Detection Of Pollutants Research Articles

Plausible Avenues and Applications of Bioformulations from Symbiotic Culture of Bacteria and Yeast

Microbial cellulose, especially the bacterial cellulose produced by symbiotic co-cultures of acetic acid bacteria and yeast (SCOBY) that exists in a mutualistic interaction opens plausible strategies in the field of food as well as sustainable regenerative eco-system and waste management. Cultivated on sweetened black tea, the mutually proliferating bacteria (Acetobacter xylinum, A. xylinoides, and Bacterium gluconicum) and yeast strains (Schizosaccharomyces pombe, Saccharomycodes ludwigii and Saccharomyces cerevisiae) produces a fermented liquor along with the floating bacterial cellulosic pellicle called as Kombucha. This review explores the possible applications of kombucha SCOBY to use bacterial cellulose-based engineered living materials, commercial superabsorbent spheres by various marketing ventures like food, pharmaceutics, biomedical applications for bio-sensing and bio-catalysis, crop biostimulants, biocontrol agents in the management of plant and animal illnesses, post-harvest management in crops, water purification, pollutant detection, environmental biotechnology, and production of SCOBY from alternative substrates and agrarian waste management. The plausible use of bacterial cellulose hydrogels in dryland agriculture for their exceptional water-absorbing capability, eco-friendly nature, capacity to break down naturally, and compatibility with other living organisms is also elaborated in this paper. Furthermore, diverse microbial species to enhance the variety and functional properties of SCOBY, health benefits and its influence on human welfare is vividly discussed in the paper. The very in-depth study on the uses of SCOBY also paves way for the research exploration of this under-utilized microbial boon in food and farm sector for circular based regenerative agriculture in near future.

Facile coupling of plasmonic Au-NPs on ZnS NFs as a robust SERS substrate for toluidine blue detection and degradation

BackgroundThe robustness and sensitivity of the surface-enhanced Raman spectroscopy (SERS) technique heavily relies on the development of SERS active materials. A hybrid of semiconductor and plasmonic metals is highly effective as a SERS substrate, which enables the trace level detection of various organic pollutants. ResultsThis approach demonstrates the photodeposition of plasmonic gold nanoparticles (Au-NPs) on the surface of semiconductor-zinc sulfide nanoflowers (ZnS NFs), grown via the hydrothermal route. The synergistic contribution of the charge-transfer phenomenon and localized surface plasmon resonance of the Au-NPs/ZnS NFs makes it an ideal SERS substrate for the detection of organic pollutants, toluidine blue (TB). The proposed material has a high SERS enhancement factor (109), low limit of detection (10−11 M), good reproducibility, selectivity and strong anti-interference ability. Furthermore, the practicability of the Au-NPs/ZnS NFs is explored in real-time water samples, which are obtained with the satisfactory recovery rates. Additionally, the UVC light illumination on the Au-NPs/ZnS NFs has efficiently degraded TB within a time period of 150 min. Significance and noveltyThese finding demonstrate the significance of the proposed Au-NPs/ZnS NFs for SERS based detection and degradation of organic pollutants in real-time samples, highlighting their potential in monitoring and treating water pollutants in wastewater.

Phosphomolybdates for Dual-Mode Photoelectrochemical Sensing toward Trace Chromium(VI) and Tetracycline.

Highly sensitive photoelectrochemical (PEC) sensors for trace carcinogens, such as heavy metal chromium(VI) [Cr(VI)] and antibiotic tetracycline (TC) are crucial. Herein, by integration of photoactive and redox phosphomolybdates with conjugated organic components, types of dual-mode PEC sensors were synthesized for sensing trace Cr(VI) and TC pollutants, with formulas of (H2bimb)2[Co2(bimb)1.5][Co(H2O)4][Co(P4Mo6O31H6)2]·6H2O (1), (H2bib)2[Co(H2O)3][Co2(H2O)5][Co(P4Mo6O31H6)2]·9H2O (2), and (H2bib)6[Co(Hbib)2(H2O)5][Co(P4Mo6O31H7)2]2·15H2O (3), where bimb represents 1,4-bis(1-imidazolyl)benzene and bib is 4,4'-bis(imidazolyl)bibphenyl. Hybrid 1 consisted of a three-dimensional framework structure constructed by Co{P4Mo6}2 clusters and one-dimensional (1D) {Co-bimb} chains, hybrid 2 exhibited 1D Co ion-bridged Co{P4Mo6}2 chains hydrogen-bonding with [H2bib]2+ cations, and hybrid 3 showed a discrete hybrid structure built upon a Co{P4Mo6}2 cluster modified by the {Co-bib} unit. Hybrids 1-3 displayed wide spectral absorption and excellent electrochemical redox properties, enabling dual-mode PEC responses to Cr(VI) reduction and TC oxidation. For Cr(VI) detection, hybrids 1-3 exhibited high sensitivities of 364.40, 225.72, and 124.29 μA·μM-1 as well as "nM" level detection limits (LODs) of 4.9, 10.0, and 11.0 nM, respectively. For TC detection, the sensitivities of hybrids 1-3 were 494.72, 308.78, and 174.03 μA·μM-1 and the LODs were 5.2, 6.1, and 12.9 nM, respectively. This research offers significant insights into designing efficient PEC sensors for the detection of environmental pollutants.

Dual COF functionalized magnetic MXene composite for enhancing magnetic solid phase extraction of thiophene compounds from oilfield produced waters prior to GC-MS/MS analysis

In this study, a novel COFTABT@COFTATp modified magnetic MXene composite (CoFe2O4 @Ti3C2 @COFTABT@COFTATp) was synthesized by Schiff base reaction and irre-versible enol-keto tautomerization, and employed to establish a sensitive monitoring method for six thiophene compounds in oilfield produced water samples based on magnetic solid-phase extraction (MSPE) prior to gas chromatography coupled with a triple quadruple mass spectrometer (GC-MS/MS). The designed magnetic materials exhibited unexpected enrichment ability to target thiophene compounds and achieved good extraction efficiencies ranging from 83 % to 98 %. The developed MSPE/GC-MS/MS method exhibited good linearity in the range of 0.001–100 μg L−1, and obtained lower limits of detection ranging from 0.39 to 1.9 ng L−1. The spiked recoveries of thiophene compounds obtained in three oilfield produced water samples were over the range of 96.26 %−99.54 % with relative standard deviations (RSDs) less than 3.7 %. Notably, benzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene were detected in three oilfield-produced water samples. Furthermore, the material still kept favorable stability after six recycling experiments. The adsorption kinetics, adsorption isotherms as well as adsorption thermodynamics of thiophene compounds were investigated in detail to provide insight into the mechanisms. Overall, the present work contributed a promising strategy for designing and synthesizing new functionalized materials for the enrichment and detection of typical pollutants in the environment.

CODS: Carbon Monoxide Pollution Detection and Monitoring System Based on The Internet of Things Towards Urban Health Enhancement

CODS: Carbon Monoxide Pollution Detection and Monitoring System Based on The Internet of Things Towards Urban Health Enhancement

Shell thickness-dependent Au@Ag nanoparticles for surface-enhanced Raman scattering detection of pollutants

A series of Au@Ag core–shell nanocomposites with varying Ag shell thickness were prepared as potential SERS substrates via chemical reduction method. Rhodamine 6G, crystal violet, and thiram were selected as probes for SERS substrate optimization and sensitivity testing of nanocomposites. According to the results, the Au surface was uniformly coated with a ∼3–12 nm thick Ag layer, exhibiting the even particle size distribution. The above nanocomposites demonstrated an extremely high detection limit for Rhodamine 6G (up to 10−11 M) within a sensitivity range of 10−5 to 10−11 M. At the same time, the detection limits for crystal violet and thiram were 10−10 M and 10−9 M, respectively. Moreover, the SERS performance remained basically unchanged after 30-day storage, indicating good stability and uniformity of Au@Ag substrates. Thus, the proposed Au@Ag nanocomposites have a great application potential for the detection of low-concentration pollutants in the environment along with the prolonged in-use stability.

A homobimetallic nickel(II) complex for discriminative chromogenic recognition of aqueous cyanide and silver(I) from medicinal products: Role of end-on thiocyanate bridging

Herein, a homobimetallic azomethine-functionalized nickel(II) complex, [Ni2L2(van)(μ1,1-NCS)] (AMR-1, where L = 2-[(2-Hydroxy-1,1-dimethyl-ethylimino)-methyl]-6-methoxyphenol, molecular weight = 788.20 (found)) has been judiciously synthesized with N-coordinated end-on thiocyanate. AMR-1 exhibited promising chromogenic variation from pale green to colourless with hypochromic shifting in the visible region in the presence of silver(I). Herein, the exposed sulfur site of the co-ligand acts as chemodosimetric recognition site for highly selective detection of a soft metal pollutant, silver ion (Ag+) with the limit of detection (LOD) of 0.37 ppm. Along with this, aqueous cyanide (CN−) recognition was accomplished in a mutually independent way with distinct chromogenic variation from pale green to yellowish color within ∼5 s. This led to the LOD of 0.46 ppm, which is much lower than the safe limit, set by the World Health Organization (WHO). The stability constant value for cyanide interaction with AMR-1 is obtained to be 1.49 × 103 M−1 as per 1:1 binding stoichiometry. Experimental findings, obtained from UV–Vis, HR-MS, FT-IR, and 1H NMR spectroscopic studies in conjugation with the decreased HOMO-LUMO energy gap from 3.40 eV to 2.07 eV, obtained from density functional theory studies, support the mechanistic pathway of interaction. Implementing molecular logic platforms benefits from fabricating three-input-two-output logic circuits by imitating variable spectroscopic outcomes. Real-time multifarious applications of AMR-1 have been accomplished with paper strip-based solid-state assay and recognition of the target-specific analytes from targeted medicinal specimens and from both cyanogenic as well as non-cyanogenic food sources. To the best of our knowledge, this is probably the first nickel(II) complex derived sensory receptor that is effectually implemented towards recognition of another metal ion, silver (I) along with CN− from aqueous as well as from real specimens.

Accumulation of Parabens, Their Metabolites, and Halogenated Byproducts in Migratory Birds of Prey: A Comparative Study in Texas and North Carolina, USA.

Parabens are alkyl esters of p-hydroxybenzoic acid that are commonly used as preservatives in personal care products such as cosmetics. Recent studies have revealed the presence of parabens in surface and tap water because of their use as disinfection products; however, little is known about their occurrence in biological samples and their bioaccumulation potential, particularly in raptor birds known as sentinels for pollutant detection. We examined the occurrence and tissue distribution of parabens, their metabolites, and halogenated byproducts in the liver, kidney, brain, and muscle of birds of prey from Texas and North Carolina (USA). Methylparaben (MeP), propylparaben (PrP), and butylparaben (BuP) were detected in more than 50% of all tissues examined, with the kidney exhibiting the highest concentration of MeP (0.65-6.84 ng/g wet wt). Para-hydroxybenzoic acid (PHBA), a primary metabolite, had the highest detection frequency (>50%) and a high accumulation range in the liver, of 4.64 to 12.55 ng/g. The chlorinated compounds chloromethylparaben and chloroethylparaben were found in over half of the tissues, of which dichloromethylparaben (2.20-3.99 ng/g) and dichloroethylparaben (1.01-5.95 ng/g) in the kidney exhibited the highest concentrations. The dibrominated derivatives dibromideethylparaben (Br2EtP) was detected in more than 50% of samples, particularly in muscle and brain. Concentrations in the range of 0.14 to 17.38 ng/g of Br2EtP were detected in the kidney. Dibromidepropylparaben (Br2PrP) was not frequently detected, but concentrations ranged from 0.09 to 21.70 ng/g in muscle. The accumulations of total amounts (sum) of parent parabens (∑P), metabolites (∑M), and halogenated byproducts (∑H) in different species were not significantly different, but their distribution in tissues differed among the species. Positive correlations were observed among MeP, PrP, BuP, and PHBA in the liver, suggesting similar origins and metabolic pathways. Environ Toxicol Chem 2024;43:2365-2376. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Pore-networked membrane using linked metal-organic polyhedra for trace-level pollutant removal and detection in environmental water

The wide presence of pharmaceuticals and personal care products (PPCPs) in water is a major pollution concern even at the part per billion level, which urges their detection and removal. Current research emphasizes the use of microporous materials as adsorbents for pollutant removal but demonstrates the performance at a higher concentration than realistic environmental water due to the absence of efficient detection methods that can be coupled with the removal process. Here we report a pore-networked membrane (PNM) that can simultaneously remove and detect targeted trace-level PPCPs. These PNMs are designed by interconnecting adsorbents within polymer matrices, forming continuous, tunable porous networks that are accessible for PPCPs, thereby offering high selectivity and adsorption capacity. Evaluations across water samples containing 13 pollutants demonstrate the capability of PNMs to selectively adsorb PPCPs for removal and subsequently release them into analysis solution for detection, positioning their promising use in real water treatment workflow.

Polyoxometalate-based nanozyme with laccase-mimicking activity for kanamycin detection based on colorimetric assay.

As a kind of aminoglycoside antibiotics, kanamycin (KAN) is widely applied to animal husbandry and aquaculture. However, the abuse of KAN causes the large-scale discharge of it into rivers, lakes and groundwater, which threatens environmental safety and human health. Therefore, it is imperative to develop a method that is applicable to detect KAN in an efficient and accurate way. The colorimetric method based on enzymes provides a feasible solution for the detection of organic pollutants. However, the extensive application of natural enzymes is constrained by high cost and low stability. Herein, a polyoxometalate-based nanozyme, namely [H7SiW9V3O40(DPA)3]·4H2O (SiW9V3/DPA) (DPA = dipyridylamine), is synthesized. As a low-cost nanozyme with high stability compared to natural enzymes, SiW9V3/DPA performs well in laccase-mimicking activity. It can be used to induce chromogenic reaction between 2,4-dichlorophenol (2,4-DP) and 4-aminoantipyrine (4-AP), which generates red products. With the addition of KAN, the color fades. That is to say, KAN can be detected with colorimetric assay in the concentration range 0.1 to 100μM with high selectivity and low limit of detection (LOD) of 6.28μM.Moreover, SiW9V3/DPA is applied to KAN detection in lakeand riverwater and milk with satisfactory results. To sum up, polyoxometalate-based nanozyme is expected to provide a promising solution to the detection of organic pollutants in the aquatic environment.

Visual detection of aldehyde gases using a silver-loaded paper-based colorimetric sensor array

The small molecule aldehydes are volatile organic compounds (VOCs), possessing cytotoxicity and carcinogenicity. Long-term exposure can pose a serious threat to human health. Based on an in-situ reduction colorimetric method to generate silver nanoparticles and induce colorimetric response, we proposed a silver-loaded paper-based colorimetric sensor array for visually detecting and differentiating five relatively common trace small molecule aldehyde gases. The silver ions are immobilized onto a porous filter paper and stabilized by complexing agents of branched polyethyleneimine, ethylenediamine, and 1,6-diaminohexane, respectively. The as-fabricated sensor array expresses remarkable stability and capacity to resist humidity. The qualitative analysis reveals that the sensor array has excellent selectivity for aldehyde gases and displays remarkable anti-interference ability. The quantitative analysis indicates that the sensor array exhibits superior sensitivity for five aldehyde gases, with limits of detection (LODs) of 9.0 ppb for formaldehyde (FA), 3.1 ppm for acetaldehyde (AA), 3.5 ppm for propionaldehyde (PA), 23.8 ppb for glutaric dialdehyde (GD), and 71.5 ppb for hydroxy formaldehyde (HF), respectively. Importantly, these LODs are all comfortably below their respective permissible exposure limits. A unique colorimetric response fingerprint is observed for each analyte. Standard chemometric methods illustrate that the sensor array has excellent clustering capability for these aldehyde gases. Additionally, the sensor array's response is irreversible and possesses outstanding performance for cumulative monitoring. This colorimetric sensor array based on silver ions reduced to silver nanoparticles offers a novel detection method for the continuous, ultrasensitive, and visual detection of trace airborne pollutants.

Legacy and novel contaminants in surface sediments of Admiralty Bay, Antarctica Peninsula

Despite being one of the most remote areas on the planet, the Antarctic continent is subject to anthropogenic influences. The presence of various groups of contaminants, including persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs), has been documented in the region over the past decades. However, a significant knowledge gap remains regarding the detection of new pollutants, such as emerging contaminants (ECs), in Antarctic coastal environments. This study analyzed the occurrence and levels of selected POPs, PAHs, ECs in surface sediments from Admiralty Bay, Antarctica Peninsula. Non-target screening was employed to identify potential novel contaminants in the region. Samples (n = 17) were extracted using an accelerated solvent extraction (ASE) system and instrumental analyses were performed using gas chromatography coupled to a triple-quadrupole mass spectrometer (GC/MS-MS). Regarding regulated contaminants, concentrations of Σ5PCBs ranged from <LOD to 0.5 ng g−1, while Σ16PAHs ranged from 2.6 to 617.4 ng g−1. These compounds were predominant in the Martel inlet, suggesting influences of local input sources, especially for PAHs. ECs were detected in some sites of the Ezcurra and Martel inlets, especially nearby the Brazilian and Polish research stations. The UV filters homosalate (0.3 to 251.3 ng g−1) and octocrylene (0.7 to 93.8 ng g−1) were the most abundant EC, followed by TPP (0.1 to 87.4 ng g−1) and galaxolide (0.2 to 55.0 ng g−1). Applying non-target analysis, phthalates, and the fragrance OTNE (octahydro-tetramethyl-naphthalenyl-ethanone) were identified for the first time in Antarctic sediments. The data highlights the contribution of human activities in the region, possibly through wastewater effluents. This study provides data on the current levels of PAHs and POPs in the region, which are steadily decreasing over the years.

An Integration Method of UML Diagrams and Arduino UNO for Developing Water Pollution Detection System

Despite the scientific and health development in the world, water pollution can pose a threat to human health, whether the pollutants are biological or chemical. In addition, traditional methods of water pollution detecting require high costs, and take time. Due to the importance of water for human life, drinking, irrigation, or for use in industry etc. Thus, reliable methods for water contamination detecting are a crucial issue.This paper aims to propose an integration method of UML diagrams and Arduino UNO microcontroller for developing water pollution detection system. The proposed method consists of three phases, which are system’s design, system's schematic and system’s architecture. It uses use case diagram and sequence diagram. In addition, the system design consisting of a microcontroller and multiple connected sensors for water pollutant detection, namely pH, turbidity, dissolved solids, temperature, oxidation reduction potential and electrical conductivity. The result of this paper is the production an automatic water pollutant detection prototype using Arduino and UML diagrams to display the water pollution parameters. The variables pH, turbidity, dissolved solids, temperature, oxidation reduction potential and electrical conductivity were chosen because they are the physical and chemical parameters that most influence water quality. The proposed system is characterized by measuring the water quality in real time, low cost and its data is accurate and fast.

Ten years of oil pollution detection in the Eastern Mediterranean shipping lanes opposite the Egyptian coast using remote sensing techniques

The Eastern Mediterranean region, a vital conduit for global maritime trade, faces significant environmental challenges due to marine pollution, particularly from oil spills. This is the first study covering the long period of comprehensive monitoring of oil pollution using the full mission of Sentinel-1 Synthetic Aperture Radar (SAR) data in the Mediterranean Sea, so this research aims to detect and analyze comprehensively the occurrence of oil spills in the Eastern Mediterranean over a decade (2014–2023). This study focuses on identifying geographical distribution patterns, proximity to shorelines, frequency across maritime zones, and potential sources of these spills, especially around major ports and maritime routes. This study utilizes SAR data from the Sentinel-1 satellite. The methodology included automated detection algorithms within the Sentinel application platform (SNAP) and integration with GIS mapping to study oil spill patterns and characteristics. Over 1000 Sentinel-1 scenes were investigated in the northern Mediterranean waters off the coast of Egypt, to detect and analyze 355 oil spill events with a total impacted area of more than 6000 km2. The analysis of temporal spill distribution reveals significant fluctuations from year to year. Within the entire timeline of the study, 2017 had the largest spatial areas covering one thousand square kilometers. In contrast, the single largest spill recorded during the study period occurred in 2020, covering 198.73 square kilometers. The results identified a non-uniform distribution of oil spills and primarily exhibiting elongated patterns aligned with the navigation routes. The distinct increase of oil spill incidents was within the Exclusive Economic Zone (EEZ), obviously drifted to the coastline and around major ports. The study emphasizes the critical role of remote sensing technologies in addressing environmental challenges caused by the maritime transport sector, advocating for enhanced monitoring and regulatory enforcement to protect marine ecosystems and support sustainable naval activities. The findings highlight the urgent need for targeted continuous monitoring and rapid response strategies in high-traffic maritime areas, particularly around the EEZ and major ports.

Microfluidic devices to monitor water pollution

Microfluidic devices offer a promising future for monitoring water pollution caused by heavy metals, especially as the world continues to develop and the dangers of pollutants increases. This highlights the importance of developing these devices. These devices operate within the dynamics of fluids and quantify pollutants with numerous advantages, such as high sensitivity and specificity. They can also be integrated with mini sensors alongside analytical techniques. This study provides a brief overview of the types of microfluidic devices, such as polydimethylsiloxane (PDMS) and microfluidic paper-based (µPADs), and their application in pollutant detection. Microfluidic devices are associated with analytical methods such as spectrometric, colorimetric, and electrochemical techniques. Their importance lies in their simple manufacturing, rapid detection capabilities, and portability. Additionally, these devices can be updated to meet current needs in water pollution detection by integrating various analytical methods and enhancing these methods with programs that provide on-site results. There for microfluidics are currently of great importance due to their ease of manufacturing and applicability to various analytical methods, particularly for detecting pollutants in water. Many studies highlight the extraordinary potential of paper-based devices, which are the easiest to manufacture among all microfluidic devices and are not subject to stringent engineering and physical constraints. Most importantly, they can utilize colorimetric detection methods, providing instant results visible to the naked eye. This study demonstrates these advantages and suggests the potential for expanding their applications in medical, environmental, and biological fields.

Innovative Approaches for Microplastic Pollution Detection and Remediation in Aquatic Ecosystems

Microplastic pollution in aquatic ecosystems is a pressing environmental issue, posing significant threats to marine life and human health. Traditional detection and remediation methods are often inadequate, necessitating the development of innovative approaches. This research aims to explore and evaluate novel techniques for detecting and mitigating microplastics in aquatic environments. The study investigates advanced detection technologies, including spectroscopy and sensor-based methods, that offer higher accuracy and efficiency compared to conventional approaches. Additionally, it explores innovative remediation techniques such as bioremediation and the use of advanced filtration systems. Field and laboratory experiments were conducted to test the effectiveness of these methods in various aquatic settings. The results indicate that these innovative approaches significantly enhance the detection and removal of microplastics, demonstrating superior performance over traditional methods. This research provides critical insights into the potential of advanced technologies in addressing microplastic pollution, highlighting their applicability and benefits for environmental conservation. By integrating these innovative solutions, we can better safeguard aquatic ecosystems and promote sustainable environmental practices.

Ag-La(OH)3@Dy2O3 hybrid composite modified laser-induced graphene surface for simultaneous electrochemical detection of bisphenol A and tartrazine

Laser-induced graphene (LIG), created through CO2 laser irradiation of polyimide film (PI) substrates, has emerged as a versatile and promising material in numerous fields. However, despite its potential, a comprehensive exploration of LIG’s surface structure and reactivity remains absent in the literature, which is crucial for advancing its applications in electrochemical and electroanalytical fields. In this study, we developed and examined the interfacial structure and electronic behavior of an Ag-La(OH)3@Dy2O3 hybrid composite-modified LIG system as a model. We employed scanning electrochemical microscopy (SECM) to investigate these properties, extending our analysis to the simultaneous detection of organic pollutants, such as bisphenol A (BPA) and tartrazine (TRZ), in real samples. Compared to previous LIG production techniques, the LIG-modified electrode demonstrated a high electron transfer rate at the interface. The tailored LIG substrate showed excellent electrochemical activity towards electrochemical oxidation and simultaneous electroanalytical applications for BPA and TRZ with low detection limits (BPA: 9.2 nM, TRZ: 0.96 nM) in neutral physiological conditions. As a proof of concept, an extension to the real-time application of simultaneous monitoring of BPA and TRZ in various food samples was successfully demonstrated.

Sesame Detection in Food Using DNA-Functionalized Gold Nanoparticles: A Sensitive, Rapid, and Cost-Effective Colorimetric Approach.

Food safety control is a key issue in the food and agriculture industries. For such purposes, developing miniaturized analytical methods is critical for enabling the rapid and sensitive detection of food supplements, allergens, and pollutants. Here, a novel bioanalytical methodology based on DNA-functionalized gold nanoparticles (AuNPs) and colorimetric detection was developed to detect the presence of sesame (a major allergen) through sesame seed DNA as a target, in food samples. The presence of sesame DNA induces controlled nanoparticle aggregation/desegregation, resulting in a color change (from blue to red) proportional to sesame DNA concentration. The incorporation of multicomponent nucleic acid enzymes (MNAzymes) in this strategy has been carried out to perform an isothermal signal amplification strategy to improve the sensitivity of detection. Also, open-source software for color analysis was used to ensure an unbiased visual color-change detection, enhancing detection accuracy and sensitivity and opening the possibility of performing a simple and decentralized analyte detection. The method successfully detected the presence of sesame DNA in sesame seed, sesame oil, olive oil, and sunflower oil. In brief, the developed approach constitutes a simple and affordable alternative to perform a highly sensitive detection of DNA in food without complex methodologies or the requirement of expensive instrumentation.

Bi-functional NiFe2O4/SrTiO3 S-scheme heterojunction for eminent performance photocatalytic treatment of sewage effluent and electrochemical hydrazine determination

Devising of materials that afforded dual applicability in decontamination and pollutant detection were still a towering challenge owing to the increasing flux of discharge toxic contaminants over the years. Herein, the NiFe2O4 nanoparticles-loaded on cube-like SrTiO3 (NiFe2O4/SrTiO3) composite was fabricated by a two-step hydrothermal approach providing remarkable photocatalytic treatment and electrochemical sensing of noxious pollutants in wastewater. The material traits of the fabricated composite were scrutinized by myriad characterization approaches. The NiFe2O4/SrTiO3 hybrid material demonstrated high surface area of 19.81 m2/g, adequate band gap energy of 2.75 eV, and prominent photoluminescence characteristics. In the presence of visible light, the NiFe2O4/SrTiO3 exhibited profound photocatalysis capability to eliminate sewage effluent-bearing chlortetracycline hydrochloride (CTCH) with 88.6% COD removal in 120 min, outperforming other pure materials. Meanwhile, the toxicity examination of effluent, the possible degradation pathway of CTCH and the proposed photocatalysis mechanism were also divulged. More importantly, the glassy carbon electrode was modified with synergized NiFe2O4/SrTiO3 (NiFe2O4/SrTiO3−GCE) was adopted for the precise quantification of Hydrazine (Hz). The NiFe2O4/SrTiO3−GCE obeyed first-order response for the Hz detection within the range of 1–10 mM: cyclic voltametric: limit of detection (LOD) of 0.119 μM with sensitivity of 18.9 μA μM−1 cm−2, and linear sweep voltametric: LOD of 0.222 μM with a sensitivity of 12.05 μA μM−1 cm−2. The stability and interference of modified electrode were also inspected. This work furnished valuable insights to yield a composite with the prominent S-scheme heterojunction system for quenching of charge carrier recombination and consequently contributing to the future realization into the domains of environmental clean-up and toxic chemical detection.

Facile synthesis of Ag NPs@MgO nanosheets for quantitative SERS-based detection and removal of hazardous organic pollutants

Surface-enhanced Raman spectroscopy (SERS) is a highly precise and non-invasive analytical method known for its ability to detect vibrational signatures of minute analytes with exceptional sensitivity. However, the efficacy of SERS is subject to substrate properties, and current methodologies face challenges in attaining consistent, replicable, and stable substrates to regulate plasma hot spots across a wide spectral range. This study introduces a straightforward and economical approach that incorporates monodispersed silver nanoparticles onto 2-D porous magnesium oxide nanosheets (Ag@MgO-NSs) through an in-situ process. The resulting nanocomposite, Ag@MgO-NSs, demonstrates substantial SERS enhancement owing to its distinctive plasmonic resonance. The effectiveness of this nanocomposite is exemplified by depositing diverse environmental pollutants as analytes, such as antibiotic ciprofloxacin (CIP), organic dyes like rhodamine 6G (R6G) and methylene blue (MB), and nitrogen-rich pollutant like melamine (MLN), onto the proposed substrate. The proposed nanocomposite features a 2-D porous structure, resulting in a larger surface area and consequently providing numerous adsorption sites for analytes. Moreover, engineering the active sites of the nanocomposite results in a higher number of hotspots, leading to an enhanced performance. The nanocomposite outperforms, exhibiting superior detection capabilities for R6G, MB, and MLN at concentrations of 10-6 M and CIP at concentration of 10-5 M, with impressive uniformity, reproducibility, stability, and analytical enhancement factors (EF) of 6.3 x 104, 2 x 104, 2.73 x 104 and 1.8 x 104 respectively. This approach provides a direct and cost-effective method for the detection of a broad spectrum of environmental pollutants and food additives, presenting potential applications across diverse domains. The detected environmental pollutants and food additives are removed through both catalytic degradation (R6G and MB) and adsorption (CIP and MLN).