Environmental Water Samples Research Articles

Molecularly imprinted photonic polymer for rapid visual detection of sulfamethoxazole in environmental water samples

AbstractSulfamethoxazole (SMX) has numerous adverse effects and is present in various water systems; thus, the development of a rapid and accurate analytical method to detect SMX in water systems is crucial for protecting the environment and human health. A sulfamethoxazole molecularly imprinted photonic polymer (MIPP‐SMX) capable of facile naked‐eye recognition of target molecules was synthesized using the dual‐functional monomers acrylamide and methacrylic acid. The color of the MIPP‐SMX changed from green to blue in water samples containing sulfamethoxazole (SMX) in the concentration range of 0.5–5.0 mM. Furthermore, a linear correlation existed between the detected Bragg diffraction peak shift Δλ and SMX concentrations in water ranging from 0.5 to 2.0 mM. The detection limit for SMX was 0.3 mM. A recovery rate of 91.9%–108.5% was achieved when the polymer sensor was used to detect SMX in river water samples, with a relative standard deviation of 4.9%–6.0%. The designed MIPP‐SMX enabled rapid visual detection of SMX in water samples. The proposed method represents a significant advancement in the visual detection of SMX in environmental water samples.

Fe3O4@nitrogen-doped carbon core-double shell nanotubes as a novel and efficient nanosorbent for ultrasonic assisted dispersive magnetic solid phase extraction of heterocyclic pesticides from environmental soil and water samples.

Fe3O4@nitrogen-doped carbon core-double shell nanotubes (Fe3O4@N-C C-DSNTs) were successfully synthesized and applied as a novel nanosorbent in ultrasonic assisted dispersive magnetic solid phase extraction (UA-DMSPE) of tribenuron-methyl, fenpyroximate, and iprodione. Subsequently, corona discharge ion mobility spectrometry (CD-IMS) was employed for the detection of the extracted analytes. Effective parameters on theextraction recovery percentage (ER%) were systematically investigated and optimized. Under optimal conditions, UA-DMSPE-CD-IMS demonstrated remarkable linearity in different ranges within 1.0 - 700 ng mL-1 with correlation coefficients exceeding 0.993, repeatability values below 6.9%, limits of detection ranging from 0.30 to 0.90 ng mL-1, high preconcentration factors (418 - 435), and ER%values (83 - 87%). The potential of the proposed method was further demonstrated by effectively determining the targeted pesticides in various environmental soil and water samples, exhibiting relative recoveries in the range 92.1 - 102%.

Facile colorimetric sensor using oxidase-like activity of octahedral Ag2O particles for highly selective detection of Pb(II) in water

Pb(II) is a prevalent heavy metal ion classified as a 2B carcinogen. Excessive intake of Pb(II) in the human body can damage the central nervous system, kidneys, liver, and immune system, leading to permanent brain damage, anemia, and cancer. Colorimetry can be applied to rapidly determine Pb(II) residues, but there are still many challenges in the accuracy and sensitivity of detection. Based on the inhibitory impact of Pb(II) on the oxidase-like activity of octahedral silver oxide (Ag2O), a colorimetric sensor with smartphone-assisted analysis for the Pb(II) detection was first developed. Herein, it has been found that Pb(II) can adsorb onto the surface of octahedral Ag2O, hindering the production of O2− in the reaction system. This ultimately results in the suppression of oxidase-like activity, leading to a lighter purple appearance of the colorimetric reaction solution. The sensor exhibits a high degree of sensitivity and a limit of detection (LOD) for Pb(II) was calculated as 2.2 μg L−1. Hence, the developed colorimetric sensor with high sensitivity, excellent specificity, and high tolerance to sodium ions is hopeful to have practical applications in Pb(II) detection in environmental water samples. Moreover, the sensor will provide a novel strategy for heavy metal ion detection and other substances.

Acid induced dispersive liquid–liquid microextraction based on in situ formation of hydrophobic deep eutectic solvents for the extraction of bisphenol A and alkylphenols in water and beverage samples

This study describes the development of an acid induced dispersive liquid–liquid microextraction method based on the in situ formation of hydrophobic deep eutectic solvents for the extraction of bisphenol A and alkylphenols from environmental water and beverage samples. Hydrochloric acid altered the hydrophilic-hydrophobic state of fatty acid salts to obtain hydrophobic fatty acids, which formed hydrophobic deep eutectic solvents with analytes in situ to extract the analytes. Under optimized conditions, the limits of detection and limits of quantitation were 0.03–0.1 μg L-1 and 0.12–0.3 μg L-1, the intraday and interday relative standard deviations were less than 3.9 %, and the enrichment factor was 29–32. The recoveries of bisphenol A and alkylphenols were 95.9–104.9 % and 86.9–105.0 %, respectively. The extraction process used only hydrochloric acid and fatty acid salts, and the extraction process required less than 1 min. This method has the advantages of simplicity, speed, low cost and environmental friendliness.

Construction of Co-ZIF-derived CoS2@Cu hollow heterogeneous nanotube array for the detection of hydrazine in environmental water samples

As a neurotoxin, it is necessary to establish a low cost, stable and sensitive method for the quantitative detection of hydrazine. Using Co-ZIF (zeolite imidazole framework) nanorods as precursor, CoS2 hollow nanotube array heterogeneous structure loaded with Cu nanoparticles were prepared on carbon cloth (CC) by etching, calcination and plasma magnetron sputtering (CoS2@Cu HNTA/CC). As a self-supporting electrode, its hollow heterogeneous structure provides a large area of electron transfer channel for the oxidation of the food pollutant hydrazine. In addition, bimetallic synergies and in situ N doping regulated the electronic structure of CoS2@Cu HNTA/CC, and thus significantly improved the electrical conductivity and catalytic activity. As an efficient hydrazine sensor with a wide linear range of 1 μM L−1-10 mM (1 μM-1 mM and 1 mM–10 mM), its sensitivity and the limit of detection are 7996 μA mM−1 cm−2, 3772 μA mM−1 cm−2 and 0.276 μM (S/N = 3), respectively. This study provides a new strategy for the construction of MOFs (Metal Organic Framework)-derived bimetallic composites and their application in electrochemical sensing.

A CRISPR/Cas13a-powered catalytic hairpin assembly evanescent wave fluorescence biosensor for target amplification-free SARS-CoV-2 detection

The end of the coronavirus disease 2019 (COVID-19) pandemic still drives the development of rapid and accurate detection technology to prepare for diverse viral infections and emerging pandemics in the future. Herein, a CRISPR/Cas13a-powered catalytic hairpin assembly evanescent wave fluorescence biosensor (CAPABLE) was developed for amplification-free detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the ingenious design of trigger, the presence of SARS-CoV-2 activated the trans-cleavage activity of Cas13a, followed by the initiation of a catalytic hairpin assembly (CHA) system that exhibited excellent signal amplification efficiency. By integrating the biotin-avidin system, the detection sensitivity of the portable fluorescence platform was greatly improved. Quantitative SARS-CoV-2 detection was realized with a detection limit of 18.6 copies/μL within 50 min based on a fast extraction method. The proposed method exhibited a 100% positive detection rate for environmental water samples spiked with SARS-CoV-2 pseudovirus, which was consistent with standard RTqPCR results. Benefiting from amplification-free performance, the CAPABLE method holds great promise for rapid SARS-CoV-2 detection in field laboratories and primary facilities in resource-limited areas. With the inherent flexibility of the CRISPR/Cas system, the proposed method has the potential to be applied in the diagnosis of various infectious diseases.

Cubic engineering approached a novel needle-structured cobalt-doped zinc oxide interconnected with carbon nanofiber as a composite for the determination of toxic 4-nitrophenol in environmental water samples

It is essential for developing an effective and accurate method for analysis for detecting 4-nitrophenol (4-NP), as its harmful effect is one of the most frequent environmental concerns. In this work, the 4-NP was detected by the CNF/CZO nanocomposite. The cobalt-doped zinc oxide (CZO) was synthesized utilizing a simple hydrothermal technique and carbon nanofiber (CNF) was combined with cobalt-doped zinc oxide (CZO) to get CNF/CZO nanocomposite. The morphological and chemical characteristics of the CNF|CZO nanocomposite have been studied using several characterization techniques. The CZO nanoparticles have equal dispersion across the surface of the CNF and the nanocomposites were modified with a glassy carbon electrode (GCE), which is utilized as a working electrode for the electrochemical studies. Hence, the CNF|CZO the nanocomposite was confirmed using field emission scanning electron microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray analysis, X-ray Diffraction Analysis, and X-ray Photoelectron Spectroscopy, Fourier-transform infrared spectroscopy, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry research, and Differential Pulse Voltammetry studies were done. Hence, the GCE|CNF|CZO electrode displays a low detection limit of 0.2 μM, a wide linear response range of 0.01–520 µM, and a higher sensitivity of 0.0137 μA μM−1 cm−2. Further, the GCE|CNF|CZO electrode detected 4-NP in environmental water samples and also showed exceptional selectivity, repeatability, stability, and reproducibility. Hence, we conclude that GCE|CNF|CZO electrode exhibited good catalytic activity due to the inherent interaction between CNF and CZO providing an electron transfer network and high catalytic activity towards 4-NP detection.

Low-level tritium measurements in freshwater and seawater samples

The aim of this study was to test two potential tritium determination methods (with and without electrolysis enrichment) suitable for low-level measurements. Both methodologies were applied to water samples from the Baltic Sea and ten Polish rivers providing new data on tritium activity concentration. Optimization steps carried out to the standard method lowered minimum detectable activity concentration (MDC) from 3.1 to 1.8 Bq L–1 (at 95% confidence level) enabling to apply it to environmental water samples. However, electrolytic enrichment method of MDC of 0.20 Bq L–1 provided more accurate results for tritium activity concentration in surface waters.

Evaluation of long-term supplementation of a Bacillus subtilis direct-fed microbial and enzymatically hydrolyzed yeast cell culture product used alone or in combination on Clostridia, Clostridium perfringens, Escherichia coli, and Salmonella prevalence in beef steers.

The objective was to determine the influence of long-term supplementation (258 d) of a direct-fed microbial (DFM) and/or yeast cell wall (YCW) product on bacterial populations in beef steers. Single-sourced Charolais × Red Angus steers (n = 256; body weight = 246 ± 1.68kg) were used in a randomized complete block design and blocked by location into one of four treatments: 1) fed no DFM and no YCW (Control); 2) fed only the DFM (DFM; Certillus CP B1801 Dry,28 g/steer d-1 ); 3) fed only the YCW (YCW; Celmanax; 18 g/steer d-1 ); and 4) fed the DFM and the YCW (DFM+YCW). Steers were vaccinated for respiratory and clostridial diseases and treated for internal and external parasites at processing and individually weighed on days 1, 14, 42, 77, 105, 133, 161, 182, 230, and 258. To determine bacterial prevalence, fecal samples were collected on days 1, 14, 77, 133, 182, and 230 and environmental (pen area, feed, and water) samples were collected at the beginning of the week when cattle were weighed. No treatment × day interactions or treatment effects (P > 0.05) were observed between treatment groups at any sampling days for the bacterial populations. Samples on days 1, 133, and 182 had greater (P < 0.05) Clostridia levels compared to the other sampling points but were not different from each other. Clostridia levels were also greater (P < 0.05) on day 77 compared to days 14 and 230. Samples on days 77 and 230 had greater (P < 0.05) Clostridium perfringens levels compared to the other sampling points but were not different (P > 0.05) from each other. Samples on days 1 and 14 had lower (P < 0.05) total Escherichia coli levels compared to the other sampling points but were not different (P > 0.05) from each other. Escherichia coli levels on day 77 were higher (P < 0.05) compared to days 133, 182, and 230. Little Salmonella prevalence (1.5%) was observed throughout the study. This study had greater levels of Clostridia compared to small and large commercial feedlots in the Church and Dwight research database, but C. perfringens, total and pathogenic E. coli, and Salmonella prevalence were notably lower. Collectively, there were no appreciable treatment influences on bacterial populations. These data further indicate a low pathogenic bacterial challenge at the trial site, which could partially explain the lack of differences with DFM or YCW supplementation. The DFM and YCW used alone or in combination cannot be expected to show additional benefits when animals are relatively unstressed with a low pathogenic bacterial challenge.

Surfactant modified coconut husk fiber as a green alternative sorbent for micro-solid phase extraction of triazole fungicides at trace level in environmental water, soybean milk, fruit juice and alcoholic beverage samples.

In this work, micro-solid phase extraction using surfactant modified biosorbent was investigated for trace level determination of triazole fungicides prior to their analysis by high performance liquid chromatography. Coconut husk fiber (CHF) was selected as an effective biosorbent in the extraction process. Fourier transform infrared spectrometry, scanning electron microscopy and transmission electron microscopy methods were used to characterize the modified biosorbent. Various factors affecting the extraction efficiency of the proposed method were studied including the amount of coconut husk fiber biosorbent (0.1 g), kind and concentration of surfactant as a modifier (sodium dodecyl sulfate, 10 mmol L-1), kind and volume of desorption solvent (methanol, 150 μL), and extraction period (including vortex adsorption time, centrifugation adsorption time, vortex desorption time and centrifugation adsorption time approximately 10 min). Under the selected conditions, the calibration plot was found to be linear in the range of 9-300 μg L-1 with a coefficient for determination of greater than 0.99. The limits of detection and limits of quantification for the studied triazole fungicides were 3.00 and 9.00 μg L-1, respectively. Finally, the proposed method was successfully applied to determine triazole fungicides in environmental water, soybean milk, fruit juice and alcoholic beverage samples with acceptable recoveries obtained in the range of 67.0% to 105.0%.

An exceptional water stable terbium-based metal-organic framework for selective detection of pesticides.

A terbium-based metal-organic framework (MOF) with exceptional water stability for highly selective detection of pesticide thiamethoxam (TMX) in aqueous solution is reported. To date, most reported lanthanide metal-organic frameworks (Ln-MOFs) still exhibit poor water stability, which may limit their practical applications in bio-sensing and detecting pollutants in environmental water samples. In this work, a Tb-MOF [Tb(BDC)1.5(DEF)·0.5H2O] n (1, BDC = 1,4-benzene dicarboxylate, DEF = N,N-diethylformamide) was prepared by hydrothermal reactions of 1,4-benzenedicarboxylic acid with the corresponding rare earth ions of Tb3+. Impressively, water stability surveys of compound 1 indicated that it maintained at least 90% of its emission intensity after storage in water for several months. This characteristic of long water stability is unusual as compared to other Ln-MOFs, making compound 1 an excellent candidate for sensing applications in the aqueous phase. In particular, the green emission of compound 1 could be quenched by the pesticide thiamethoxam (TMX), which was attributed to both the static and dynamic quenching processes based on an upward-curving Stern-Volmer plot. The quenching mechanism was speculatively attributed to the inner filter effect combined with the complex formation based on the electrostatic interaction of compound 1 and TMX, resulting in the promotion of the quenching efficiency. Finally, compound 1 was demonstrated to detect TMX in aqueous solution with rapid response and high selectivity.

A dual-emission ratiometric fluorescent sensor L/J-CDs with specific response to cetirizine hydrochloride in environmental water samples

A ratiometric fluorescent sensor L/J-CDs was constructed for the determination of cetirizine hydrochloride. In addition, visual detection of cetirizine hydrochloride was realized under ultraviolet lamp.

An intelligent readable and capture-antibody-independent lateral flow immunoassay based on Cu2-xSe nanocrystals for point-of-care detection of Escherichia coli O157:H7.

Escherichia coli (E. coli) O157:H7 is a common foodborne pathogen which can cause serious harm. It is particularly important to establish a simple and portable method to achieve on-site pathogen detection. In this study, a capture-antibody-independent lateral flow immunoassay (LFIA) was constructed based on Cu2-xSe nanocrystals (Cu2-xSe NCs) for rapid detection of E. coli O157:H7. Cu2-xSe NCs can not only be regarded as the "nano-antibody" for the recognition of E. coli O157:H7 through electrostatic adsorption, but also as nanozymes that show good peroxidase-like catalytic activity. The formed compound of E. coli O157:H7 and Cu2-xSe NCs would be captured by a detection antibody on the T line due to the specific recognition of the antibody and E. coli O157:H7. Then, Cu2-xSe NCs could catalyze the oxidation of TMB by H2O2 to generate oxTMB, thereby generating blue bands. Meanwhile, we developed a mobile app for rapid data analysis. Under the optimal reaction conditions, E. coli O157:H7 could be detected within 70 min. The detection limit of this method was 2.65 × 105 CFU mL-1 with good specificity and stability. Additionally, it could achieve on-site rapid detection of E. coli O157:H7 in environmental water samples, providing a promising biosensor for portable pathogen detection.

A colorimetric-aptamer-based assay for the determination of enrofloxacin through triggering the aggregation of gold nanoparticles.

Although enrofloxacin (ENR) is a widely used broad-spectrum antibiotic in veterinary medicine, its residues in animals can pose a risk to human health. Thus, we developed a new method for detecting ENR based on aptamers and AuNPs. In the absence of ENR, the aptamers attached to the surface of the AuNPs via electrostatic interactions to protect the AuNPs from NaCl, and the solution remained red. Conversely, the aptamer bonded with ENR, leading the aptamer to detach from the AuNP surface, and the color of the solution changed from red to blue. Based on this principle, ENR can be qualitatively detected by the naked eye and quantitatively detected by measuring the absorbance ratio at 650 nm and 530 nm. The experimental results showed a good linear relationship within the ENR concentration range of 0-400 nM, with a limit of detection (LOD) of 1.72 nM, which is satisfactory for detection in food safety. Additionally, this method has also been successfully applied to the detection of ENR in tap water, river water, milk, serum and urine, with good recovery rates and RSD values of less than 7%, indicating its great potential for ENR detection in environmental water samples. More importantly, the combination of this method with a smartphone platform provided great convenience for on-site and visual detection of ENR, offering promising applicability prospects.

Multi-class machine learning classification of PFAS in environmental water samples: a blinded test of performance on unknowns

A multi-class method was developed to identify PFAS origin based on chemical composition, and performance of the method was evaluated in a blinded test against unknowns. The method showed great promise in its ability to recognize sample origin.

Ethambutol inhibited the growth of acid-fast bacteria and enhanced the detection of Legionella in environmental water samples.

The growth of acid-fast bacteria often hinders the detection of Legionella in water samples on agar plates by the plate culture method. We studied whether anti-tubercular agents inhibit acid-fast bacteria growth on agar plates. First, the antimicrobial activities of isoniazid, ethionamide, and ethambutol were evaluated against Mycobacterium and Legionella. We found that ethambutol at ≥ 100 μg/mL completely inhibited Mycobacterium growth, but ethambutol at 1,000 μg/mL did not inhibit Legionella growth. Next, the effect of ethambutol dissolved in acid buffer was examined. Cell suspensions of L. pneumophila and Mycobacterium spp. were mixed, and ethambutol-acid buffer was added. After 5 min, mixtures were inoculated on GVPC agar plates and incubated at 36℃ for 6 d. We found that ethambutol inhibited Mycobacterium growth on agar plates, but the Legionella colonies recovered. The effect of ethambutol was also significant in the evaluation using bathwaters. Comparing 1,302 bathwaters, the addition of ethambutol reduced the detection rate of acid-fast bacteria from 30.6% to 0% and increased the detection rate of Legionella from 7.1% to 7.5%. Ethambutol, which selectively inhibited acid-fast bacteria growth, enhanced the detection of Legionella on agar plates and will contribute to improving the accuracy of Legionella testing by the plate culture method.

A novel ratiometric sensor for fluorimetric and visual dual-mode detection of Al3+ in environmental water based on the target-regulated formation of Eu MOFs.

Herein, a novel ratiometric sensor for fluorimetric and smartphone-assisted visual detection of Al3+ in environmental water was developed based on the target-regulated formation of Eu metal-organic frameworks (Eu MOFs). By employing 2-[4-(2-hydroxyethyl) piperazin-1-yl] ethanesulfonic acid (Hepes), Eu3+ and tetracycline (TC) as raw materials, Eu MOFs with red emission were facilely synthesized through the coordination of Eu3+ with Hepes and TC. However, upon the introduction of Al3+, a higher affinity of TC towards Al3+ resulted in the formation of a TC-Al3+ complex with green fluorescence and inhibited the generation of Eu MOFs. This led to an increase in green fluorescence and a decrease in red fluorescence accompanied by the fluorescence color of the solution changing from red to green under the illumination of the UV lamp. Thus, a ratiometric sensor for fluorimetric and the smartphone-assisted visual detection of Al3+ was established. The ratiometric sensor exhibited high sensitivity for Al3+ detection with a detection limit of 0.14 μM for fluorescence detection and 1.21 μM for visual detection. Additionally, the proposed strategy was successfully applied to detect Al3+ in the environmental water samples with satisfactory results, indicating great application prospects for environmental monitoring.

Detection of Surfactants using a Hydrophobic Natural Deep Eutectic Solvent and Smartphone

We report on the advantages of a green method to detect surfactants in environmental water samples. The approach is based on the use of a hydrophobic natural deep eutectic solvents...

Bio-derived solvent-based automated dispersive liquid–liquid microextraction for pretreatment of diamide insecticides in environmental water samples

The automatic dispersive liquid–liquid microextraction based on bio-derived solvents achieved great environmental greenness, high-throughput operation, and low human error compared to the present sample pretreatment methods for diamide insecticides.

Ternary magnetic silica–graphene oxide composite for remediation of textile dyes from aqueous environment and real samples

Abstract Inadequate wastewater treatment infrastructure is a substantial worldwide concern, with implications for both the environment and public health. Specifically, the discharge of industrial effluents containing organic pollutants such as dyes represents a significant challenge due to their hazardous characteristics. Among these dyes, Bromophenol Blue (BPB) and Malachite green (MG) are extensively utilized in the industrial sector, contributing to environmental deterioration. In the current study, ternary-magnetic-silicate–graphene oxide [Fe3O4@SiO2–GO] was synthesized using the co-precipitation method and applied for the treatment of wastewater containing BPB and MG dyes. The point of zero charge and surface area of the adsorbent was estimated to be 5.7 and 253.8 m2 g−1, respectively. Energy dispersive X-ray was performed and the presence of iron, silicon, carbon, and oxygen was confirmed. The XRD analysis of GO, Fe3O4, and ternary Fe3O4@SiO2–GO composites were also performed to confirm the crystallinity of the composite. The SEM analysis showed a rough morphology with sheet-like appearance. The ternary composite was then applied for the adsorption of BPB and MG dyes. The maximum adsorption capacity for BPB and MG was 97.35 mg/g and 92.63 mg/g at pH 3 and 5, respectively. The results of the kinetics analysis showed that the pseudo-second-order kinetics model best explained the adsorption data for MG dye while pseudo-first-order kinetics for the BPB dyes. While the data best fitted the Langmuir adsorption isotherm with R 2 values of 0.994 and 0.998 for BPB and MG, respectively. These results demonstrate that Fe3O4@SiO2–GO serves as a promising adsorbent for the efficient removal of Bromophenol Blue (BPB) and Malachite Green (MG) from environmental water samples. Additionally, this adsorbent is environmentally friendly and chemically benign, and it can be reused efficiently for up to five cycles.