The growing co-contamination of multiple metal ions seriously influences human health due to their synergistic and additive toxicological effects, whereas the rapid discrimination of multiple heavy ...metal ions in complex aquatic systems remains a major challenge. Herein, a high- throughput fluorescence sensor array was fabricated based on three gold nanoclusters (GSH-Au NCs, OVA-Au NCs, and BSA-Au NCs) for the direct identification and quantification of seven heavy metal ions (Pb2+, Fe3+, Cu2+, Co2+, Ag+, Hg2+ and As3+) from environmental waters without sample pretreatment other than filtration. At the detection system, three gold nanoclusters with various ligands possessed distinct binding capacities against metal ions and induced aggregation-induced fluorescence enhancement and quenching, resulting in a unique pattern of fluorescence variations. Meanwhile, integrated the collected fluorescence fingerprints with linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), a discrete database was obtained for the accurate recognition and sensitive detection of metal ions. Under the optimized conditions, the limit of detection (LOD) of the proposed fluorescence sensor array for metal ions detection at nM concentration level along with a satisfactory accuracy. Importantly, our study indicated that the fluorescence sensor array could be widely used as a general platform in environmental monitoring against multiple targets at low concentrations.
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•A fluorescence array sensor based on three gold nanoclusters was developed.•The array sensor could realize the identification of seven heavy metal ions.•A discrete database was constructed by integrating collected fluorescence fingerprints.•The proposed array achieved acceptable feasibility in real water samples detection.
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•The simple, fast and highly sensitive method for the determination of pinoxaden is based on fluorescence measurement of the Fe(III) based coordination complex of pinoxaden in the ...basic medium at 337 nm.•The signaling product is kinetically stable at room temperature having maximum fluorescence intensity with 0.2 µg mL−1 of Fe(III) at pH 9.•The complex shows a linear concentration range from 1 × 10−4,-1 × 10−3 µg mL−1 with a coefficient of determination R2 = 0.9917.•Density functional theory simulations shows stronger interaction energy (-1.11 eV) of Fe(III) ion with the pinoxaden.•The proposed approach is applied to quantify pinoxaden in the formulation and real agricultural and environmental samples and shows excellent recovery.
Keeping in view the toxicity of pesticides, development of analytical methods for their determination in environmental samples is the need of the day. Herein, a simple, fast and sensitive method for the determination of pinoxaden has been described. The kinetically stable, Fe(III) based complex of pinoxaden was formed at room temperature showing maximum fluorescence intensity at 337 nm with 0.2 µg mL−1 of Fe(III) at pH 9. The complex shows a linear response in the concentration range of 1 × 10−4-1 × 10−3 µg mL−1 with a coefficient of determination R2 = 0.9917, limit of detection and limit of quantification of 8.1 × 10−5 and 2.4 × 10−4 µg mL−1, respectively, and relative standard deviation and maximum matrix effect of 0.021% and 2.13%. Density functional theory simulations were used to understand the nature of Fe(III) based complex of pinoxaden. The larger negative interaction energy of −1.11 eV evince that the Fe(III) strongly coordinated with the N-atom shared by oxadiazopine ring and the pyrazole ring and the O atom of –CO group of side chain, which are consistent with the experimental results. Interference study shows that among the metal ions studied, only Cu(II), Co(II) and Pb(II) show reasonable interference effect. The proposed approach was applied to quantify pinoxaden in the formulation and real agricultural and environmental samples. The results indicate excellent recovery in the range of 89.44 ± 1.38–97.51 ± 2.62 % for wheat, barley, water and soil samples. In soil samples no residue was quantified while in the wheat and barley samples the residue found was below the maximum residue limit. Under optimized experimental conditions, the proposed method was found to be simple, fast, reasonably interference free and has trace level sensitivity. The method was found to be comparable and even superior to some literature methods for determination of pinoxaden in complex matrices.
•This part focuses on a)the advantages and disadvantages of solid-phase extraction (SPE) versus liquid–liquid extraction (LLE) andb)the controversies and contradictions found in the literature in ...i.the selection of sorbents andii.the optimization of conditioning and elution protocols and recoveries by SPE.•Moreover, the study reveals the lack of selectivity of most sorbents and SPE protocols.•We concluded that SPE procedures are yet to be systematized in the future.
Solid-phase extraction (SPE) is the most widely used method for the extraction, changing of solvents, clean-up, concentration and fractionation of organic compounds from several samples.
Here, we attempt to resolve the debates surrounding the suitability of sorbents for the extraction of several compounds, conditioning, washing and elution protocols, as well as the recoveries achieved by each SPE protocol. The lack of systematization and homogenization limits the efficient implementation of reliable SPE procedures.
This part focuses on the advantages and disadvantages of SPE versus liquid–liquid extraction (LLE), controversies and contradictions found in the literature with respect to the selection of sorbents, optimization of conditioning and elution protocols and recoveries by SPE. Moreover, it reveals the lack of selectivity of most sorbents and SPE protocols. It is divided into the following sections: applications of SPE, fractionation by SPE, outlook and conclusions.
This study evaluated sample processing methods and the presence of organic matter on detection of porcine epidemic diarrhea virus (PEDV) from environmental samples using real-time reverse ...transcriptase-polymerase chain reaction (qRT-PCR). Steel coupons were inoculated with PEDV and different types of organic material contamination. Surface samples were collected and processed in one of four ways: none, centrifugation, syringe filtration, or combination of centrifugation and syringe filtration, then submitted for PEDV qRT-PCR. There was a surface inoculation type by processing method interaction (P < .001) that impacted the sample cycle threshold value. Centrifugation resulted in the most consistent detection of PEDV RNA.
Solid-phase extraction (SPE) is the most widely used method for the extraction, changing of solvents, cleanup, concentration, and fractionation of organic compounds from a number of samples. This ...procedure is also very useful for desalting proteins and sugar samples. However, most SPE procedures are still poorly developed, with little consideration to the physics involved in the process and are described as largely empirical, labor-intensive, and time-consuming trial-and-error processes, without much systematization.
The objective of this study is to propose a number of contradictions, disagreements, failings, and shortcomings of the SPE procedures found elsewhere. The different arguments introduced in this study attempt to challenge the suitability of this procedure, particularly when it is conducted in the traditional manner (under gravity and at a high flow rate).
The first part of this study focuses on describing the state-of-the-art in SPE and its physical fundamentals.
In recent years, the usage of magnetic sorbents in sample preparation and contaminants removal techniques has received considerable attention as they can be easily recovered using an external ...magnetic field. This ability reduces sample treatment time and simplifies the procedure. In this review, the most recent and outstanding applications (2017–2021) of magnetic sorbents for preconcentration and removal purposes is reviewed and discussed. This review firstly, discusses preparation, advantages, limitations and possible interactions of different types of magnetic sorbents briefly (nanoparticles, nanocomposites, sponges, foams, beads and hydrogels) and also views on how to choose the appropriate sorbent based on the intended application. Secondly, the role of magnetic sorbents in the common sample preparation techniques such as solid phase extraction, solid phase microextraction, stir bar sorptive extraction and liquid phase microextraction are also investigated and discussed. In conclusion, remarkable features and future trends are commented.
•Different types of magnetic sorbents were described.•Synthesis, distinct features and possible interactions of magnetic sorbents were discussed.•The role of the magnetic sorbents in improving samples preparation techniques was discussed.•Recent applications of magnetic sorbents in separation techniques were discussed.•Attractive trends in the field of magnetic sorbents were highlighted.
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•A novel method for biosynthesized silver nanoparticles based on bitter orange bloom extract was presented.•AgNPs was subsequently utilized to detect and determine cyanide ions.•The ...developed colorimetric sensor can detect cyanide ions with good selectivity in aqueous solutions.
Developing new methods for detecting and determining toxic anions is an essential parameter from waste sources for industrial and environmental scientists. This study presented, a new process for the biosynthesis of silver nanoparticles (AgNPs) based on the bitter orange bloom extract and its potential as a highly selective and sensitive chemosensor for detecting and quantifying cyanide ions. These biosynthesized AgNPs have a sharp and intense surface plasmon resonance (SPR) peak around 405 nm. AgNPs with a yellow color can be changed to colorless in the presence of a certain concentration of cyanide ions due to forming a new adduct between AgNPs and cyanide ions. Hence, the SPR intensity of AgNPs decreases, and the color of the solution becomes colorless. The sensor response to cyanide ions was linear in the concentration range of 49.7 to 1208.8 nM, and the detection limit was equal to 7.9 nM. As an applicable alternative, this assay is highly capable of qualitative and quantitative measurements of cyanide ions in the waste and toxic samples.
One of the major methods to identify microbial community composition, to unravel microbial population dynamics, and to explore microbial diversity in environmental samples is high-throughput DNA- or ...RNA-based 16S rRNA (gene) amplicon sequencing in combination with bioinformatics analyses. However, focusing on environmental samples from contrasting habitats, it was not systematically evaluated (i) which analysis methods provide results that reflect reality most accurately, (ii) how the interpretations of microbial community studies are biased by different analysis methods and (iii) if the most optimal analysis workflow can be implemented in an easy-to-use pipeline. Here, we compared the performance of 16S rRNA (gene) amplicon sequencing analysis tools (i.e., Mothur, QIIME1, QIIME2, and MEGAN) using three mock datasets with known microbial community composition that differed in sequencing quality, species number and abundance distribution (i.e., even or uneven), and phylogenetic diversity (i.e., closely related or well-separated amplicon sequences). Our results showed that QIIME2 outcompeted all other investigated tools in sequence recovery (>10 times fewer false positives), taxonomic assignments (>22% better F-score) and diversity estimates (>5% better assessment), suggesting that this approach is able to reflect the in situ microbial community most accurately. Further analysis of 24 environmental datasets obtained from four contrasting terrestrial and freshwater sites revealed dramatic differences in the resulting microbial community composition for all pipelines at genus level. For instance, at the investigated river water sites Sphaerotilus was only reported when using QIIME1 (8% abundance) and Agitococcus with QIIME1 or QIIME2 (2 or 3% abundance, respectively), but both genera remained undetected when analyzed with Mothur or MEGAN. Since these abundant taxa probably have implications for important biogeochemical cycles (e.g., nitrate and sulfate reduction) at these sites, their detection and semi-quantitative enumeration is crucial for valid interpretations. A high-performance computing conformant workflow was constructed to allow FAIR (Findable, Accessible, Interoperable, and Re-usable) 16S rRNA (gene) amplicon sequence analysis starting from raw sequence files, using the most optimal methods identified in our study. Our presented workflow should be considered for future studies, thereby facilitating the analysis of high-throughput 16S rRNA (gene) sequencing data substantially, while maximizing reliability and confidence in microbial community data analysis.
Cyclosporiasis is an emerging disease that is ubiquitous in humans and other animals worldwide. Cyclospora cayetanensis , which is distributed in the tropical and subtropical regions, and endemic in ...several developing countries, is the only species of Cyclospora resulting in cyclosporiasis in humans. The main objective of this review was to summarize the prevalence of Cyclospora in humans, animals, and environmental samples in Nepal. The overall prevalence of Cyclospora in humans has been reported to be 10.3% (3,785/36,570), including 3.6% (60/1,640) among HIV immunocompromised cases, 2.1% (210/9,733) among children, and 13.9% (3,515/25,197) in humans of all age categories, while the prevalence was calculated to be 2.9% (29/983) and 10.5% (9/85) in domestic and wild animals, respectively. The molecular characterization data on Cyclospora as related to Nepal is limited to a very few positive isolates from humans, dogs, chickens, and monkeys. Exposure to sewage water and contaminated fresh food items, and the presence of domestic animals appear to have been associated to an outbreak of Cyclospora in humans. Considering Cyclospora spp. as the etiologic agent for diarrhoea, a comprehensive, wider scale molecular epidemiologic study in humans, animals, and environmental samples is warranted to elucidate the exact distribution loci and probable outbreak of cyclosporiasis in Nepal.
The discovery of magnetic nanomaterials has bestowed a tremendous impact on the improvement and development of many disciplines, including analytical chemistry because their special properties make ...them very suitable for wide applications. Owing to their superparamagnetism, selective adsorption ability as well as easy separation and surface modification, these unique nanomaterials unfold excellent performance in extracting and enriching a variety of target analytes. When coupled with gas chromatography-mass spectrometry, high-performance liquid chromatography-mass spectrometry and other instrumental analysis techniques, it will enable the detection and identification of trace pollutants in a single and rapid analysis. This review article gives an insight into recent advances in the synthesis, modification and application of magnetic nanomaterials for the preconcentration of environmental pollutants.
•Meta-analysis and systematic review of sample preparation techniques are provided.•Comparison of analytical methods for various environmental samples was carried out.•The prospects of magnetic nanomaterials in sample pretreatment are evaluated.
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