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Endocrine disrupting chemicals such as natural and synthetic steroid hormones and bisphenols are among the most important pollutants in the aquatic environment. We performed an environmental chemical analysis of five Slovenian water samples, two rivers, one groundwater, and the influent and effluent of wastewater treatment plants, with a highly sensitive analysis of twenty-five endocrine-disrupting compounds belonging to the groups of natural hormones, synthetic hormones, and bisphenols. Since these compounds are simultaneously present in the environment, it is important to study their individual effects as well as the effects of mixtures. We investigated in vitro the estrogenic potency of selected natural and synthetic steroid hormones and bisphenols detected in surface, ground and waste water in Slovenia using the OECD-validated transactivation assay on the cell line Hela9903. We predicted their mixture effects using the concentration addition model and compared them with experimentally determined values. Two mixing designs were used: a balanced design in which chemicals were combined in proportion to their individual EC$_{50}$ values, and an unbalanced design with compounds in proportion to their measured concentrations in the environmental samples. The estrogenic effects of the experimental mixtures followed the concentration addition model. Real water samples exhibited weaker estrogenic effects, showing the great heterogeneity of the real water samples.

Algae-associated clinical infections and the presence of algae and cyanobacteria as building contaminants are less understood than those of analogous bacteria and fungi. As algae and their affiliated complications have been further recognized, it has become evident that these organisms are emerging pathogens. Algae and the closely related cyanobacteria have been documented to cause a variety of infections and intoxications in humans and dogs. These organisms can be present in a wide array of water-damaged buildings (especially related to environmental water reservoirs) and building materials. Algae may also be despoilers, destroyers, or defacers.

A powerful analytical method based on microwave plasma torch/mass spectrometry (MPT-MS) was developed to rapidly detect mental elements in environmental water from Poyang lake in China. With minimum or uncomplicated sample manipulation, raw water samples were ionized by MPT for subsequent LTQ-MS analysis under negative ion mode. Typical potential contamination sources such (e.g., iron, cobalt, and nickel) were detected and identified by collision-induced dissociated (CID) experiment. It was found that the three metallic elements were formed as [M(NOx)mOn]−, which was universal; thus, they could be target ions. For the given elements, their limits of detection (LOD) were assessed as 0.09 μg•L−1 for iron ion, 0.03 μg•L−1 for cobalt ion, and 0.33 μg.L−1 for nickel ion under the optimized conditions; good determination coefficient (R2 ≥ 0.99) and the relative standard deviation (RSD, 2.0–11%, n = 11) were obtained. For current actual samples under testing, short analysis time for a single sample (less than 1 min), the average levels for iron, cobalt, and nickel, reached allowable concentrations of national standards, which also suggested this method is practically effective and usable. Moreover, possible ionization mechanism of metallic elements in MPT source was also discussed in this work, which may provide insight and useful information for the metal organics derived from water environment or metabonomics by MPT-MS. On the whole, this study lays a solid basis for the in-site mass spectrometry analysis of aqueous samples in relevant fields.

Background Enteric caliciviruses, including noroviruses (NoVs) and sapoviruses (SaVs) are the most significant pathogens associated with waterborne and foodborne outbreaks of nonbacterial acute gastroenteritis in humans worldwide. Methods In this study, 126 environmental water samples collected from 6 different sources in Chiang Mai, Thailand from November 2016 to July 2018 were examined for the presence of genogroups I, II, IV (GI, GII, GIV) NoVs and SaVs by using RT-nested PCR assays, genome sequencing, and phylogenetic analysis, Results Forty out of 126 (31.7%) water samples were positive for one or more caliciviruses throughout the years of study with high prevalence in winter. Among 126 tested specimens, 34 (27.0%), 30 (23.8%), 3 (2.4%), and 2 (1.6%) were positive for NoV GI, GII, GIV, and SaV, respectively. For NoV GI, 6 different genotypes were identified with the most predominant of GI.1 genotype (17 strains). In addition, 6 different genotypes of GII were detected with high prevalence of GII.17 (12 strains) and GII.2 (11 strains). It was interesting to note that our study reported the detection of NoV GIV for the first time in water samples in Thailand, and all were GIV.1 genotype. For SaV detection, only 2 water samples were positive for SaV GI. Conclusions The data revealed heterogeneity and highly dynamic distribution of NoV GI, GII, GIV, and SaV in environmental water in Chiang Mai, Thailand, during the study period of 2016–2018.

A signal-amplified mercury sensing biosensor with desired sensitivity was developed through firstly using the GFP mutant with fluorescence increasing response towards Hg2+ as the reporter module. The developed biosensor showed response for Hg2+ in a relatively wide range of 1–10,000 nmol/L, and the detection limit was improved one or two orders of magnitude in comparison with most metal-sensing biosensors in similar constructs. In addition, the biosensor could distinguish Hg2+ easily from multiple metal ions and displayed strong adaptability to extensive pH conditions (pH 4.0–10.0). More importantly, the developed biosensor was able to provide an initial assessment of Hg2+ spiked in the environmental water with the recoveries between 85.70% and 112.50%. The signal-amplified strategy performed by the modified reporter module will be widely applicable to many other whole-cell biosensors, meeting the practical requirements with sufficient sensing performance.

2,4,6-trinitrotoluene (TNT) sensing on surfaces and in solution is an important issue in sensor fabrication for homeland security and environmental protection. Herein, Play-Doh, a modeling material popular for kids, was proposed as a versatile sensor for on-site fluorescent (FL), visual FL (VFL), and colorimetric detection of TNT both on surfaces and in solution after being doped with -NH2 through a one-step approach. Play-Doh exhibits FL emission due to the main ingredient of flour. After -NH2 doping, amino-Play-Doh (APD) was utilized to construct a FL sensor based on FL resonance energy transfer and inner filter effect for TNT detection. The advantage of APD was that no additional fluorophore was needed compared with the traditional sensors for FL and VFL analysis. The orange complex visible to the naked eye was also recorded for smartphone-based colorimetric detection of TNT. In both cases, the APD demonstrated good analytical performance for TNT. Finally, APD was successfully utilized for TNT sensing on fingerprints, luggage, and in environmental water samples, respectively. Play-Doh might be a potential sensor for future on-site detection of TNT owing to the merits of being cost-effective and versatile.

Because of the high diversity of enteric viruses in the environment, there is an increasing need for methods enabling the multiple detection of different pathogens. Quantitative, emerging digital polymerase chain reaction (PCR) and isothermal amplification approaches are capable of quantification of multiple targets and hence are suitable for long-term monitoring and source tracking of enteric viruses in the aquatic environment. The combination of culturing with PCR-based detection enables rapid viral risk assessment, especially with host tissues capable of propagation of several viral strains. Viability assays may provide a better understanding on viral survival than PCR-based approaches alone; however, the usefulness of these assays in waste water and environmental water samples should be further investigated. Undoubtedly, emerging sequencing-based technologies provide invaluable data on the ecology and diversity of viruses and along with rapid on-site technologies, for example, biosensors, may be implemented in viral risk assessment in the aquatic environment in the near future.

A new oligothiophene derivative (3TY) was synthesized, and used as a highly selective hydrazine (N2H4) chemosensor in ∼100% aqueous solution with “naked-eye” colorimetric and “turn-on” fluorimetric response. This chemosensor 3TY enabled ultrafast and ultrasensitive detection of hydrazine with ultralow detection limit of 1.45 nM (0.04 ppb) in a wide sensing pH range from 6 to 10. The sensing mechanism of 3TY toward hydrazine was strongly and fully confirmed. More importantly, colorimetric paper test strip and solid support silica are easily prepared by 3TY for on-site and real-time detection of hydrazine. Furthermore, 3TY displays many potential applications for detecting N2H4 in environmental water and human urine along with bio-imaging in living HeLa cells.

The quantification of pathogens is important for assessing water safety and preventing disease outbreaks. Culture-independent approaches, such as quantitative PCR (qPCR) and digital PCR (dPCR), are useful techniques for quantifying pathogens in water samples. However, since pathogens are usually present at low concentrations in water, it is necessary to concentrate microbial cells before extracting their DNA. Many existing microbial concentration methods are inefficient or take a long time to perform. In this study, we applied a coagulation and foam separation method to concentrate environmental water samples of between 1000 and 5000 mL to 100 μL of DNA (i.e., a 1–5 × 104-fold concentration). The concentration process took

Mercury pollution has always been a huge threat to human health due to its significant toxicity. Thus, it's the continuing goal to obtain new mercury detection techniques that are cost-effective, operational stable, performance efficient, and applicable to the environmental and biological milieus. In this research, the soluble pigment pyocyanin with anti-bacterial and anti-fungal activities, the biosynthesis pathway of which was engineered under the regulation of Hg2+-dependent transcriptional activator MerR, was firstly used as the visual detection signal in the whole-cell biosensor. The engineered biosensor displayed optical sensing window and a good linearity for Hg2+ in the range of 25–1000 nM, and the detection limit could reach as low as 10 nM. It permitted on-site detection of bioavailable Hg2+ with extraordinary selectivity and could resist the interferences of extra metal ions. What's more, the developed biosensor performed function well in a wide pH range (pH 4–10) as well as the environmental water. By fully imitating and utilizing the biosystems from nature, the engineered colorimetric biosensor has great economic and performance advantages over most chemosensors as well as whole-cell biosensors in the practical application of detecting Hg2+ in the contaminated aquatic systems.

Thiophenols as high toxic environmental pollutants are poisonous for animals and aquatic organisms. Therefore, it is indispensable to monitor thiophenols in the environment. Herein, a novel near-infrared fluorescent probe was developed for the detection of thiophenols, which was easily prepared by one-step coupling of 2,4-dinitrobenzenesulfonyl chloride with Nile blue. The probe showed a significant near infrared (∼675 nm) fluorescence “turn-on” response to thiophenols with some good features including chromogenic reaction, high sensitivity and selectivity, fast response, near-infrared emission along with low detection limit (1.8 nM). The probe was employed to rapidly and visually determine thiophenols in several industrial wastewaters with good recoveries (90–110%). Moreover, this probe has been demonstrated good capability for imaging thiophenol in HeLa cells.

A novel colorimetric and fluorometric dual-channel sensor DA with a favorable optical property and high specificity via a facile synthesis for Cu 2+ was developed. DA showed a remarkably rapid response and high selectivity for Cu 2+ over other metal ions with low detection limit of 15.1 nM. The sensing mechanism of DA for Cu 2+ was based on the chelation-enhanced fluorescence quenching (CHEQ) mechanism, and further confirmed by optical measurements, FTIR, HRMS and DFT calculations. Importantly, DA for sensing Cu 2+ possessed excellent sensing performances including colorimetric and fluorometric dual-mode detection, fast response, good reversibility, wide pH response range and strong anti-interference ability. Moreover, the DA could be not only applied to quantitatively detect Cu 2+ in environmental water, food and drink samples, but also show highly colorimetric detection of Cu 2+ on test strips and silica, indicating its possibility to be utilized as a convenient and low-cost sensor for environment and food monitoring.

This work introduces a method for rapid isolation of target bacterial cells using “bacteria-sized,” gold-coated magnetic microdiscs (1.5 μm in diameter, 80 nm in thickness). These microdiscs are functionalized with DNA aptamers for selectively isolating Escherichia coli cells from lab-prepared and environmental water samples at concentrations as low as 102 CFU/100 mL with no enrichment. This microdisc platform enables viability assay on the magnetically captured discs using fluorescent markers such as SYTO9, propidium iodide, and carbon quantum dots, providing both a detection and viability step in a single analysis. The significance of this gravity-driven separation technique is the ability to rapidly isolate target cells from relatively large sample volumes (up to 100 mL) with simple field-deployable apparatus in one step, without the use of complicated equipment or energy. This technique has immediate application for rapid (

A simple and rapid fluorescence “on-off-on” approach for sensing Hg2+ and paraquat was designed by using nitrogen doped graphene quantum dots (N-GQDs) and N-GQDs/Hg2+ system, respectively. It was found that the fluorescence of N-GQDs solution was quenched in the presence of Hg2+ ions (turn off), and the quenched N-GQDs/Hg2+ system was recovered after addition of paraquat (turn on), due to the higher affinity of paraquat and Hg2+ than that of N-GQDs and Hg2+ that resulting into the release of Hg2+ from the surface of N-GQDs and the fluorescence recovery of N-GQDs. The developed fluorescence “on-off-on” approach exhibited high selectivity and sensitivity for detection of Hg2+ and paraquat. Under the optimum experimental conditions, good linearities were achieved over the range of 0–4.31 μM for Hg2+ and 0.05–2.0 μg mL−1 for paraquat, respectively. The detection limits for Hg2+ and paraquat were 23 nM and 19 μg L−1, respectively, and the recoveries of Hg2+ and paraquat spiked in real samples ranged from 95% to 105.8%. Results of this study suggested that the highly selective and sensitive fluorescence “on-off-on” approach can be used to the detection of Hg2+ and paraquat in real environmental water samples.

Silver is one of the most important heavy metals with a broad range of applications; however, it can have significant negative impacts on both the ambient environment and organisms. For this work, an interesting fluorescence polarization sensor based on SH-DNA functionalized gold nanoparticles (AuNPs) was proposed for the detection of Ag+ in aqueous solutions. Moreover, this sensing strategy is quite simple, sensitive, selective, and cost-effective. Ag+ ions can interact specifically with a cytosine–cytosine (C–C) mismatch in DNA duplexes to form stable metal-mediated cytosine–Ag+–cytosine (C–Ag+–C) base pairs. The creation of these C–Ag+–C complexes results in evident changes in the molecular volume and fluorescence polarization signal. The stable hybridization between the two probes occurs with the formation of the C–Ag+–C complex in the presence of Ag+ ions, which leads to obvious fluorescence quenching in contrast to the system without AuNP. This assay may be employed to identify nanomolar levels of Ag+ within 6 min at room temperature. Furthermore, the sensor was successfully adopted to detect Ag+ ions in environmental water samples, which may facilitate the potential development of a range of environmental monitoring applications.

In this study, we synthesized a novel fluorescent probe (S-TC) based on Thiooxo-Rhodamine B. In the design of the probe, we sulfided carbonyl groups of rhodamine spironolactam to thiocarbonyl groups. C S functional group was used as a recognition group for Hg2+. S-TC has a good spectral response to Hg2+ in the EtOH/H2O solution (1:1, v/v) with low detection limits and high binding constants. The detection limit and the association constant was calculated as 0.077 μM and 1.70 × 104 M−1, respectively. S-TC displayed the traditional reversible “turn-off-on” fluorescence change with 1:1 binding stoichiometry. It is feasible to detect Hg2+ in real environmental water by S-TC. Biological experiments demonstrated that S-TC can be used to detect to Hg2+ in living cells, animals and plant tissues.

A Fe3+-specific probe (N-TC) based on Rhodamine B was designed and synthesized. N-TC has a good spectral response to Fe3+ in the EtOH/H2O solution (1:1, v/v, HEPES, 0.5 mM, pH = 7.38) with low detection limits and high binding constants. N-TC displays the reversible “turn-off-on” fluorescence response with 1:1 binding stoichiometry. It is further proven to be practical in sensitively monitoring trace Fe3+ in environmental water specimens. Biological experiments demonstrated that N-TC can be respectively used as a probe for detection of Fe3+ in living cells, animals and plant tissues.

Hydrazine, as a strong reducing agent, has been extensively used in many industrial manufactures. However, it is a potential human carcinogen and an environmental contaminant due to its high toxicity. Therefore, developing an ultrasensitive method for determining hydrazine in real water and biosystems is of great significance. Herein, based on coumarin dye, a turn-on fluorescent probe Cou-1-N2H4, which contains an acetyl group as the trigger unit and the fluorescence quencher, is developed. The probe can achieve a rapid (3min) and colorimetric sensing detection for hydrazine with an extremely low limit detection (11.9 nM or 0.38 ppb). More importantly, the practical utilities of probe have been successfully proved through quantitative N2H4 detection in environmental water samples and bioimaging of N2H4 in living cells.

However the usage of insecticides are essential to safeguard the crops, the increase in its permissible levels imposes several health issues. The organophosphate insecticides like fenitrothion (FNT) are known for its rapid migration properties and adverse health effects. Therefore, precisely detecting the dissemination of FNT in ecology is very much essential. In this article, we reported a synthetic approach to rGO-Tungsten carbide nano-polyhedrons (rGO-WC NPHs) composite. Then economically, rGO-WC NPHs were fabricated on the screen-printed carbon electrode (SPCE) for the determination of FNT in environmental water and forest soil samples. As expected its shows moral analytical parameters, such as wider linear range of 10 nM–471.2 μM, with the very low detection limit of 1.15 nM. The sensitivity possessed by the prepared robust FNT detector is 5.3760 μAμM−1cm−2. The results acquired for the developed sensor (rGO-WC NPHs/SPCE) were also compared with the standardized HPLC method to validate the robustness of the sensor.

In this work, we report a chemiluminescent (CL) design for the quantitative sensing of para-phenylenediamine (PPD) at sub-μM levels. Experiments determined that PPD accelerates the diazotization of luminol to luminol-diazodium in contrast with its isomers and analogues including o-phenylenediamine, m-phenylenediamine, phenylamine, and m-aminophenol. Based on this finding, a highly selective CL method for sensing trace PPD over its isomers and analogues was first established by measuring the luminol-diazodium yielding enhanced CL. After optimizing all device parameters and experimental variables, a flow sensing manifold with on-line luminol diazotization was investigated. Experiments demonstrated a sensitive CL response to PPD concentrations in the range of 0.30˜3.0μM and 3.0˜10.0μM, with a limit of detection (3σ) of 0.05μM. Our CL sensing method was applied to PPD detection in environmental water samples and hair dyes in good agreement with GC–MS method. The mechanism of PPD-responsive CL was studied and was suggested to involve the conversion of PPD-diazonium to luminol-diazodium, which increases the yield rate of luminol-diazonium, resulting in remarkably enhanced CL.

Magnetic nanoparticles (MNPs) have already proven their efficacy in the disposal of a wide array of environmental contaminants in recent years. However, the difficulties in dispersibility and agglomeration of MNPs arising from its own physical and chemical properties limit its large-scale application. Herein, we fabricated the carbon dots/fatty acid-coated MNPs (CDs/C11-Fe3O4) through a facile and simple method. To utilize the advantage of carbon dots, these limitations can be mitigated by diminishing the size of MNPs and modifying the surface of MNPs. Detailed characterization including VSM, FT-IR, XPS and TEM conformed that the higher adsorption capacity of CDs/C11-Fe3O4 is mainly attributed to low average size (

We demonstrate here a sustainable approach to generate carbon-quantum dot (CQD) using denatured (spoiled) milk by a simple one-step hydrothermal method. The unique photophysical property of the CQD has resulted in selective sensing of the chromium ions (Cr6+) as low as 14 µM in control and environmental water samples. The CQD electrode delivered a specific capacitance of 95 F g−1 with an exceptional stability over 1000 cycles.

A novel dual-excitation fluorescent probe, Tb3+-dtpa-bis(fluorescein), for detecting hydrazine is designed based on the special emissions of Tb3+-dtpa-BHz and fluorescein at 515 nm and 520 nm, respectively, under 247 nm and 480 nm excitation wavelength lights. The affecting factors including hydrazine concentration, solution pH value and interfering substances on the detection of hydrazine are examined. The high sensitivity and high specificity of Tb3+-dtpa-bis(fluorescein) in hydrazine detection could be confirmed. Two good linear responses of fluorescence emission intensities of Tb3+-dtpa-bis(fluorescein) at 515 nm and 520 nm as functions of hydrazine concentration in range of 3.00 × 10−5 mol L−1 - 4.50 × 10−5 mol L−1 are obtained, respectively. The LOD of 13 ppb (4.08 × 10−7 mol L−1) for 247 nm wavelength light excitation and 8 ppb (2.50 × 10−7 mol L−1) for 480 nm wavelength light excitation are achieved, which are close to and lower than TLV (10 ppb) of the EPA, respectively. The theoretical calculations on HOMO-LUMO energy levels and the interfacial plots of the molecular orbitals for probe and its final product based on density functional theory (DFT) are performed. In addition, the detections of hydrazine in real water samples and living cells are also studied. The experimental results indicated that the developed fluorescent probe could be applied for the determination of hydrazine in environmental water samples and living cells.

Ratiometric fluorescence sensing based on intrinsic dual-emitting nanomaterials is very intriguing for their simplicity and efficacy. However, intrinsic dual-emitting gold nanocluster-based fluorescence ratiometry remains unexplored. In this work, a ratiometric fluorescence assay for detection of mercuric ions (Hg2+) has been developed using sole intrinsic dual-emitting gold nanoclusters (DE-AuNCs). The DE-AuNCs, simply synthesized by reducing chloroauric acid with an appropriate amount of glutathione, had two distinct intrinsic emission bands peaked at 610 nm and 810 nm respectively. When exposed to Hg2+, the 610 nm emission of the DE-AuNCs was remarkably quenched serving as a reporter signal, while the 810 nm emission almost kept unchanged serving as a reference signal, and thus giving a ratiometric signal. This ratiometric method showed high sensitivity and selectivity for sensing Hg2+ with low LOD down to 0.19 ppb which is quite lower than the WHO drinking-water guideline for inorganic mercury, and was successfully applied to the detection of Hg2+ in environmental water samples.

Design and fabrication of cost effective analytical tools to monitor toxic organic emissions in eco system is of a great necessity. Nitrophenols are a class of widespread toxic organic pollutant lead to serious adverse effects in biosphere on its consumption. This article reports a high sensitive, cost effective, robust electrochemical sensor for 4-nitrophenol (4-NP) in environmental water samples. A novel sheet like CoMnO3 (CMO Ns) nanocatalyst was synthesized via oxalic acid assisted co-precipitation technique and employed as electrocatalyst for the high sensitive detection of 4-NP. The physiochemical properties of CMO Ns are studied in detail via XRD, FTIR, TEM, TGA, and XPS. TEM results reviled the protocol is an excellent way for synthesis of a uniformly distributed CMO Ns with lathery surface. Evident to the surface and other physiochemical studies the CMO Ns based sensor holds superior electrocatalytic activity towards 4-NP detection with excellent sensitivity (2.458 μA μM−1 cm-2) coupled with nanomolar detection (10 nm) limits. Moreover, the constructed sensor holds reliable long-term durability, good reproducibility, and excellent working stability. The practical applicability of the developed sensor was evaluated by determination of 4-NP in samples acquired from water resources with RSD ± 3.3%.

A rapid and efficient method for extraction of 12 phenoxy carboxylic acids (PCAs) in environmental water samples was established based on metal–organic framework MIL-101 assisted dispersive solid phase extraction (DSPE). 12 PCAs were labeled by d0-10-methyl-2-(piperazin-1-ylsulfonyl)anthracen-9(10H)-one(d0-MASPz) and d3-10-methyl-2-(piperazin-1-ylsulfonyl)anthracen-9(10H)-one(d3-MASPz), allowing each analyte to have an isotope internal standard. A stable isotope-coded strategy for the detection of 12 PCAs was developed under optimized extraction conditions and UHPLC-MS/MS conditions. All PCAs analytes were in good linearity in the concentration range of 5–1000 ng/L, and the calibration function was verified by the Mandel fitting test with a 95% confidence level. The LODs and LOQs were estimated by the IUPAC's recommendations. The LODs ranged from 0.18 to 0.88 ng/L, and LOQs ranged from 0.59 to 2.90 ng/L. The intra-day and inter-day precision in three spiked levels (5, 50 and 100 ng/L) were in the range of (1.40 ± 0.14) %– (2.76 ± 0.12) % and (2.60 ± 0.26) %– (3.83 ± 0.32) %, respectively. The developed method has been successfully applied to the determination of PCAs in environmental water samples with recoveries ranging from 95.3% to 105.5%. All of the precision and recovery analyses were done in triplicate.

Mercury ions and silver ions will be doped in environment during the entire process of water circulation, which is harmful to ecological balance and human body. Surface Enhanced Raman scattering (SERS) acts as an effective method in detecting heavy metal ions, due to its easy processing, rapid detection, and fingerprint identification. At present, it is still a challenge to simultaneously detect multiple heavy metal ions based on SERS sensor. Herein, we developed a new SERS aptasensor, applying cascade nucleic acid amplification strategy to detect Hg2+ and Ag+, which greatly improved the sensitivity. Meanwhile, the use of aptamers can transform the concentrations of Hg2+ and Ag+ into DNA signal. And thymine-Hg2+-thymine and cytosine-Ag+-cytosine pairs were formed to simultaneously identify Hg2+ and Ag+. Multiple analytical strategy of this SERS aptasensor can not only avoid the inconvenience caused by different techniques or experiment conditions, but also reduce cost, time, and difficulty. In consequence, we obtained a lower detection limitation (LOD Hg2+=4.40 aM, LOD Ag+=9.97 aM) in the linear range of 0.2-125 fM. The results demonstrate that this SERS aptasensor is capable of being widely applied to simultaneously detect multiple heavy metal ions or other toxic substance in environmental water.

A novel ultraviolet (UV) atomization atomic fluorescence spectrometry (UV-AFS) without chromatographic separation was developed for quantitative speciation analysis of mercury (inorganic mercury (Hg2+) and methylmercury (MeHg+)) in food samples. In the proposed method, with 0.1% (m/v) KBH4 used as a reductant, inorganic mercury was measured by using the non-ultraviolet radiation mode. However, under the ultraviolet atomization, the volatile MeHg+ hydride (MeHgH) generated by KBH4 can be transformed to elemental mercury vapor, and total Hg (MeHg and Hg2+) was detected in this UV atomization mode. Under the optimized experimental conditions, the limits of detection (LODs) were found to be 0.015 and 0.081 mg L−1, for Hg2+ and MeHg+. And the relative standard deviations (RSDs) (n = 11) were 2.4% and 0.4%, respectively. Spiked environmental water samples including seafood, fruits and vegetables were determined and satisfactory recoveries were obtained for MeHg+ and Hg2+ detection.

Low-priced bacterial sensors for testing different water contamination have the potential to save millions of lives. The present study reports a membrane-based kit (strip) that comprises tetrazolium dye and a carbon source for the detection of live bacteria in any kind of water source. Color change is observed on the strip when dipped into water containing bacteria that allows visual detection of contamination without the need of any expensive instruments. The strip efficiently estimated different concentrations of E. coli in the water on the basis of time taken to change the color. The results thus obtained supported that membrane-based strip could quantify live bacteria present in a variety of water samples. The kit also successfully worked in various environmental water samples (pond, sea, ground and municipal water) which may improve its acceptability by different end users such as in aquaculture industry, swimming pool and domestic/municipal water etc. These strips exhibit a feasible manufacturing approach for low-cost bacterial detection in majority of water sources.

Salivirus (SalV), also known as klassevirus, is a newly discovered member of the Picornaviridae family, which has been proposed to be a potential causative agent of acute gastroenteritis. This study aimed to provide further insight into the currently limited epidemiological data of SalV in environmental water in Thailand, which could be a potential source of human infection. A total of 95 water samples were collected from six locations in Chiang Mai province, northern Thailand, between November 2016 and February 2018. The molecular screening for SalV was performed by the nested polymerase chain reaction. The SalV genotypes were then determined through nucleotide sequencing and phylogenetic analysis. SalV was detected in 31 out of the 95 (32.6%) water samples and all belonged to the A1 genotype, based on phylogenetic analysis of the 5'UTR and 3D regions. The SalV-A1 strains detected in the environmental water were closely related to the SalV-A1 detected in a patient with diarrhoea in the same geographical area, based on the nucleotide sequence identities of the 5'UTR and 3D regions ranging from 91 to 99% and 96-99%, respectively. This study reports the prevalence of SalV-A1 contamination in environmental water in Chiang Mai, Thailand.

UV filters are a group of cosmetic ingredients commonly used in a wide variety of cosmetic products to protect users from UV solar radiation. They belong to different chemical families, such as benzophenones, p-aminobenzoates, salicylates, cinnamates, benzotriazoles, benzimidazoles, camphor derivatives, triazines, etc. These cosmetic ingredients are considered as emerging contaminants since they easily reach the aquatic environment, where they are accumulated causing harmful effects in the flora and fauna despite being present at the ng L-1 level. Therefore, the development of sensitive and selective analytical methods for their environmental surveillance monitoring is of high interest. In this sense, the so-called microextraction techniques play an important role in the sample preparation of environmental water samples. The aim of this review is to compile and discuss the published papers concerning analytical methods for the determination of organic UV filters in environmental water samples based on the use of both sorbent-based and solvent-based microextraction techniques. A special emphasis has been placed on the current trends, i.e., the use of novel (nano)materials and solvents, and the application of the most advanced approaches. The increase in the number of published articles related to the use of these miniaturized techniques reflects their high potential in the determination of organic UV filters in environmental water samples.

A competitive fluorescent aptasensor was constructed based on fluorescence resonance energy transfer (FRET) for determination of 17β-estradiol (E2). Initially, carboxyfluorescein (FAM)-labeled E2 aptamer and its partially complementary DNA modified with Black Hole Quencher 1 (BHQ1) formed aptamer/DNA duplexes and triggered fluorescence quenching. When E2 was added to compete for aptamer-binding sites with cDNA, FAM fluorescence was recovered as a result of cDNA release from the aptamer/DNA duplexes. With a competitive "turn-on" aptasensor, E2 could be quantitatively detected by monitoring fluorescence enhancement. Under optimized conditions, this assay exhibited a linear response to E2 within the range from 0.1 ng·mL−1 to 10 μg·mL−1, with the detection limit of 0.1 ng·mL−1 (0.35 nM). This assay has been successfully applied to determination of E2 in environmental, biological and food samples with low cost and simple pretreatment process, requiring no complicated operations. The results showed high selectivity and good recovery. The present strategy holds great potential in detection of E2 in complex matrixes and becomes important in environmental monitoring, food safety and human health.

Dye effluents released from numerous dye-utilizing industries are harmful towards the environment and living things. Consequently, existence of dye effluent in environmental water bodies is becoming a growing concern to environmentalists and civilians. A long term sustainable and efficient dye effluent treatment method should be established to eliminate this issue. Dye wastewater should be treated first before release to minimize its negative impacts towards the environment and living things. However, due to lack of information on efficient dye removal methods, it is difficult to decide on a single technique that resolves the prevailing dye effluent issue. Therefore, this paper reviews existing research papers on various biological, chemical and physical dye removal methods to find its efficiency through percentage of dye removal. Although there are numerous existing tried and tested methods to accomplish dye removal, most of them have a common disadvantage which is the generation of secondary pollution to the environment. This paper highlights enzyme degradation (biological) and adsorption (physical) dye removal as these are known as one of the most efficient dye removal techniques these days. This paper also suggests the usage of a combined adsorbent as it is envisioned that this technique has better efficiency and is able to remove dyes at a faster rate.

In view of thiophenol contaminants and their adverse effects in environment, it is valuable to develop an effective probe for thiophenols. Based on a large Stokes shift (126 nm) NIR-illuminant platform (Compound 2), we developed a colorimetric and “off-on” near-infrared (NIR) fluorescent probe (NIRP) to selectively discriminate thiophenols from various analytes including aliphatic thiols. NIRP is dually quenched (ICT blocked quenching and PET quenching), thus achieving large signal-to-noise ratio and high sensitivity for thiophenol detection. For the first time, the unique NIR-illuminant phenomenon of 2′ and the d-PET quenching process on NIRP are revealed by the density functional theory (DFT) calculations. Moreover, we demonstrate the practical applications of NIRP, including the quantitative thiophenol detection in environmental water samples and NIR fluorescent imaging of thiophenol in HeLa cells.

A new simple and efficient fluorescent sensor L based on 1,8‑diaminonaphthalene Schiff-base for highly sensitive and selective determination of Cu2+ in drink and water has been developed. This Cu2+-selective detection over other tested metal ions displayed an obvious color change from blue to colorless easily detected by naked eye. The detection limit is determined to be as low as 13.2 nM and the response time is very fast within 30 s. The 1:1 binding mechanism was well confirmed by fluorescence measurements, IR analysis and DFT calculations. Importantly, this sensor L was employed for quick detection of Cu2+ in drink and environmental water samples with satisfactory results, providing a simple, rapid, reliable and feasible Cu2+-sensing method.

Summary A new nanofluidic digital RT-PCR method was developed for sapovirus (SaV) using control material obtained according to standards for enteric viruses. Primers employed amplify a fragment of 112 bp of the polymerase capsid junction, allowing the detection of human genogroups I, II and IV. Analytical validation was performed in clinical, shellfish and environmental water samples. This novel protocol rendered great effectiveness and repetitiveness, as well as higher sensitivity than real time RT-PCR assay, with differences in quantification ranging from 0.1 to 2.6 log-units. The method described here can constitute a promising tool for standardizing SaV quantification.

Nitroaromatic compounds pose a significant risk to human health and other living organisms. However, conventionally high performance liquid chromatography (HPLC) methods are complicated and time-consuming for complete separation of multiple nitroaromatic compounds due to their high structure-similarity. In the work, a facile yet effective strategy, which combines HPLC embedded by diode array detection (HPLC-DAD) with multivariate curve resolution-alternating least squares (MCR-ALS), is explored to improve the HPLC analysis. Based on the strategy, seven nitroaromatic compounds with similar structures could be rapidly quantified under a simple isocratic elution condition (acetonitrile/water: 65:35, v/v) within 10 min. With the aid of the second-order advantage of MCR-ALS, acceptable quantification results are still achieved for the real water samples, despite of significantly overlapping peaks resulted from the similar structures of the analytes and the unexpected interferences from the real water sample. The error analysis and the elliptical joint confidence region (EJCR) test further confirm the reliability of the predicted result. Thereby, the HPLC method coupled with the second-order calibration algorithm could provide a simple, quick and accurate strategy for simultaneous determination on the multiple nitroaromatic compounds in environmental monitoring.

Polydopamine polystyrene nanofibers mat (PDA-PS NFsM) was prepared as an adsorbent for the simultaneous removal of multiple antibiotic residues in environmental water for the first time. PDA-PS NFsM can directly be used to adsorb 18 antibiotic residues belonging to 8 classes without any pretreatment of water samples. The adsorption process was completed within 5 min. All antibiotics could be removed at the same time, and the removal rate of each target was above 85%. Moreover, the used PDA-PS NFsM can be easily separated from the environmental water by taking out directly, and can be reused for 10 times after simple regeneration. The thermodynamic and kinetic properties of PDA-PS NFsM adsorption of antibiotic residues were further investigated consequently. It was found that the adsorptions of PDA-PS NFsM to the targets were spontaneous and endothermic process (ΔG 0, ΔS>0). The results of adsorption kinetic experiments illustrated that the adsorption process was rapid, the adsorption equilibrium of which can be reached in 5 min. Adsorption isotherm experiments proved that the adsorption process of PDA-PS NFsM was consistent with Langmuir adsorption (R2 > 0.994), and the maximum adsorption capacity of PDA-PS NFsM towards all targets were 123.76 mg g−1. The developed method is rapid and simple, and can efficiently adsorb and remove a variety of antibiotics in environmental water, which has good practical application prospect.

We evaluated the diagnostic performances of two media (BCYE, MWY) on 951 Legionella-positive hospital water samples. MWY allowed detecting Legionella in 89.2% of samples, but in 10.8% (103/951) Legionella was found on BCYE plates only. In samples where Legionella was isolated with other micro-organisms (663/951), MWY was essential to detect the majority of positive samples (349/663, 52.6%), as fewer plates resulted unreadable; however, in those containing Legionella only, a higher frequency of positive samples was recorded with BCYE (94.8%, 273/288) compared to MWY (85.1%, 245/288). Considering the 484 concordant positive samples, overall Legionella counts were significantly higher on BCYE (P=0.0029), with 47% of samples showing higher counts on BCYE compared to MWY plates. Furthermore, discordant samples (positive on only one medium) showed different relative proportions between Legionella pneumophila and non-pneumophila, the latter being found more frequently on BCYE only (P=0.0296).Our findings confirm the appropriateness of the ISO 11731:2017 update.

Ultra-sensitive detection of 2,4,6-trinitrotoluene (TNT) plays an important role in society security and human health. The Raman probe molecule p-aminothiophenol (PATP) can interact with TNT in three ways to form a TNT-PATP complex. In this paper, a ‘sandwich’ structure was developed to detect TNT with high sensitivity. Au nano-pillar arrays (AuNPAs) substrates modified by low-concentration PATP through Au–S bonds were acted as capture probe for TNT. Meanwhile, Ag nano-particles (AgNPs) modified by PATP at higher concentration were employed as tags for surface-enhanced Raman scattering (SERS). The formation of the TNT-PATP complex is not only the means by which AuNPAs substrates recognize and capture TNT, but also links the SERS tags to TNT, forming an AuNPAs-TNT-AgNPs ‘sandwich’ structure. The Raman signal of PATP was greatly enhanced mainly because novel ‘hot spots’ formed between the AuNPAs and AgNPs of the ‘sandwich’ structure. The Raman signal of PATP was further amplified by the chemical enhancement effect induced by the TNT-PATP complex formation. Based on this mechanism, the limit of detection (LOD) of TNT was determined from the Raman signal of PATP. The LOD reached 10−9 mg/mL (4.4 × 10−12 M), much lower than that suggested by the US Environmental Protection Agency (88 nM). Moreover, TNT was selectively detected over several TNT analogues 2,4-dinitrotoluene (DNT), p-nitrotoluene (NT) and hexogen (RDX). Finally, the ‘sandwich’ structure was successfully applied to TNT detection in environmental water and sand.

Enrofloxacin (ENR) is a broad-spectrum fungicide that has been largely applied in pharmacy and animal-specific medicine. In this paper, a simple, novel and highly sensitive molecularly imprinted electrochemiluminescence (MIP-ECL) sensor based on mercaptopropionic acid-functionalized copper nanoclusters (MPA-Cu NCs) was developed to selectively detect enrofloxacin (ENR). MPA-Cu NCs prepared by a one-step method were used to modify the glassy carbon electrode. A molecularly imprinted polymer film containing the cavity was constructed after electropolymerization and elution. Under optimized conditions, the MIP-ECL sensor could detect ENR in the range of 0.1 nM–1 μM (R2 = 0.9863) with a low limit of detection of 27 pM, and the recovery rates of ENR in biological and lake water samples were 88.20–105.0%. The MIP-ECL sensor provided path to improve the stability issues of Cu NCs, which might open promising avenues to develop new ECL systems for biological analysis and environmental water monitoring.

Paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper by using dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) was then applied as a paper-based thin film microextraction (p-TFME) to extract four representative sulfonamides (SAs) drugs, which were sulfadiazine, sulfachloropyridazine, sulfamethoxazole, and sulfadimethoxine in environmental water samples. Besides, p-Poly-(MMA-IL) was successfully characterised by FTIR, FESEM, and XRD techniques and underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed method (p-Poly-(MMA-IL)-TFME) was evaluated and applied to analyse SAs in environmental water samples by using a high-performance liquid chromatography-diode array detector (HPLC-DAD). The validation method showed that a good linearity (0.50 µg L-1 –500 µg L-1) was noted (R2 > 0.999, n = 3). Detection and quantification limits were within 0.14 µg L-1 – 0.52 µg L-1 and 0.41 – 1.57 µg L-1, respectively, the preconcentraction factors were > 14.95, and the matrix effect was less than 2.64%, an acceptable percentage for real samples analysis. The extraction recoveries of environmental water samples were ranged from 90.4% to 109.9% with a relative standard deviation (RSD) of less than 9.8%. The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) for analysis of SAs under the p-TFME procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and practicable in the daily analysis.

A green and convenient anhydrous method was developed to synthesize hydrophilic carbon dots (H-CDs) on large-scale in this work. During the whole process of preparation, toxicity materials and high pressure conditions were not used, and H-CDs can be formed in several minutes by directly putting glucose powder into hot edible oil, which can be used again. Therefore, it is a green method and very suitable for the industrial preparation of CDs on large-scale. Characterizations demonstrate the H-CDs possess excellent optical properties, higher photostability and very low cytotoxicty. Noticeably, the H-CDs exhibit a distinct pH-sensitive feature, and have been used to construct fluorescent pH sensor with a nice linear relationship in the pH range of 3.0–13.0. To the best of our knowledge, this is the broadest reported pH range based on carbon dots without heteroatom doped. The mechanism of pH-sensitive response was also discussed. The proposed pH sensor has been successfully used for the pH monitoring of environmental water samples and living cells, which demonstrates their applicability in complex matrixes.

This study aimed to investigate the efficiency of 3A zeolite as a novel adsorbent for removal of Rhodamine B and Malachite green dyes from water samples. To increase the removal efficiency, effecting parameters on adsorption process were investigated and optimized by adopting Taguchi design of experiments approach. The percentage contribution of each parameter on the removal of Rhodamine B and Malachite green dyes determined using ANOVA and showed that the most effective parameters in removal of RhB and MG by 3A zeolite are initial concentration of dye and pH, respectively. Under optimized condition, the amount predicted by Taguchi design method and the value obtained experimentally, showed good closeness (more than 94.86%). Good adsorption efficiency obtained for proposed methods indicates that, the 3A zeolite is capable to remove the significant amounts of Rhodamine B and Malachite green from environmental water samples.

In present study, a stable and magnetic metal-organic framework (MOF) material was synthesized by simple solvothermal method as adsorbent to rapid removal of two organic dyes, the Rhodamine B (RB) and Rhodamine 6G (Rh6G), in water samples. The prepared material showed great characteristics of large surface area (519.86 m 2 g −1 ), excellent magnetic responsivity (35.00 emu g −1 ) and rapid removal (within 5 min). Maximum adsorption capacities of the magnetic material toward RB and Rh6G were up to 219.78 and 306.75 mg g −1 , respectively. Adsorption kinetics suggested the adsorption process met the pseudo-second-order kinetic model. The prepared material could be reused at least 10 times by washing with acetonitrile solution, the relative standard deviation (RSD) of these ten cycles removal efficiency was 4.8%. In conclusion, good chemical inertness, a mechanical/water stability and super-hydrophilicity feature made this MOF a promising adsorbent for targets removal from environmental water sample.

A novel fluorescent chemodosimeter for thiophenols has been readily developed from a red emitting Indole-BODIPY . The chemodosimeter displays a significant fluorescence turn-on response towards thiophenols based on nucleophilic substitution reaction. A linear relationship was obtained between the fluorescence intensity and the concentrations of thiophenols ranging from 0 to 1.8 μM. The chemodosimeter can determine thiophenols (4-fluorothiophenol, 4-methoxybenzenethiol, p -toluenethiol) with high selectivity, fast response (within 8 min) and extremely low limit of detection (9.8 nM). The chemodosimeter was successfully used to determine the level of thiophenol (PhSH) in industrial wastewater and Bohai Sea water with good recoveries. Furthermore, the chemodosimeter was employed to image thiophenols in cancer cells with good performance and low cytotoxicity. Therefore, this chemodosimeter has great potential application in environment.

Hexavalent chromium (Cr(VI)), a highly toxic heavy metal ion, poses a serious threat to human health, and the demand of rapid detection still on-going. Herein, we propose a surface-enhanced Raman spectroscopy (SERS)-based method for rapid and cost-effective quantification of Cr(VI) in aqueous solutions with direct signal of Cr(VI) rather than indirect signals of Raman reporter molecules exploited in previous studies. This method demonstrates high sensitivity (the detection limit of 0.72 ppb), high reproducibility (the batch-to-batch variation was less than 10 %), and excellent selectivity. The results of this proposed method are fairly in good agreement (R2 = 0.991) with those of the UV colorimetric method promulgated by the United States Environmental Protection Agency (USEPA). We demonstrated the potential of our novel method for practical application in determining Cr(VI) concentrations in drinking and environmental water samples, in which adequate recovery, and high interference resistance were observed. This method has the advantages of being faster and suitable for on-site inspection as no pretreatment process is required and the equipment is portable. The excellent performance promises a great prospective toward a rapid, reliable, and on-site detection for Cr(VI).

A phthalazine derivative 13-(4-bromophenyl)-3,3-dimethyl-3,4-dihydro-1H-indazolo [1,2-b] phthalazine-1,6,11(2H,13H)-trione based fluorescent organic nanosheets (IDP NS) were prepared by a simple reprecipitation method in an aqueous medium. It can display turn-off type fluorescence with high selectivity and sensitivity for simultaneous recognition of Cr6+ and Mn7+ among other biologically important cations and anions. Under the selected optimized conditions, the fluorescent intensity of IDP NS studied at an excitation wavelength of λex = 360 nm was quenched gradually by the continuous addition of concentrations of Cr6+ and Mn7+ ions. Moreover, the fluorescence quenching experimental data found to fit the Stern–Volmer relationship in the concentration range of 0–50 μg.mL−1 and 0–80 μg.mL−1 with a limit of detection (LOD) 0.0715 µM and 0.0739 µM towards Cr6+ and Mn7+ respectively. This method based on fluorescence quenching was successfully used for the quantitative determination of Cr6+ and Mn7+ in different environmental water samples.

The development of small molecule fluorescent probes for detection of heavy metal ions is highly desirable in fluorescent sensors area, and mercury (Hg2+) is a heavy metal pollutant in environment and food chain processes. Herein, we reported the design and synthesis of a novel berberine-based fluorescent probe P1, which can specifically recognize Hg2+ in CH3OH/PBS (8:2, v/v, pH = 7.4, 10 mM) solution by the colorimetric and fluorometric changes. The probe P1 displayed high selectivity, superior sensitivity and fast response toward Hg2+ with a low detection limit and a wide range of pH values. This probe can provide a convenient and effective way for Hg2+ detection on test paper strips. Moreover, the probe P1 can be applied to quantitatively detect Hg2+ in real environmental water samples.