Environmental Water Samples Research Articles

Sensitive and specific detection of trace Al3+ ions using an upconversion nanoparticle-xylenol orange complex via the inner filter effect.

We have developed a novel fluorescence sensor based on upconversion nanoparticles (UCNPs) for the rapid and sensitive detection of trace aluminum ions (Al3+). The sensor utilizes the inner filter effect (IFE) between the UCNPs and the xylenol orange-aluminum complex (XO-Al3+), resulting in significant fluorescence quenching at 543 nm upon Al3+ binding. This quenching correlates directly with the Al3+ concentration, allowing for quantitative detection within a range of 0-30 μM and achieving an ultra-low detection limit of 0.19 μM. Selectivity of the sensor is enhanced by the incorporation of ascorbic acid, which masks interfering Fe3+ ions, thus ensuring accurate determination of Al3+ even in the presence of other metal ions. The UCNPs-XO sensor exhibits excellent stability and reproducibility, and minimal interference from commonly co-existing substances. This makes it suitable for the detection of Al3+ in various matrices, including food products and environmental water samples. Our work offers a significant advancement in Al3+ detection, with potential applications in food safety, environmental monitoring, and public health.

A water compatible magnetic molecularly imprinted nanocomposite for the class-selective enrichment of quinoxaline-1,4-dioxides in environmental water.

In this work, a novel water compatible core-shell magnetic molecularly imprinted nanocomposite (Fe3O4-COOH@MIPs) was synthesized in an acetonitrile-water reaction system by adopting carboxyl group-functionalized Fe3O4 nanoparticles as the magnetic core, olaquindox as the template molecule and acrylamide as the functional monomer. The resulting Fe3O4-COOH@MIPs was characterized and applied as an adsorbent for magnetic solid-phase extraction (MSPE) of three quinoline-1,4-dioxides (QdNOs). The Fe3O4-COOH@MIPs possessed strong magnetic responsiveness, fast adsorption equilibrium rate (equilibrium within 5 min) and excellent selectivity. By coupling Fe3O4-COOH@MIPs based MSPE with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), good linearity (R2 ≥ 0.9985) and low limits of detection (0.83-5.0 ng L-1) for QdNOs were obtained. Finally, the proposed method was applied to determine trace QdNOs in environmental water samples, and the recoveries were in the range of 68.08-99.88% with RSD less than 12.5%.

A MnO2 nanosheet-mediated CRISPR/Cas12a system for the detection of organophosphorus pesticides in environmental water.

Nowadays, easy, convenient, and sensitive sensing strategies are still critical for organophosphorus pesticides in environmental water samples. Herein, a novel organophosphorus pesticide (OP) assay based on acetylcholinesterase (AChE) and a MnO2 nanosheet-mediated CRISPR/Cas12a reaction is reported. The single-strand DNA (ssDNA) activator of CRISPR/Cas12a was simply adsorbed on the MnO2 nanosheets as the nanoswitches of the assay. In the absence of target OPs, AChE hydrolyzed acetylcholine (ATCh) to thiocholine (TCh), which reduced the MnO2 nanosheets to Mn2+, resulting in the release of the activator followed by activation of the CRISPR/Cas12a system. The activated Cas12a thereafter nonspecifically cleaved the FAM/BHQ1-labeled ssDNA (FQ-reporter), producing a fluorescence signal. Upon the addition of target OPs, the hydrolysis of ATCh by AChE was inhibited owing to OPs combining with AChE, and thus effective quantification of OPs could be achieved by measuring the fluorescence changes of the system. As a proof of concept, dichlorvos (DDVP) was chosen as a model OP analyte to address the feasibility of the proposed method. Attributed to the excellent trans-cleavage activity of Cas12a, the fluorescent biosensor exhibits a satisfactory limit of detection (LOD) for DDVP at 0.135 ng mL-1. In addition, the excellent recoveries for the detection of DDVP in environmental water samples demonstrate the applicability of the proposed assay in real sample research.

Cobalt-nickel phosphide supported on reduced graphene oxide for sensitive electrochemical detection of bisphenol A

Bisphenol A (BPA) is a commonly utilized phenolic contaminant in several manufacturing processes, contributing to environmental pollution. Therefore, the detection of BPA holds significant importance for monitoring water quality. In this work, we report a robust electrochemical detection method for BPA utilizing cobalt−nickel bimetal phosphide nanoparticles (CoNiP) supported on reduced graphene oxide (rGO). The CoNiP@rGO-modified glassy carbon electrode exhibits remarkable electrochemical activity in BPA detection. The detection mechanism is controlled by adsorption-mediated electron transfer, showcasing a low limit of detection (LOD) at 0.38 nM and a high sensitivity of 96.4 A M−1 cm−2 within the linear range of 0.001–8 μM. Furthermore, our developed sensor demonstrates good reproducibility and successfully detected BPA in actual water samples. The electrochemical activity of CoNiP@rGO was also characterized for hydroquinone (HQ) detected through a diffusion-controlled mechanism, displaying an excellent sensitivity of 36.4 A M−1 cm−2 across a broad linear range. These findings underscore the promising potential of CoNiP@rGO as a candidate for electrochemical detection of phenolic contaminants, especially in the sensing of BPA in environmental water samples. This efficacy is attributed to the modulation of its electronic properties, combined with its large electroactive surface area and low electron-transfer resistance.

A ratiometric fluorescent probe with a large Stokes shift for the detection of Hg2+ and its applications in environmental sample and living system analysis.

Toxic mercury ions (Hg2+) can cause serious environmental pollution and accumulate in living organisms via the food chain. Therefore, monitoring Hg2+ is crucial in ensuring the safety of ecosystems and organisms. In this work, a novel ratiometric fluorescent probe CMT (5-(4-(diphenylamino)phenyl)-1-(7-hydroxy-coumarin-3-yl)-4-pentene-1,3-dione) based on coumarin was developed for detecting Hg2+, which displayed obvious fluorescence changes, a low detection limit (2.24 × 10-7 M), good selectivity, and a large Stokes shift (255 nm). The CMT probe could detect Hg2+ in real environmental soil and water samples. Furthermore, the CMT probe enabled the naked-eye detection of Hg2+ using test paper experiments. CMT was also applied for fluorescence imaging in living zebrafish and plants. This work provides a highly efficient tool for monitoring Hg2+ in environmental samples and biological systems.

Hollow CoZnSe@CN nanocage with enzymatic activity for determination of tetracycline using smartphone platforms and virtual reality revealing.

Antibiotic residues in the environment pose a serious threat to ecosystems and human health. Therefore, it is important to develop sensitive and rapid in situ detection methods. In this work, the designed nanozymes, with excellent four enzyme activities, were proved to be constituted ofunique hollow nanocage structures (CoZnSe@CN HCs). Based on the peroxidase-like enzymes, a portable colorimetric sensor was constructed for the on-site determinationof tetracycline (TC) in real samples. The linear range of TC detection was 0.1-100μM, and the detection limit was 0.02μM. At the same time, colorimetric detection and smartphones have also been combined for on-site colorimetric detection of TC. In-depth exploration of the detection mechanism showed that TC could be bound with the material, inhibiting the production of oxidized 3,3',5,5'-tetramethylbenzidine. The sensor was also used for the detection of TC in environmental soil and water samples. This study can provide an intelligent detection method for environmental monitoring.

Rapid colorimetric sensing of chlorpromazine HCl antipsychotic through in situ growth of gold nanoparticles.

Antipsychotic drugs like chlorpromazine hydrochloride (CPZ) are widely used to treat mental illnesses but can accumulate in the environment if not properly disposed of. Long-term exposure to trace levels of such pharmaceuticals may pose health risks. This study reports a colorimetric assay for detection of the antipsychotic drug chlorpromazine hydrochloride (CPZ) based on its ability to reduce gold ions and form gold nanoparticles (AuNPs). Optimization of reaction conditions such as pH, temperature and reagent concentrations enabled quantitative analysis of CPZ concentrations from 0.1-30 μg mL-1, with a detection limit of 0.06 μg mL-1, 0.23 μg mL-1 quantification limit and less than 3.5% RSD. The AuNPs exhibited a characteristic surface plasmon resonance band at 527 nm detectable by UV-vis spectrophotometry. Method validation with spiked serum, urine and environmental water samples demonstrated acceptable accuracy and precision. Interfering substances showed minimal impact, indicating resilience and specificity. This rapid, inexpensive colorimetric assay could facilitate environmental monitoring and biomedical analysis of antipsychotic drugs.

Facile synthesis of sulphur-doped carbon dots (S-CDs) using a hydrothermal method for the selective sensing of Cr6+ and Fe3+ ions: application to environmental water sample analysis.

In this work, we used a one-step hydrothermal method to synthesize blue-emission sulfur-doped carbon dots (S-CDs) using jaggery as a carbon precursor. The synthesized carbon quantum dots showed low toxicity, good water solubility, anti-interference properties, and stable fluorescence. When excited at 310 nm, the S-CDs produced bright emission with a quantum yield of 7.15% at 397 nm. The S-CDs exhibited selective and sensitive quenching responses with limits of detection (LODs) of 4.25 μg mL-1 and 3.15 μg mL-1 for variable concentrations of Cr6+ and Fe3+, respectively, accompanied by a consistent linear relationship between fluorescence intensity and these concentrations. Fluorescence lifetime measurements were used to investigate the fluorescence quenching mechanism, which supports the static type of quenching. Outstanding benefits of the developed S-CD based fluorescence probe include its low cost, excellent sensitivity and selectivity, and ease of use for the detection of Cr6+ and Fe3+ ions. The developed carbon dot based fluorescent probe was successfully used to detect Cr6+ and Fe3+ ions in real water samples with an excellent recovery ratio.

Solid-phase extraction (SPE) of Ni(II), Cd(II) and Pb(II) ions using pyromellitic dianhydride functionalized silica gel prior to flame atomic absorption spectrometric determination

In this work, a novel pyromellitic dianhydride modified silica gel (PMDA-SG) was firstly fabricated for column solid-phase extraction (SPE) of Ni(II), Cd(II), and Pb(II) ions at trace levels from aqueous solutions, aiming to determine their trace level using flame atomic absorption spectrometer. PMDA-SG was confirmed by FT-IR and C,H,N elemental analysis. Optimization of the SPE column for Ni(II), Cd(II) and Pb(II) ions using the PMDA-SG loaded column involved a comprehensive investigation of the key factors. The optimum conditions were found as follows: a sample solution pH of 7.0, a sample flow rate of 5 mL/min, a maximum solution volume of 500 mL, and an eluent consisting of 5 mL of 1.0 mol L−1 HNO3 solution. To validate the developed SPE method, a certified reference material of Ontario Lake water (NWTMDA-54.4) was employed, and a good fit was observed in the obtained data. The SPE method demonstrated good precision in the determination of Ni(II), Cd(II) and Pb(II) at 20 ng mL−1 (n = 5), yielding relative standard deviation values lower than 5%. Trace levels of Ni(II), Cd(II) and Pb(II) in environmental water samples form laboratory tap, Sapanca Lake, Çark Stream and Sakarya River were successfully quantified by FAAS after preconcentration using PMDA-SG filled column.

Fabrication of a β-CD-functionalized magnetic microporous organic network for effective enrichment and detection of fluoroquinolone antibiotics in water samples.

Fluoroquinolone (FQ) antibiotics, one of the leading environmental pollutants, have ecotoxic effects that can accumulate through ecosystems and harm human health. The determination of FQs is still difficult due to the complex matrix, many interfering factors, and low concentration. Hence, a magnetic microporous organic network (MON) composite denoted as Fe3O4@MON-NH2@CM-β-CD with excellent FQ adsorption performance was prepared by β-CD covalent modification of a MON. Based on the existence of π-π packing, hydrophobic interaction, and hydrogen bonding between Fe3O4@MON-NH2@CM-β-CD and FQs, a new magnetic solid phase extraction (MSPE) method for the enrichment of FQs was developed. Under optimized MSPE conditions, five FQs were detected by HPLC-UV with good linearity (R2 ≥ 0.9989) in the range of 0.02-1 μg mL-1, and detection limits (S/N = 3) in the range of 0.0014-0.0023 μg mL-1. The satisfactory recoveries ranged from 93.1 to 116.2% with RSDs lower than 8.39% when applied to actual environmental water samples. These results revealed that Fe3O4@MON-NH2@CM-β-CD as an adsorbent for MSPE had excellent performance for FQ extraction from real samples, and the MON material types were expanded through the functionalization of MONs, which would have great potential for further application in various analytical methods.

γ-mercaptopropyltrimethoxysilane Coated Stir Bar Sorptive Extraction Combined with Inductively Coupled Plasma Mass Spectrometry for the Determination of Copper, Cadmium, and Mercury in Environmental Water Samples

γ-mercaptopropyltrimethoxysilane Coated Stir Bar Sorptive Extraction Combined with Inductively Coupled Plasma Mass Spectrometry for the Determination of Copper, Cadmium, and Mercury in Environmental Water Samples

Potentiometric Monitoring of Iodide Ions Using a Highly Selective Iodide Sensor Based on AgI-Cu2S-Multi Walled Carbon Nano Tube Material

In this work, a new iodide selective sensor based on an AgI-Cu2S-Multiwalled carbonnanotube-Graphite-Paraffin oil composite material was described for highly selective potentiometric determination of iodide ions. To obtain the best potentiometric performance characteristics of the sensor, the sensor components was optimized and the sensor was formed by properly pressing of the optimized sensor components. The experimental results were showed that the most appropriate potentiometric response was achieved with the sensor materials containing a compositions of G:MWCNT:AgI:Cu2S:PO in the ratio 50:5:20:5:20 (% w/w). The developed sensor display a wide linear working range (1.0×10-5-1.0×10-1 molL-1) for iodide ions. In this linear working range, the Nernstian slope of the sensor was 51.5±1.0 mV and the correlation coefficient (R2) was determined as 0.9991. The sensor was of a very low response time (5s). The repeatability of the sensor potential response was very good and its response remained unchanged in the pH range of 6.0-9.0. The interference effect on the sensor response of different anionic species was tested by the separate solution method (SSM) and the sensor selectivity was quite good. The life time of the sensor was measured as 13 weeks and the sensor was successfully used as indicator sensor for the potentiometric titrations of iodide ions with silver nitrate solution. Additionally, the sensor was successfully applied for the direct detection of iodide ions in environmental water samples.

An environmentally friendly microextraction method for the determination of cadmium in water samples

An environmentally friendly switchable solvent based microextraction method was developed for cadmium ions prior to determination by FAAS. N, N-dimethyl-n-octylamin and 1-(2-Pyridylazo)-2-naphthol were used as switchable solvent and ligands, respectively. Important method parameters such as pH, amount of extraction solvent and ligand, volume of sample and NaOH and foreign ions effects have been optimized. Limits of detection and quantification, preconcentration factor were determined as 0.063 mg L-1, 0.21 mg L-1 and 60, respectively. The validation study of the developed method was carried out by spiking a fixed amount of cadmium to the water samples and determining the recovery. The method was used to determine the cadmium ions content of various environmental water samples.

A thiophene-linked terpyridine based phenanthridine chemoreceptor for Cd2+ and Cr3+ selective ratiometric fluorescence detection in environmental water and rice samples

BackgroundThe studied materials, Cadmium (Cd2+) and Chromium (Cr3+) are highly toxic, and it focuses on investigating various environmental sources, such as industrial processes and waste water. When quantities of Cr3+ and Cd2+ exceed the allowable limit, biological toxicity and hazardous environmental pollution are unavoidable. In order to address this problem, we introduce 5-(5-(4-([2,2':6′,2″-terpyridin]-4′-yl) phenyl) thiophen-2-yl)-7,8,13,14-tetrahydrodibenzo [a,i] phenanthridine (TPTP), a dual-emission response chemosensor that employs a colorimetric and fluorescence turn-on approach for the rapid, sensitive, and discriminate detection of Cr3+ and Cd2+ ions. ResultsWe created a newly designed luminous TPTP sensor based on intramolecular charge transfer (ICT). TPTP sensor probe specifically determined Cr3+ and Cd2+ ions with an immediate colour shift from cyan to green and orange in CH3CN: H2O (6:4) solvent solution. The permissible level set by the Environmental Protection Agency (EPA) of the United States for the presence of Cr3+ and Cd2+ ions in drinking water was higher than the detection level of 3.5 and 9.7 nM, by this sensor respectively. NMR titrations, HRMS, and theoretical calculation methods were employed to examine the accurate sensing processes of TPTP and complexes. SignificanceThis is an effective method of detecting Cr3+ and Cd2+ ions in an environmental system using a ratiometric methodology. In addition, TPTP was used to determine the concentration of Cr3+ and Cd2+ ions in natural water and food samples. Fluorescent bio-imaging studies revealed that the present sensor TPTP could identify Cr3+ and Cd2+ ions inside living HeLa cells. A paper kit analysis has been done on TPTP, which has a time-to-result of less than 1 s and offers a cost-effective assay. As a result, the platform offers portability.

Rapid extraction and separation of mercury in water and food samples based on micelles and azo-thiazoles complexation before determination by UV-Vis spectrophotometer

A simple and sensitive procedure has been established for analyzing mercury (II) ions spectrophotometrically in the presence of micellar medium using three azo-thiazoles complexing reagents: 2-amino-6-(thiazole-2-yldiazenyl)-3-pyridinol (C8H7N5OS), 8-hydroxy-7-(thiazole-2-yldiazenyl) quinoline-5-sulfonic acid (C12H8N4O4S2), and 1-hydroxy-4-(thiazole-2-yldiazenyl)-2-naphthoic acid (C14H9N3O3S). H1 NMR spectra validated the three azo thiazoles synthesized material. Tween 80 (polysorbate 80) and cetyltrimethylammonium bromide (C19H42BrN as molecular biology) are micellar mediums to enhance sensitivity. Absorbances were measured for Hg (II) complexation with R1, R2, and R3 at λmax of 617, 633, and 554 nm, respectively. The UV-Vis spectrophotometer showed calibration curves in the 0.2-15 mg L-1. The molar absorptivity, Sandell's sensitivity, detection, and quantification limits (LOD, LOQ) were determined. The interferences of various ions were investigated, and a statistical assessment of the results was performed. The methods have been applied for trace determination of mercury (II) in food and environmental water samples. For food samples, all samples were digested before complexation with the azo-thiazoles material at optimized pH before determination by UV-Vis spectrophotometry.

Use of magnetic nanoparticles in an Ionic liquid (BMIM-PF6) based vortex‐assisted dispersive liquid–liquid microextraction (VSLLME) for measuring the traces amounts of cadmium in environmental, biological and nutritional samples

In the present project, the magnetic nanoparticles were used in a type of an ionic liquid based micro-extraction to measure trace amounts of cadmium in different real samples containing environmental water samples, saliva and human hair. In the optimum condition, the recovery percentages for the real sample were about 94.5% to 101.3%, showing the designed method is suitable to be used for analyzing the real environmental and biological samples. The main parameters were evaluated and optimized as follows: pH was 2.5, the volume of ionic liquid was 150 µl, the amount of Fe3O4 magnetic nanoparticles was 50mg, the volume of the complexing agent was 12 µl, and the vortex time was 1 min and 2 min for ionic liquid, and magnetic nanoparticle distribution steps, respectively. Also, the volume of the medium was 10 to 20 ml.

THE EFFECT OF ESCHERICHIA COLI BACTERIOPHAGE COCKTAIL ON BACTERIAL CONTAMINATION IN WATER

Objective: Wastewater and environmental water resources are treated to eliminate pathogenic microorganisms but contamination is still a significant problem. In particular, the presence of contamination with Escherichia coli (E. coli) is an important indicator of fecal contamination. Due to increasing antimicrobial resistance and failures of new antimicrobial processes, interest in bacteriophages in pathogen control has increased. Therefore, in our study, phage-based bacteria control in environmental waters was investigated as a natural solution. Material and Method: In our study, E. coli and lytic bacteriophages specific to these E. coli were isolated from environmental water samples in Ankara. The lytic activities of the isolated phages were determined on environmental and clinical extended-spectrum β-lactamases E. coli isolates. Three phages with high lytic activity were selected, and the effectiveness of the single phage and their mixtures on E. coli contamination in water was tested. Result and Discussion: As a result of the study, 17 E. coli strains were isolated from 30 environmental water samples. Lytic bacteriophages in 30 different plaque structures were also isolated from water samples. The isolated phages were found to have lytic activity in the range of 32-70% on the tested bacteria. The effectiveness of three selected phages and their cocktail on E. coli contamination in water was measured at 6th and 24th. As a result, it was observed that the cocktail application reduced the number of host bacteria in the water below detectable limits, also provided a 5-log reduction in non-host test bacteria and maintained its effect for 24 hours. When the results are evaluated, it is thought that cocktail phage application will be an effective method against E. coli contamination in water.

Novel electrochemical sensing strategy for ultrasensitive detection of tetracycline based on porphyrin/metal phthalocyanine-covalent organic framework

In this work, a novel two-dimensional semiconducting metal covalent organic framework (CuTAPc-TFPP-COF) was synthesized and used as biosensing platform to construct aptasensor for trace detection of tetracycline (TC). The CuTAPc-TFPP-COF integrates the highly conjugated structure, large specific surface area, high porosity, abundant nitrogen functional groups, excellent electrochemical activity, and strong bioaffinity for aptamers, providing abundant active sites to effectively anchor aptamer strands. As a result, the CuTAPc-TFPP-COF-based aptasensor shows high sensitivity for detecting TC via specific recognition between aptamer and TC to form Apt-TC complex. An ultralow detection limit of 59.6 fM is deduced from the electrochemical impedance spectroscopy within a wide linear range of 0.1–100000 pM for TC. The CuTAPc-TFPP-COF-based aptasensor also exhibits good selectivity, reproducibility, stability, regenerability, and excellent applicability for real river water, milk, and pork samples. Therefore, the CuTAPc-TFPP-COF-based aptasensor will be promising for detecting trace harmful antibiotics residues in environmental water and food samples.

A dual-functional fluorescence probe CDs@ZIF-90 for highly specific detection of Al3+ and Hg2+ in environmental water samples

In recent years, the escalating water pollution has resulted in serious harm to human health and ecological environment due to the excessive discharge of toxic metal ions such as Al3+ and Hg2+. Therefore, it is crucial to develop a simple, efficient, and rapid detection method for monitoring the levels of the metal ions in water environment to ensure public health and ecological safety. In this study, carbon dots (CDs) containing heteroatom Si were successfully synthesized by the solvothermal method. Subsequently, a novel dual-functional fluorescent sensor (CDs@ZIF-90) was constructed by integrating CDs with zeolitic imidazolate framework-90 (ZIF-90). The fluorescent composite CDs@ZIF-90 showed outstanding optical properties and excellent structural and luminescence stability in aqueous medium. Particularly, its fluorescence at 453 nm can be remarkably enhanced by Al3+ and quenched upon exposure to Hg2+. As a result, the CDs@ZIF-90 was applied in sensitive and selective determination of Al3+ and Hg2+ ions with wide linear ranges (1–200 μM and 0.05–240 μM) and low detection limits (0.81 μM and 19.6 nM). Moreover, a convenient and rapid fluorescence test strip was also successfully prepared for visual detection of Al3+ and Hg2+ ions. This work is the first try to use the CDs@ZIF-90 fluorescence sensing material for highly sensitive and selective determination of Al3+ and Hg2+ based on “turn-on” and “turn-off” dual modes, respectively and it provides a new idea for monitoring quality of drinking water and environmental water. It is of great significance for human health and environmental protection.

Assessment of PCR Inhibitor Removal Methods to Monitor Viruses in Environmental Water Samples: DAX-8 Outperforms Competitors

Complex water matrices or viral elution buffers can interfere with the qPCR leading to an underestimation of the potential public health hazards of waterborne viral pathogens. Here, we assessed different approaches to mitigate inhibitory impact of complex water samples during RT-qPCR of murine norovirus (MNV), as an inhibition control. The dilution of extracted samples, the use of qPCR additives, a commercial PCR inhibitor removal kit, and polymeric adsorbents such as Supelite DAX-8 and polyvinylpyrrolidone (PVP) were all investigated in this context. Data indicated that the maximum amplification of MNV by RT-qPCR could be obtained by pre-dilution of samples. However, the dilution factor may depend on inhibitors concentration, primer length, probe sequence, and binding capacity. Interestingly, PCR inhibitor removal kits do not seem to be adequate for removing all PCR inhibitors. In comparison to other approaches studied here, the application of 5% DAX-8 led to an increase in MNV qPCR concentrations. DAX-8 can permanently eliminate humic acids from the extracted nucleic acids from the environmental water samples, and it has the potential to considerably improve the accuracy of the obtained non-detects and measured concentrations by qPCR. Further research is required to understand the performance of polymeric adsorbents with enveloped viruses.