L−1. The accuracy of the proposed method was assessed by comparing the results obtained with the developed μPAD and the results obtained with Inductively Coupled Plasma measurements (RE < 10 %). Recovery studies were also performed using different types of water samples with no need for any prior sample pre-treatment: tap, well, river and seawater. The average recovery percentage of 101 % (RSD = 4.3 %) was obtained, a clear indication of no multiplicative matrix interferences. [Display omitted] • Copper determination in waters using a handheld-size microfluidic paper-based device incorporating a synthesized chelator. • Quantification of copper validated by comparison with Inductively Coupled Plasma – Optical Emission Spectrometer (ICP-OES). • Environmentally friendly assembly as there is no need for a wax printer. [ABSTRACT FROM AUTHOR]

A microfluidic paper-based analytical device (μPAD) utilizing gas-diffusion separation and solid-phase reduction was developed for the first time for the determination of both ammonium and nitrate, which are the dominant inorganic nitrogen species in environmental waters. The device consists of 3 filter paper layers accommodating the sample, reagent and detection zones. The reagent zone is separated from the detection zone by a semipermeable hydrophobic membrane and acts as a solid-phase reactor where nitrate is reduced to ammonia by Devarda's alloy microparticles, integrated into a μPAD for the first time. The detection zone incorporates the acid-base indicators bromothymol blue (BTB) or nitrazine yellow (NY) and changes colour in two steps. Initially the colour change is caused by ammonia generated by the reaction of ammonium and sodium hydroxide in the sample zone. This colour change is followed by a subsequent colour change as a result of the ammonia produced by the reduction of nitrate by the Devarda's alloy microparticles. The corresponding reflectance value changes are used for the quantification of the two inorganic nitrogen species in the ranges 6.5–100.0 or 2.1–15.0 mg N L−1 for ammonium and 18.2–100.0 or 4.2–15.0 mg N L−1 for nitrate when BTB or NY are used, respectively. Under optimal conditions the limits of quantification of ammonium and nitrate in the case of BTB were determined as 6.5 and 18.2 mg N L−1, respectively, while the corresponding values in the case of NY were found to be 2.1 and 4.2 mg N L−1. The newly developed μPAD was stable for 62 days when stored in a freezer and 1 day at ambient temperature. It was validated with a certified reference material and successfully applied to the determination of ammonium and nitrate in spiked environmental water samples and soil extracts. [Display omitted] • A microfluidic paper-based analytical device (μPAD) for inorganic N is proposed. • NH 4 + and NO 3 − are determined as NH 3 ; NO 3 − is reduced to NH 3 by Devarda's alloy. • NH 3 is separated across a Teflon membrane by a gas-diffusion approach. • Detection is based on colour change of bromothymol blue or nitrazine yellow. • The μPAD is validated with a certified reference material and spiked water samples. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are high-profile organic pollutants to be poisonous, carcinogenic, and mutagenic, and widely distributed at trace levels in the environment. In order to effectively enrich PAHs, two stable covalent organic frameworks (COFs, TAPT-OMe-PDA and TPB-DMTP) were prepared by combining 2,4,6-tri(4-aminophenyl)-1,3,5-triazine (TAPT) and 1,3,5-tri(4-aminophenyl) benzene (TAPB) with 2,5-dimethoxy-phenyl-1,4-diformaldehyde (OMe-PDA), respectively. Even though the surface area of TAPT-OMe-PDA was much lower than that of TPB-DMTP, it still demonstrated much better extraction efficiencies towards PAHs as the solid phase microextraction (SPME) coating. Therefore, the TAPT-OMe-PDA coated fiber was coupled with gas chromatography-mass spectrometry (GC-MS) to establish a practical and sensitive method, after the extraction parameters (extraction time, extraction temperature, desorption temperature, desorption time, salt concentration and pH) were optimized. This developed analytical method showed wide linear ranges, low limits of detection, good repeatability and reproducibility. Finally, five PAHs in three water samples were detected and quantified precisely (2.72–38.7 ng·L-1) with satisfactory recoveries (88.3%–118%). [Display omitted] • Two COFs (TAPT-OMe-PDA and TPB-DMTA) were successfully prepared. • TAPT-OMe-PDA and TPB-DMTA were fabricated as uniform SPME coatings. • The TAPT-OMe-PDA demonstrated better extraction efficiencies for PAHs than TPB-DMTA. • Trace PAHs in environmental water were determined by the developed sensitive method. [ABSTRACT FROM AUTHOR]

Large–size spherical sorbents with particle size of 10–50 μm are widely applied in separation fields, however it is still a great challenge to synthesize such large–size spherical covalent organic framework (COF). In this work, a type of large–size porous 3D COF was size–controablly synthesized via a two–step strategy, in which a large–size porous 3D spherical polymer was prepared first through a Pickering emulsion polymerization using nano silica as the stabilizer, and subsequently it was converted into porous spherical 3D COF by a solvothermal method. The as–prepared porous spherical COF (COF–320 as a model) showed size–controllable uniform spherical morphology within 15–45 μm, large specific surface area, fine crystalline structure, and good chemical stability. When used as the sorbent for dispersive solid–phase extraction (d–SPE) of bisphenol F (BPF), the porous spherical COF–320 (15 μm) displayed high adsorption capacity (Q max = 335.6 mg/g), high enrichment factor (80 folds), and good reusability (at least five cycles). By coupling the d–SPE method to HPLC, a new analytical approach was developed and successfully applied to the determination of trace BPF in two water samples, an orange juice and a standard sample with recoveries of 96.0–102.2 % (RSD = 1.1–1.5 %), 95.7–97.4 % (RSD = 1.4–4.4 %) and 98.7 % (RSD = 2.3 %), respectively. The limit of detection (S/N = 3) and limit of quantification (S/N = 10) were 0.1 and 0.3 ng/mL, respectively. The new synthesis strategy opens a viable way to prepare large–size porous spherical COFs, and the developed analytical method can be potentially applied to sensitively detect the trace BPF in water samples and beverages. [Display omitted] • Large-size porous spherical 3D COFs were size-controllably prepared within 15–45 μm. • A Pickering emulsion polymerization and a solvothermal method used for synthesis. • Such spherical COF was used for d-SPE of BPF in water samples and orange juice. • This COF showed high binding ability, high enrichment factor and good reusability. • The d-SPE-HPLC-UV method displayed high sensitivity for detection of trace BPF. [ABSTRACT FROM AUTHOR]

Hypochlorite/hypochlorous acid (ClO−/HOCl) is a biologically crucial reactive oxygen species (ROS), produced in living organisms and has a critical role as an antimicrobial agent in the natural defense system. However, when ClO− is produced excessively, it can lead to the oxidative damage of biomolecules, resulting in organ damage and various diseases. Therefore, it is imperative to have a straightforward, quick and reliable method for over watching the minimum amount of ClO− in different environments. Herein, a new probe TTM , containing thienothiophene and malononitrile units, was developed for exceptionally selective and sensitive hypochlorite (ClO−) detection. TTM demonstrated a rapid "turn-on" fluorescence response (<30 s), naked-eye detection (colorimetric), voltammetric read-out with anodic scan, low detection limit (LOD = 0.58 μM and 1.43 μM for optical and electrochemical methods, respectively) and applicability in detecting ClO− in real water samples and living cells. This study represents one of the rare examples of a small thienothiophene-based molecule for both optical and electrochemical detections of ClO− in an aqueous medium. [Display omitted] [ABSTRACT FROM AUTHOR]

A colorimetric and fluorescent sensor, selective for Cu2+ ions, was synthesized in two steps using a rhodamine-based compound attached to the semicarbazide-picolylamine moiety (RBP). Spectroscopic measurements, including UV–Vis absorption and fluorescence emission, were conducted in the semi-aqueous medium containing acetonitrile/4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, denoted as MeCN/HEPES buffer (2:8, v/v, pH 7.0). The sensor exhibited high selectivity towards Cu2+ ions compared to other cations and demonstrated remarkable sensitivity towards Cu2+ ions, with a limit of detection at the nanomolar level. The calculated transitions indicated a 1:1 stoichiometric binding of RBP to Cu2+ ions based on a 4-coordination mode involving additional chelation in the semi-aqueous medium. The sensing mechanism for the detection of Cu2+ ions was investigated using high-resolution mass spectroscopy. The sensor could be employed as a real-time chemosensor for monitoring Cu2+ ions. Furthermore, the sensor has the potential for utilization in the detection of Cu2+ ions in actual water samples with the high precision and accuracy, as indicated by the small relative standard derivation values. The 50th percentile cytotoxicity concentration of RBP was found to be 22.92 μM. Additionally, the fluorescence bioimaging capability of RBP was demonstrated for the detection of Cu2+ ions in human hepatocellular carcinoma (HepG2) cells. [Display omitted] • A rhodamine-semicarbazide sensor was synthesized for Cu2+ ion via hydrolysis pathway. • A semicarbazide-pyridine unit as the binding site for Cu2+ was studied by TDDFT method. • The detection limit of the sensor was 5.8 nM, lower than the WHO value in drinking water. • The sensor rapidly detected Cu2+ in 1 min and in an buffer medium of pH 4−9. • The sensor could detect Cu2+ in real water samples and Hep-G2 cells. [ABSTRACT FROM AUTHOR]

In this work, we developed a simple, comprehensive, and effective device and procedure for sample preparation based on dispersive micro-solid phase extraction (d-μ-SPE) for the simultaneous determination of 30 polycyclic aromatic compounds or PACs (including 16 polycyclic aromatic hydrocarbons (PAHs), 3 quinones, and 11 nitro-PAHs) in water samples. The extraction/preconcentration step was carried out in a customized glass device (20–250 mL) using C 18 as the sorbent. A mini-UniPrep syringeless filter was used as a desorption device, which allowed one-step desorption, filtration, and injection. The main factors affecting the d-μ-SPE were optimized using the Doehlert design. The optimal d-μ-SPE conditions were 100 mg of C 18 , 32 min of extraction at 1000 rpm, and 20 min of sonication (at the desorption step). The limit of detection (LOD) for PAHs and nitro-PAHs ranged from 0.8 ng L−1 (phenanthrene) to 1.5 ng L−1 (indene [1,2,3-cd]pyrene) and from 300 ng L−1 (2-nitrofluorene) to 500 ng L−1 (2-nitrobiphenyl), respectively. For quinones, it varied from 1.12 μg L−1 (1,4-naphthoquinone) to 1.70 μg L−1(9,10-phenanthrenequinone). Relative recoveries ranged from 59.1% (benzo[a]pyrene) to 110% (chrysene) for most PAHs and 68.9% (2-nitrofluorene) to 124% (1-methyl-6-nitronaphthalene) for the nitro-PAHs. The recoveries for quinones ranged from 65.3% (9,10-phenanthrenequinone) to 95.3% (9,10-anthraquinone). The enrichment factor varied from 213 (Nap) to 497 (Flu), from 39 (1,4-naphthoquinone) to 254 (9,10-anthraquinone), and from 122 (2-nitrobiphenyl) to 295 (1-methyl-4-nitronaphthalene) for the PAHs, nitro-PAHs, and quinones, respectively. After validation, the procedure was successfully applied toward the determination of PACs in river and marine water samples. Low-molecular-weight PAHs were detected with high frequencies (62.5–100%) and the total PAH concentration ranged from 2.30 ng L−1 (benzo[a]pyrene) to 1070 ng L−1 (pyrene). Quinones were found at concentrations ranging from below the LOD to up to 19.8 μg L−1. The proposed procedure was thus found to be comprehensive, precise, accurate, and suitable for determination of PACs in water samples. Image 1 • A dispersive micro-solid phase extraction procedure is devised. • A custom-made glass device and C 18 as the sorbent are used. • Organic pollutants in aqueous samples are detected. • Low limits of detection and high enrichment factors are obtained for the analytes. • PAHs and oxygenated PAHs such as quinones are detected at the ng L−1 level. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) without surface capping agents are easily aggregated owing to their high surface energy, leading to an unexpected decrease of their catalytic activity. Herein, we report gold nanoparticles decorated covalent organic framework (COF) as mimetic peroxidase for colorimetric detection of mercury. 1,3,5-Tris-(4-formyl-phenyl)triazine (PT) and 4, 4′-azodianiline (Azo) was employed as the monomers to prepare a novel imine based COF PTAzo under solvothermal conditions. AuNPs are further decorated into the PTAzo to form COF-AuNPs hybrid via a citrate reducing method. The COF-AuNPs show high stability, and exhibits enhanced peroxidase mimetic activity in the presence of Hg2+. The Hg2+ concentration dependent peroxidase mimetic activity of COF-AuNPs enables the development of a sensitive and selective method for detection of Hg2+ in aqueous solution. The developed method gives good linearity in the range of 5–300 nM with the limit of detection of 0.75 nM. The results show that Hg2+-enhanced peroxidase mimetic activity of COF-AuNPs offers great potential for the detection of Hg2+ in real samples. A novel imine based covalent organic framework and gold nanoparticle composite COF-AuNPs was fabricated as stable mimetic peroxidase for sensitive and selective colorimetric detection of mercury. Image 1 • A novel composite COF-AuNPs was fabricated. • COF-AuNPs show high stability as mimetic peroxidase in the presence of Hg2+. • A sensitive and selective method was developed for the determination of Hg2+. [ABSTRACT FROM AUTHOR]

The pre-concentration of major constituents is crucial to accurate and precise determination of trace metals in water samples by inductively coupled plasma mass spectrometry (ICP-MS). In this work, NOBIAS chelate resins were used in the sample concentration for both HPLC and ICP-MS detection. 4-(2-Pyridylazo) resorcinol (PAR) was selected as a precolumn chelating reagent for this research. 520 nm wavelength was used as to minimize the peak of PAR and to reduce baseline noise for HPLC analysis. The sample pre-treatment step was achieved by enrichment and Cd(II), Co(II), Cu(II), Mn(II), Ni(IV), Pb(II), and Zn(II) were detected in the bottled water and tap water samples. The results of two detection methods of ICP-MS and HPLC were compared. Results showed that by acquiring 50-time pre-concentrates of test samples using 250 mg of the Nobias-chelate PA1 chelating resin, the metal contents could be accurately detected using both ICP-MS and HPLC. And the approach of HPLC enables the quantitative detection of bottled water and tap water at different concentrations with determination coefficient (R2) greater than 0.9990. This simple and cost-effective quantitative detection approach using NOBIAS chelate resins and HPLC may widen the application of NOBIAS chelate resins for quantitative detection of more water samples. A chelate resin was used for the enrichment of Cd(II), Co(II), Cu(II), Mn(II), Ni(IV), Pb(II), and Zn(II) in the bottled water and tap water samples. Image 1 • A chelate resin was used for in the enrichment of metal ions in waters. • 4-(2-Pyridylazo) resorcinol (PAR) was selected as a post column chelating reagent in this research. • High performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS) were used for the analysis. [ABSTRACT FROM AUTHOR]

A 3D printed solid-phase extraction (SPE) device for uranium(VI) extraction has been fabricated using stereolithographic 3D printing. The 3D printed device is shaped as a stirred reactor chamber containing a network of small cubes, which were impregnated with TEVA resin for the extraction of U(VI) from water matrices without doing any previous pretreatment. A flow-through system was combined with off-line ICP-MS detection for the accurate and rapid determination of U(VI) at trace levels. The automatic system was satisfactorily optimized using experimental design, obtaining 0.03 and 0.09 ng U(VI) of detection and quantification limits, respectively, and a durability of 11 consecutive extractions. The reliability of the proposed system was confirmed through the analysis of a reference water material (CSN/CIEMAT 2011), and to water samples (tap, mineral and groundwater) by addition/recovery assays obtaining recoveries between 95 and 106%. This study present for the first time the design of a 3D printing SPE device impregnated with TEVA resin for the on-line extraction of U(VI), showing that 3D printing is a powerful tool for simplifying the construction of complex experimental devices and its operation in analytical procedures for pretreatment applications in water matrices. Image 1 • 3D printed SPE device coated with TEVA resin allows the on-line uranium extraction. • Integration of a 3D printed device in a flow system allows the automatic and safety radioactive samples analysis. • Water matrices were analyzed without any pretreatment. [ABSTRACT FROM AUTHOR]

Two kinds of carbon dots (CDs) with different solubility, aqueous soluble CDs (ACDs) and organic soluble CDs (OCDs), were produced at the same time by one step hydrothermal synthesis method using sorbic acid and proline as carbon precursor and nitrogen dopant, respectively. The synthesized CDs were characterized by means of UV, fluorescence, TEM, elemental analysis, IR and XPS et al. Based on the effective and proportional fluorescence quenching by Cr(VI), ACDs were successfully used as a high sensitive and selective probe for Cr(VI) detection. Internal filtration effect (IFE) played an important role in the quenching process. Under the optimal conditions, linear response for Cr(Ⅵ) was observed in the range of 0.5–100 μmol/L, and the calculated detection limit was 34 nmol/L. The method has been satisfactorily applied to detect Cr(VI) ions in real water samples of our campus. Then, the ACDs were further applied for cell imaging in B16F10 cells. Furthermore, OCDs were well dispersed into PMMA to fabricate OCDs/PMMA composites as fluorescent films. ACDs and OCDs were produced at the same time and their multi-functional applications were explored like Cr(Ⅵ) detection, bioimaging, and OCDs/PMMA films. Image 1 • Two kinds of CDs were simply synthesized by one-step hydrothermal method directly. • The fluorescence of ACDs can be selectively quenched by Cr(VI) and applied to detect Cr(VI) in real water samples. • The ACDs are successfully applied for cell imaging in B16F10 Cells. • The OCDs/PMMA composites have been fabricated as fluorescent films. [ABSTRACT FROM AUTHOR]

A dual-function colorimetric probe (Cz-Cy7) with an electron-donating carbazole tethered at the central position of heptamethine cyanine was designed and synthesized, and the performance on CN− and HClO detection were systematically investigated. With the addition of CN−, Cz-Cy7 exhibited remarkable changes in both UV–vis and fluorescence spectra with a good linear relationship to CN− concentration, and a discernible color change under daylight was observed. The limit of detection for CN− was found to be 9.1 nM in DMF and 0.09 μM in DMF/H 2 O. Meanwhile, Cz-Cy7 exhibited a highly sensitive response to HClO in the presence of other ROS (reactive oxygen species) based on the sensing mechanism of oxidative cleavage of olefinic C = = C bond. The limit of detection for HClO was evaluated to be 14 nM in PBS buffer solution (containing 50% CH 3 CN). More importantly, the probe Cz-Cy7 showed good recovery and analytical precision in real water samples for both CN− and HClO detection, indicating it was feasible and reliable for practical application. Moreover, the test strips loaded with Cz-Cy7 were fabricated and validated to be a portable tool for the efficient detection of CN− and HClO by the naked eye. Image 1 • A dual-function colorimetric probe based on Carbazole-Cyanine dyad was developed for CN− and HClO detection. • The probe exhibited high sensitivity/selectivity and rapid response towards CN− and HClO. • The apparent color changes of the probe solutions with CN− and HClO were naked eyes discernible. • The LOD for CN− and HClO were determined to be 0.09 μM and 14 nM in aqueous media. • The application of the probe was successfully achieved in real water samples and test strips. [ABSTRACT FROM AUTHOR]

Studies have shown that microRNAs affect the development of tumors. In many cases, they can be applied as biomarkers for the diagnosis of cancer; therefore, simple and sensitive analytical methods for detection of miRNAs are necessary. In this study, miR-141, which is used to diagnose several types of cancer, was detected in water and serum samples using a biosensor designed based on streptavidin-coated magnetic beads (SMBs), complementary sequences of miR-141 and PicoGreen as the fluorescent dye. The method is relatively fast and simple. Briefly, in the presence of miR-141, the complementary sequence forms a DNA:RNA double–strand on the surface of SMBs with intercalated PicoGreen. Upon attachment of the PicoGreen, the fluorescence intensity increased significantly (1000-fold). In the absence of a target, only single-stranded DNA (complementary strand of miR-141) existed on the surface of the SMBs. The fluorescence of the PicoGreen was low. The results revealed that the detection limits of the biosensor for miR-141 were 70 and 113.8 nmol L−1 in deionized water and serum samples, respectively. The schematic shows that in the presence of miR-141, a double-stranded structure formed on the surface of magnetic beads and upon attachment of PicoGreen a strong increase in fluorescence intensity is observed. In the absence of miR-141, a weak fluorescence was recorded. Image 1 • miRNAs have an important role in the occurrence, progression and metastasis of cancers. • A fluorescent sensor was developed for detection of miR-141 using streptavidin magnetic beads and PicoGreen. • The Biosensor showed good selectivity towards miR-141. • The detection limits of the biosensor for miR-141 was 113.8 nmol L−1 for serum samples. [ABSTRACT FROM AUTHOR]

It is necessary to develop simple and highly sensitive methods for the detection of hypochlorous acid (HOCl)/hypochlorite (ClO−) to ravel its relationship with disease. In this paper, a novel bio-compatible fluorescent (Z)-8-(hydrazonomethyl)-7-hydroxy-4-methyl-2H-chromen-2-one (probe 1b) based on coumarin was synthesized and used for detecting ClO− in PBS buffer (pH = 7.2, 10 mM, 60% C 2 H 5 OH). Probe 1b showed a remarkable fluorescence change from yellow to blue with the limit of detection as low as 2.4 × 10−9 M−1 when ClO− was added. The coexisted anions, metal ions and reactive oxygen species (•OH, 1O 2 , H 2 O 2 , KO 2) showed any competitiveness towards ClO−. In response to ClO−, the fluorescence emission intensity of probe 1b was obviously enhanced within 20 s. The mechanism was confirmed by the ESI - MS and density functional theory calculations (DFT) to reveal that the coumarin lactone bonds C − O was cleavaged by oxidation of ClO − . What's more, probe 1b could be used in practical water samples and showed well recovery. Additionally, the cell imaging experiment was demonstrated that probe 1b could be effectively exploited to imaging exogenous ClO− in vitro. A new probe 1b was designed and synthesized for highly specific and sensitive detection of ClO− with fast response time in living cells. Image 1 • A novel fluorescent probe 1b based on coumarin was designed and synthesized. • The probe 1b could be used for highly specific and sensitive detection of ClO− with fast response time. • The probe 1b could quantitatively detect ClO− in real environmental water samples. • The probe 1b was successfully applied to monitor ClO− in living cells. • ESI-MS and DFT were further verified that the oxidation reaction between the C O of coumarin lactone and ClO−. [ABSTRACT FROM AUTHOR]

In this study, we developed a new fluorescent probe (CMM) based on coumarin dye and malononitrile, for highly sensitive and selective detection of hypochlorite ion (ClO−). CMM showed a 45-fold fluorescence enhancement at 459 nm in the presence of ClO− and displayed an excellent selectivity over other competing species. The probe featured a fast response time (<15 s), which could be in favor of the real-time detection towards ClO−. Meanwhile, probe CMM could effectively monitor ClO− in physiological pH condition and the detection limit was estimated to be as low as 5.7 nM. Furthermore, its preeminent recognition properties made the successful application for monitoring ClO− in environmental water samples and labeling ClO− in living biological cells. Image 1 • A coumarin-based "turn-on" fluorescent probe for hypochlorite was developed. • The probe detect ClO− with high selectivity and low detection limit. • The probe is able to detect ClO− within 15 s. • The probe is successfully applied to detect ClO− in real water samples and living cells. [ABSTRACT FROM AUTHOR]

In this work, a metal-organic framework (MOF) membrane coated copper wire (CW) was prepared as solid-phase microextraction (SPME) materials for extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples. The MOF based SPME fiber was fabricated by a facile and environment-friendly strategy, where the CW acted as both substrate and the copper ion source for MOF membrane growth. Characterization results confirmed that a uniform and dense HKUST-1 membrane was grown on the smooth surface of pristine CW. The effect of extraction parameters (i.e. extraction temperature, extraction time, desorption temperature, desorption time, and salt concentration) were fully optimized. Due to its large surface areas, the MOF membrane coated CW fiber showed good performance with great repeatability (2.6–14%, n = 5), low limits of detection (LODs, 0.12–9.9 ng L−1) and wide linear range (0.01–10 μ g L−1). Moreover, the proposed method was proven to be highly effective for the determination of trace PAHs levels in real environmental water samples where the recoveries of PAHs were in the range of 80.8–114.1%, demonstrating that the as-prepared HKUST-1 membrane coated CW had great potential application in environmental water analysis. Image 1 • The MOF membrane coating was prepared via an in-situ self-transformation method. • The coating exhibited good thermal stability and long service lifetime for PAHs extraction. • The coating was used for the analysis of trace PAHs in practical water samples successfully. • The proposed method achieved a low LODs, wide linearity and good repeatability. [ABSTRACT FROM AUTHOR]

Continuous magnetic stirring-assisted dispersive liquid-liquid extraction followed by dispersive backextraction as a novel pre-treatment technique for adaptable and milliliter volumes of environmental samples has been developed. The procedure was automated using the technique "Lab-In-Syringe". The void of the automated syringe pump was used as size-adaptable extraction chamber. By a flow channel in the syringe piston, continuous flow through the syringe void was enabled. 1-Octanol was used as an extractant and dispersed by the action of a magnetic stirring bar, which was placed inside the syringe and driven by an external rotating magnetic field. Extract washing and dispersive backextraction in an alkaline aqueous acceptor phase were carried out after the preceding extraction from the acidified water sample. Analyte determination was achieved using multivariate spectrum analysis. The method was applied to determine priority pollutants, mono-nitrophenols, in surface water and enabled to reach limits of detection for o-, m-, p- nitrophenol (λ = 418, 390, 400 nm, respectively) of 0.14, 0.26, and 0.02 μmol L−1 (19.5, 36.2, and 2.8 μg L−1), respectively. Under optimized conditions, relative standard deviations were generally less than 5% and enrichment factors of o-, m-, p- nitrophenol 19, 25, and 21, respectively, were achieved using sample volumes of up to 24 mL. Average recoveries of o-, m-, p- nitrophenol from spiked surface water were 94, 82, and 92%, respectively. The concentration of humic acid was found 6-times reduced with respect to the analyte. In addition, adding spectral background modeling allowed nitrophenol determination with precision adequate for routine analysis. Image 1 • Continuous dispersive liquid-liquid microextraction and backextraction is proposed. • Lab-In-Syringe technique with in-syringe magnetic stirring was used for automation. • Nitrophenols were quantified by multivariate spectral analysis with baseline model. • High analytical performance allowed its application to analysis of water samples. • Extension to other analytes and combination with separation techniques is possible. [ABSTRACT FROM AUTHOR]

In this contribution, low-cost and robust biochar material fabricated from waste peanut shells manifest highly-efficient adsorption capability and was prepared into a solid-phase microextraction fiber coating on the external surface of a stainless-steel wire. It was observed from scanning electron microscopy that, a homogeneity of cavities makes up the external surface of the coating, and Raman signals revealed that it contained graphite structures. Coupled with gas chromatography-mass spectrometry (GC-MS), headspace SPME (HS-SPME) based on the novel fiber was applied for the analysis of six polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Under the selected optimum conditions in both extraction and desorption processes, satisfactory analytical performances were achieved, which included good intra-fiber repeatability (relative standard deviations, RSDs in the range from 6.93% to 10.86%, n = 6) and inter-fiber reproducibility (RSDs from 5.61% to 13.59%, n = 4), together with low limits of detection (LODs, 1.09–2.46 ng L−1) and limits of quantification (LOQs, 3.62–8.20 ng L−1), as well as a satisfactory linear range for the analysis of the target PAHs (10–2000 ng L−1). This established method also showed good reliability in the analysis of target PAHs in river water as well as pond water in the downtown area of Guangzhou, China, as the spiked recoveries were in the range from 81% to 116%. Image 1 • Biochar-based solid-phase microextraction fiber coatings were prepared through a simple carbonization process of readily-accessible peanut shells. • The peanut shell-derived coating material featured high porosity outside and graphite-like structures inside. • The fabricated biochar-based coating possessed higher extraction efficiencies towards PAHs than the commercial PDMS. • Sensitive detection of six PAHs in environmental water samples was achieved using headspace SPME. [ABSTRACT FROM AUTHOR]

According to the molecular properties of non-steroidal anti-inflammatory drugs (NSADs), a new adsorbent for magnetic solid phase extraction (MSPE) was designed and synthesized. Triethyl-(4-vinylbenzyl)aminium chloride and 4-vinylbenzeneboronic acid were utilized as dual functional monomers to copolymerize with divinylbenzene on the surface of pre-modified Fe 3 O 4 nanoparticles. The prepared magnetic adsorbent (Fe 3 O 4 @TCVA) was characterized by elemental analysis, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. Due to the abundant boronic acid, quaternary amine and phenyl groups, the Fe 3 O 4 @TCVA displayed satisfactory extraction performance for target NSADs (diclofenac acid, ibuprofen and mefenamic acid) by means of B-N coordination, anion-exchange, π-π and hydrophobic interactions. Under the optimized conditions, the Fe 3 O 4 @TCVA/MSPE was combined with high-performance liquid chromatography with diode array detection (HPLC-DAD) to sensitively analyze NSADs in water and human urine samples. Results indicated that the limits of detection for water and urine samples were in the ranges of 0.014–0.031 μg/L and 0.029–0.11 μg/L, respectively. The relative standard deviations for the intra-day and inter-day assay variability were below 10%. The applicability of the proposed Fe 3 O 4 @TCVA/MSPE-HPLC-DAD method was demonstrated by the successful extraction and quantification of trace levels of NSADs in real water and human urine samples. Satisfactory spiked recovery and reproducibility were achieved. Image 1 • A new dual functional monomers modified magnetic adsorbent was fabricated. • The Fe 3 O 4 @TCVA/MSPE could extract NSADs by means of multi-interactions. • Extraction conditions were optimized thoroughly. • The practical applicability of Fe 3 O 4 @TCVA/MSPE-HPLC-DAD approach was investigated. [ABSTRACT FROM AUTHOR]

An effective dithiourea-appended 1,8-naphthalimide fluorescent probe was designed and synthesized. This probe could recognize Hg2+ and Ag+ sensitively and selectively in neutral and alkaline conditions. Moreover, the probe detected Hg2+ alone at pH between 2 and 6. The sensing ability of the probe was explored by UV–vis, fluorescence, FTIR and 1H NMR spectroscopy. The probe was quenched by Hg2+ and Ag+ with 1:1 binding ratios in MeCN/H 2 O (4/1, v/v) mixed solution with binding constants of 3.76 × 104 L mol−1 and 2.47 × 104 L mol−1, respectively. The linear concentration ranges for Hg2+ and Ag+ were 0–17 μmol L−1 and 0–24 μmol L−1 with detection limits of 0.83 μmol L−1 and 1.20 μmol L−1, respectively, which allowed for the quantitative determination of Hg2+ and Ag+. The new probe, 3a, was successfully applied to the fluorescence imaging of Hg2+ and Ag+ in HepG2 cells, demonstrating its potential application in biological science. Moreover, 3a was used to measure Hg2+ and Ag+ in tap water, drinking water and ultrapure water samples. The recoveries of Hg2+ and Ag+ in water samples were 96–99% and 98–103%, respectively. Therefore, the proposed method showed promising perspectives for its application, aimed at detecting Hg2+ and Ag+ in fluorescence imaging and real water samples. fx1 • A new dithiourea-appended 1,8-naphthalimide probe for detecting Hg2+ and Ag+ has been developed. • The probe could be used to detect Hg2+ at pH 2 ~ 6 individually. • The probe was evaluated by the determination of spiked Hg2+ and Ag+ in real water samples. • The detection of Hg2+ and Ag+ in liver cancer cells using this probe had been achieved. [ABSTRACT FROM AUTHOR]

Abstract In this study, a new metal-organic framework-monolith composite for in-tube solid phase microextraction phase (IT-SPME) of fluoroquinolones (FQs) was prepared. 4-Vinylbenzoic acid was copolymerized with ethylenedimethacrylate in a fused silica capillary to form porous monolith. After that, zeolitic imidazolate frameworks (ZIF-8) were synthesized in situ within the pores and the surface of the monolith by controlled layer-by-layer self-assembly of Zn2+ and imidazole. The introduction of ZIF-8 enhanced the surface area of monolith composite, and thus, improving the extraction performance of IT-SPME for FQs obviously. Under the optimized conditions, a highly sensitive method for the monitoring of FQs residue in water and honey samples was developed by the on-line combination of IT-SPME with high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The limits of detection (S/N = 3) for the targeted FQs in water and honey samples were as low as 0.14–0.61 ng/L and 0.39–1.1 ng/L, respectively. The relative standard deviations (RSDs) for intra-day and inter-day assay variability were less than 10% in all samples. The established on-line IT-SPME-HPLC-FLD was successfully used to detect ultra-trace FQs in environmental water and honey samples. Recoveries at different spiked concentrations ranged from 80.1% to 119% and 80.2–117% for water and honey samples, respectively, with satisfactory reproducibility. Compared to up-to-date reported methods, the proposed approach exhibits some features such as high sensitivity, convenience, partial automation, low consumptions of sample and solvent. Graphical abstract fx1 Highlights • A novel ZIF-8@monolith composite-based IT-SPME was developed. • The MM-CMC/IT-SPME exhibited satisfactory extraction performance for FQs. • An online MM-CMC/IT-SPME-HPLC-FLD system was proposed. • The method was successfully applied to analyze ultra trace FQs in complex samples. [ABSTRACT FROM AUTHOR]

Abstract Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1–500 μg L–1) with a coefficient of determination (R 2 ) of 0.9959–0.9999, low limits of detection (0.06–0.17 μg L–1) and limits of quantification (0.20–0.56 μg L–1), good analyte recoveries (80–96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature. Graphical abstract fx1 Highlights • MISG was used as sorbent in MMM for SAs microextraction. • The developed method provides high sensitivity of SAs by HPLC-DAD. • Excellent accuracy and precision were achieved. • The method was applied to analysis of water samples. • Superior benefits: simplicity, cost-effective, rapid analysis and inexpensive. [ABSTRACT FROM AUTHOR]

Abstract In this work, for the first time, a revolving solvent bar microextraction (RSBME) system was introduced as an efficient alternative method to conventional SBME. The setup proposed for RSBME provides a stable and repeatable method to increase the preconcentration factor. In order to provide the maximum extraction capacity of the organic acceptor phase, four-hollow fibers were applied. In this setup, an electrical motor driving rotator was employed as mechanical support for the hollow fibers and also to stir the donor phase during extraction time. The applicability of this technique was assessed by preconcentration-determination of ammonia in the environmental water samples. The effective factors on the RSBME efficiency were examined and optimized. Under the optimized RSBME conditions, ammonia was quantified by microcell UV–Vis spectrophotometry, with extensive linearity ranging from 15 to 1000 µg L−1 (R2 = 0.9972), and RSD values less than 3.5%. A preconcentration of 372-fold with the detection limit of 4.5 µg L−1 was achieved. The green character of this technique was evaluated based on the analytical Eco-Scale tool and compared with a reference method. The setup proposed can be applied for the simultaneous extraction of acidic and basic compounds from biological and environmental samples in the near future. Graphical abstract fx1 Highlights • An alternative new method for conventional SBME. • Revolving solvent bar micro-extraction (RSBME) setup with four-hollow fibers geometry. • The extraction system repeatable and stable with high extraction efficiency. • Trace determination of ammonia in the environmental water samples. [ABSTRACT FROM AUTHOR]

Abstract Thiophenol is widely known as a highly toxic substance that can cause serious harm to the environment and health. Rapid and non-destructive detection of thiophenol is of great significance for environmental management. In this work, we designed and synthesized a near-infrared (NIR) fluorescent probe, (E)−4-(2-(4-(dicyanomethylene)−4 H -chromen-2-yl)vinyl)−2-formylphenyl-2,4-dinitrobenzenesulfonate (DCM-CHO-D), that can respond to thiophenol rapidly (less than 3 min) based on intramolecular charge transfer (ICT) mechanism. DCM-CHO-D has high selectivity and sensitivity to the detection of thiophenol. And there is a linear relationship between the fluorescence intensity of DCM-CHO-D and thiophenol concentration in the range of 0–10 μM, the limit of detection (LOD) is as low as 0.22 μM. What′s more, DCM-CHO-D can not only be used as an ideal colorimetric tool for detecting thiophenol in water samples, but also image thiophenol in living cells, indicating its potential utility for thiophenol sensing in environmental and biological samples. Graphical abstract fx1 Highlights • The emission wavelength of the probe is in the near infrared region. • The obvious change in color could be used for "naked-eye" detection. • The response time of the probe to thiophenol is as low as 3 min. • The probe could be applied for thiophenol detection in real water samples and living cells. [ABSTRACT FROM AUTHOR]

Abstract A modulation approach with 4-hydroxybenzhydrazide as the modulating agent was designed for constructing 2,4,6-triphenoxy-1,3,5-benzene-based covalent organic frameworks (COFs). The COFs materials were employed as solid phase microextraction (SPME) coatings for the extraction of phthalate esters (PAEs). Various experimental conditions including extraction temperature, extraction time, salt concentration, and desorption time were investigated and optimized. The introduction of modulating agent into the synthesis of fibers significantly enhanced the extraction efficiency towards PAEs. The linear range was 1–100 μg L‒1 and the detection limits in the range of 0.032–0.451 μg L‒1 were achieved with good linearity ranged from 0.9904 to 0.9970. Inter-batch and intra-batch relative standard deviations were in the ranges of 0.83–4.67% and 3.08–9.73%, respectively. Moreover, the developed coating fibers were used for the extraction of PAEs in water samples and satisfactory recoveries were achieved. Graphical abstract The OH-TPB-COFs coated SPME fibers were prepared for the preconcentration of PAEs in water samples coupled with GC-FID. fx1 Highlights • The modulating agent was designed for constructing covalent organic frameworks. • The prepared OH-TPB-COF was employed as SPME coating. • The modulating agent can significantly enhanced enrichment ability of the fiber. [ABSTRACT FROM AUTHOR]

Abstract Increasing use of TiO 2 nanoparticles (NPs) leads to an accumulation in environment and a risk to human. In this work, an on-line monolithic capillary microextraction (CME)-inductively coupled plasma mass spectrometry (ICP-MS) method was developed for sensitive determination of TiO 2 NPs in environmental water samples. With the presence of citric acid, TiO 2 NPs can be selectively adsorbed on the poly(acrylamide)-vinylpyridine-methylene bis-(acrylamide) (poly(AA-VP-Bis)) monolithic column at pH 1, whereas Ti ions cannot be adsorbed. Factors affecting the extraction efficiency such as sample pH, concentration of citric acid and elution conditions were carefully investigated. Under the optimum conditions, a detection limit of 0.63 μg L−1 for TiO 2 NPs and a sample throughput of 6 h−1 were achieved. The method can be applied to the determination of TiO 2 NPs in the size range of 5–100 nm. The developed method was then applied to the analysis of TiO 2 NPs in the East Lake water and Yangtze River water, and recoveries of 84–109% were obtained for spiked samples. Compared with other reported methods for the determination of metal oxide NPs, the developed on-line monolithic CME-ICP-MS has the merits of simple operation, high throughput and no need for digestion before ICP-MS detection. Graphical abstract fx1 Highlights • An on-line monolithic CME-ICP-MS method was developed for sensitive analysis of TiO 2 NPs in water. • TiO 2 NPs of 5–100 nm can be extracted and distinguished from Ti ions with the presence of citric acid. • The method is simple, high throughput and no digestion required before ICP-MS detection. [ABSTRACT FROM AUTHOR]