Identification of heavy metal ions from aqueous environment through gold, Silver and Copper Nanoparticles: An excellent colorimetric approach

Biomaterials for reliable wearable health monitoring: Applications in skin and eye integration

Recent advancements in biomaterials have significantly impacted wearable health monitoring, creating opportunities for personalized and non-invasive health assessments. These developments address the growing demand for customized healthcare solutions. Durability is a critical factor for biomaterials in wearable applications, as they must withstand diverse wearing conditions effectively. Therefore, there is a heightened focus on developing biomaterials that maintain robust and stable functionalities, essential for advancing wearable sensing technologies. This review examines the biomaterials used in wearable sensors, specifically those interfaced with human skin and eyes, highlighting essential strategies for achieving long-lasting and stable performance. We specifically discuss three main categories of biomaterials-hydrogels, fibers, and hybrid materials-each offering distinct properties ideal for use in durable wearable health monitoring systems. Moreover, we delve into the latest advancements in biomaterial-based sensors, which hold the potential to facilitate early disease detection, preventative interventions, and tailored healthcare approaches. We also address ongoing challenges and suggest future directions for research on material-based wearable sensors to encourage continuous innovation in this dynamic field.

Highly sensitive electrochemical sensor for lead ions based on Bi-MOF/conducting polymer composites

Herein, conductive polyaniline (PANI) was chemically polymerized on the surface of a bismuth-based metal-organic framework (Bi-MOF) to form conductive PANI@Bi-MOF composites. FT-IR and PXRD measurements verified the successful production of PANI@Bi-MOF, whereas SEM, TEM, and EDAX mapping demonstrated that PANI was uniformly coated on the surface of Bi-MOF. The resulting PANI@Bi-MOF composites were characterized by cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS), then used to develop a sensitive electrochemical sensor for the detection of lead ions based on differential pulse anodic stripping voltammetry (DPASV). The developed sensor possessed a low detection limit of 0.0108 μg/L and a wide linear detection range (0.025-20 μg/L). The sensor was successfully applied for the detection of Pb2+ in real water samples, showing negligible response to other coexisting metal cations. This work offers a feasible approach for detecting Pb2+ ions in water.

Recent advances in designable nanomaterial-based electrochemical sensors for environmental heavy-metal detection

The detection of heavy metals serves as a defence measure to safeguard the well-being of the human body and the ecological environment. Electrochemical sensors (ECS) offer significant benefits such as exceptional sensitivity, excellent selectivity, affordability, and portability. This review begins by elucidating the ECS principles and delves into recent advancements in the field of heavy metal detection, including the use of metal nanoparticles, carbon-based nanomaterials, and organic framework materials. Advanced materials enhance the sensitivity and selectivity of ECS, allowing it to efficiently and rapidly identify metallic contaminants in food and the environment. Finally, the future development of ECS and challenges encountered in the development process are discussed, and testing materials for the detection of heavy-metal ions for human health and environmental safety are comprehensively considered. This study is likely to attract the interest of environmentalists and those who prioritise human health.

A data-driven framework to identify influencing factors for soil heavy metal contaminations using random forest and bivariate local Moran's I: A case study

The efficacy of traceability analysis is often limited by a lack of information on influencing factors for heavy metal (HM) contaminations in soil, such as spatial correlations between HM concentrations and influencing factors. To overcome this limitation, a novel data-driven framework was established to identify influencing factors for soil HM concentrations in an industrialised study area, in Guangdong Province, China, mainly using random forest (RF) and bivariate local Moran's I (BLMI) on the basis of the 577 soil samples and the 18 environmental covariates. The quantitative contributions of the 18 influencing factors for the Cd, As, Pb, and Cr concentrations were determined by the optimised RF. The main influencing factors of Cd were petrol stations (10.97%) and railways (9.99%), the main ones of As were groundwater depth (8.45%) and elevation (8.24%), the main ones of Pb were soil pH (8.82%) and hazardous waste disposal sites (8.02%), and the main ones of Cr were mine tailings (13.65%) and rainfall (11.88%). The eight spatial clustering maps between the four HM concentrations and the two key influencing factors were generated by BLMI. The middle part of the study area has shown the higher concentrations of Cd, As, Pb, and Cr, the more complex human activities and the more high-high clusters. Priority attention should be paid to the middle part when taking the specific prevention and control measures for their contaminations. This data-driven framework provided rich information on influencing factors, including HM concentrations, HM contaminations, quantitative contributions, and qualitative spatial clusters.

Euphorbia serpens extracts mediated synthesis of copper oxide nanoparticles and their biological applications

With the passage of time there is enormous development in the field of science and technology, however, human health remained the utmost concern. There are different strategies that helps us to treat various diseases but they have adverse reactions on our bodies. Nanobiotechnology is the advanced field consisting of new techniques and fabrication procedures for nanostructures for making drugs more effective against diseases in less time. These bio-nanoparticles easily target diseased cells, bind to them and damage the diseased tissue. Green synthesis of CuONPs is multi-purposed and can also be used for several bio-applications. The present study involves fabrication of economically viable copper oxide nanoparticles using aqueous plant extracts. The medicinal plants used in current study were Euphorbia serpens. The orchestrated nanoparticles were validated using several analytical techniques; Ultraviolet-Visible spectroscopy, XRD, SEM, FT-IR (Fourier-transform infrared), EDS, FT-IR and DLS (Dynamic light scattering). The average/mean size of the greenly fabricated nanoparticles was found to be 20.39 nm. Further, the biosynthesized NPs were evaluated for multiple biological activities. The bactericidal properties of green synthesized NPs were demonstrated using different bacterial strains revealing significant antibacterial potentials. The fungicidal properties were also demonstrated using different fungal strains showing significant antifungal potential. The minimum inhibitory concentration (MICs) values were calculated for different bacterial and fungal strains via disc-diffusion method. Further, our Euphorbia serpens orchestrated nanoparticles revealed excellent cytotoxic potentials against nascent brine shrimp larvae (IC50: 32.88 μg/mL) and have shown potential antioxidant properties. In conclusion, the asynthesized nanoparticles have shown significant in vitro bio-potentials. In future, different in vitro activities; antileishmanial, anticancer, enzyme degradation assays and different in vivo studies using animal models are recommended to further investigate the role of these NPs in different biomedical applications. Also, the formulations of multi-organic functional groups and biometallic NPs with regulated/balanced surface chemistry is worthy for the consideration.

Employing Mesoporous Nitrogen Containing Carbon for Simultaneous Electrochemical Detection of Heavy Metal Ions

Heavy metal ions are major contributors to water pollution, posing significant threats to both ecological balance and human health due to their carcinogenic properties. The increasing need for heavy metal detection highlights the advantages of electrochemical methods, which offer high sensitivity and efficiency. Herein mesoporous nitrogen containing carbon (MNC) was utilized for the simultaneous determination of heavy metals using square wave voltammetry technique in the established conditions of a buffer pH of 5.0. MNC demonstrated low detection limits (1, 10 and 50 μM), wide linear ranges (1 μM-6 mM, 10 μM-7 mM and 50 μM-17 mM), and high sensitivities (2.5 μA μM-1 cm-2, 1.03 μA μM-1 cm-2 and 5.14 mA mM-1 cm-2) for, Pb2+, Cd2+ and Cu2+, respectively. Moreover, the reproducibility, and selectivity of the sensor was investigated in the presence of K+, Mg2+, Zn2+, Ni2+, and Fe3+ which are the possible interferents present in water.

Associations Between Heavy Metal Exposure from Milk and Steroid Hormones in Mothers

Environmental exposure to heavy metals is ubiquitous. However, its relationship with steroid hormone levels is not well understood, particularly in pregnant women. This study investigated the association between prenatal heavy metal exposure and steroid hormone levels in an e-waste disposal area in China. We analyzed the Cd, Cr, Mn, Pb, Cu, and As concentrations in 102 human milk samples collected 4 weeks after delivery. Multiple regression analysis was used to assess the associations and interactions between heavy metals and steroidal hormones. We found positive associations between Mn and estrone and estriol (estrone: β = 0.713, 95%CI = 0.046, 1.381 and estriol: β = 1.290, 95%CI = 0.494, 2.085) and between Cd and progesterone (β = 0.280; 95%CI = 0.053, 0.506). We observed negative associations between Cr and estrone and estriol (estrone: β = - 0.757, 95%CI = - 1.473, - 0.041 and estriol: β = - 1.354, 95%CI = - 2.209, - 0.499). At last, we found that Pb was negatively associated with estrone (estrone: β = - 0.537, 95%CI = - 1.053, - 0.020). Our results suggest that exposure to heavy metals may affect steroid hormone levels in mothers living in an e-waste recycling area in China.

A simple turn-off fluorescent chemosensor based on a Schiff base structure for ultrafast and highly selective trace detection of Cu2+ ions in aqueous solutions

A simple turn-off fluorescent probe, 5-(diethylamino)-2-(hydrazonomethyl)phenol (DHP), is designed and synthesized for the sensitive and selective detection of Cu2+. The bright green fluorescence of DHP is quenched after the addition of Cu2+. The probe DHP exhibits good anti-interference performance against Cu2+ in the presence of multiple metal ions. The fluorescence intensity of DHP (10 μM) at 522 nm is well linearized with the Cu2+ concentration at 0-5 μM, and it has a detection limit of 0.29 nM (R2 = 0.9949). The complexation ratio of the probe DHP to Cu2+ is 2 : 1 and the complexation constant is 3.44 × 104 M-1 (R2 = 0.9974). In addition, the probe DHP can be recovered using EDTA and Cu2+ can be effectively monitored at pH 5-11, with good results in dipstick experiments and actual water samples. HepG-2 cells remained viable in excess of 90% after being exposed to DHP (50 μM) for 24 h, which demonstrates the extremely low toxicity of DHP, and it can be used for in vivo cell imaging.

A novel dual-detection electrochemiluminescence sensor for the selective detection of Hg2⁺ and Zn2⁺: Signal suppression and activation mechanisms

In this study, we developed a novel covalent organic framework (COF) material, termed RuCOFs, specifically designed and synthesized for electrochemiluminescence (ECL) sensor applications. RuCOFs are based on the classic ECL emitter Ru(dcbpy)32+, ingeniously integrating 4,4',4''-(1,3,5-triazine-2,4,6-triyl) triphenylamine (TAPT) with [2,2'-bipyridine]-5,5'-diamine (BPYDA), forming a structure with a high specific surface area. This configuration not only significantly enhances the stability of the ECL signal but also provides ideal N,N'-bipyridine chelating sites for efficient metal ion recognition. Utilizing Ru(dcbpy)32+-functionalized COF (RuCOFs), a novel dual-function ECL sensor was developed, achieving high sensitivity and selectivity in detecting mercury (Hg2⁺) and zinc (Zn2⁺) ions. Experimental results indicate that Hg2⁺ significantly quenches the ECL signal, while Zn2⁺ markedly enhances it, with detection limits of 4.71 nM for Hg2⁺ and 6.57 nM for Zn2⁺ across a wide linear response range from 1 μM to 1 nM. This research not only demonstrates the significant advantages of COF-based ECL sensing platforms in tracking environmental metal ions but also opens new possibilities for environmental monitoring.

A novel highly dispersed calcium silicate hydrate nanosheets for efficient high-concentration Cu2+ adsorption

Currently, the low cost and effective purification toward heavy metal ions in wastewater has garnered global attention. Herein, we used hydrothermal method to prepare highly dispersed calcium silicate hydrate in fluorite tailings. And the stacking thickness of calcium silicate hydrate layered morphology was less than 5 nm. For high concentration Cu2+ purification investigation in wastewater, we found that the equilibrium adsorption capacity reached 797.92 mg/g via the CSH with 3:2 Ca/Si molar ratio, be 1.43-21.8 times than that of reported data. Therein, the metal-metal exchange and deposition are the primary pathways for Cu2+ adsorption, and electrostatic attraction is the secondary pathway. And the relative ∼100 % removal rate of high-concentration Ni2+ and Cr3+ ions were confirmed via CSH prepared from different tailings. This method offers a cost-effective way to utilize tailings for preparing highly efficient adsorbents toward HMIs removal in wastewater.

Navigating the development of silver nanoparticles based food analysis through the power of artificial intelligence

In the ongoing pursuit of enhancing food safety and quality through advanced technologies, silver nanoparticles (AgNPs) stand out for their antimicrobial properties. Despite being overshadowed by other nanoparticles in food sensing applications, AgNPs possess inherent qualities that make them effective tools for rapid and selective contaminant detection in food matrices. This review aims to reinvigorate the interest in AgNPs in the food industry, emphasizing their sensing mechanism and the transformative potential of integrating them with artificial intelligence (AI) for enhanced food safety monitoring. It discusses key AI tools and principles in the food industry, demonstrating their positive impact on food analytical chemistry. The interplay between AI and biosensors offers many advantages and adaptability to dynamic analytical challenges, significantly improving food safety monitoring and potentially redefining the landscape of food safety and quality assurance.

Heavy metals toxicity on epigenetic modifications in the pathogenesis of Alzheimer's disease (AD)

Alzheimer's disease (AD) is a progressive decline in cognitive ability and behavior which eventually disrupts daily activities. AD has no cure and the progression rate varies unlikely. Among various causative factors, heavy metals are reported to be a significant hazard in AD pathogenesis. Metal-induced neurodegeneration has been focused globally with thorough research to unravel the mechanistic insights in AD. Recently, heavy metals suggested to play an important role in epigenetic alterations which might provide evidential results on AD pathology. Epigenetic modifications are known to play towards novel therapeutic approaches in treating AD. Though many studies focus on epigenetics and heavy metal implications in AD, there is a lack of research on heavy metal influence on epigenetic toxicity in neurological disorders. The current review aims to elucidate the plausible role of cadmium (Cd), iron (Fe), arsenic (As), copper (Cu), and lithium (Li) metals on epigenetic factors and the increase in amyloid beta and tau phosphorylation in AD. Also, the review discusses the common methods of heavy metal detection to implicate in AD pathogenesis. Hence, from this review, we can extend the need for future research on identifying the mechanistic behavior of heavy metals on epigenetic toxicity and to develop diagnostic and therapeutic markers in AD.

A NiO-nanostructure-based electrochemical sensor functionalized with supramolecular structures for the ultra-sensitive detection of the endocrine disruptor bisphenol S in an aquatic environment

Herein, NiO nanoparticles (NPs) functionalized with a para-hexanitrocalix[6]arene derivative (p-HNC6/NiO) were synthesized by using a facile method and applied as a selective electrochemical sensor for the determination of bisphenol S (BPS) in real samples. Moreover, the functional interactions, phase purities, surface morphologies and elemental compositions of the synthesized p-HNC6/NiO NPs were investigated via advanced analytical tools, such as Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Additionally, the synthesized p-HNC6/NiO NPs were cast on the surface of a bare glassy carbon electrode (GCE) via a drop casting method, which resulted in uniform deposition of p-HNC6/NiO/GCE over the surface of the GCE. Additionally, the developed p-HNC6/NiO/GCE sensor demonstrated an outstanding electrochemical response to BPS under optimized conditions, including a supporting electrolyte, a Briton-Robinson buffer electrolyte at pH 4, a scan rate of 110 mV s-1 and a potential window of between -0.2 and 1.0 V. The wide linear dynamic range was optimized to 0.8-70 μM to obtain a brilliant linear calibration curve for BPS. The limit of detection (LOD) and limit of quantification (LOQ) of the developed sensor were estimated to be 0.0059 and 0.019 μM, respectively, which are lower than those of reported sensors for BPS. The feasibility of the developed method was successfully assessed by analyzing the content of BPS in waste water samples, and good recoveries were achieved.

Nanodiamonds: A Cutting-Edge Approach to Enhancing Biomedical Therapies and Diagnostics in Biosensing

Nanodiamonds (NDs) have garnered attention in the field of nanomedicine due to their unique properties. This review offers a comprehensive overview of NDs synthesis methods, properties, and their uses in biomedical applications. Various synthesis techniques, such as detonation, high-pressure, high-temperature, and chemical vapor deposition, offer distinct advantages in tailoring NDs' size, shape, and surface properties. Surface modification methods further enhance NDs' biocompatibility and enable the attachment of bioactive molecules, expanding their applicability in biological systems. NDs serve as promising nanocarriers for drug delivery, showcasing biocompatibility and the ability to encapsulate therapeutic agents for targeted delivery. Additionally, NDs demonstrate potential in cancer treatment through hyperthermic therapy and vaccine enhancement for improved immune responses. Functionalization of NDs facilitates their utilization in biosensors for sensitive biomolecule detection, aiding in precise diagnostics and rapid detection of infectious diseases. This review underscores the multifaceted role of NDs in advancing biomedical applications. By synthesizing NDs through various methods and modifying their surfaces, researchers can tailor their properties for specific biomedical needs. The ability of NDs to serve as efficient drug delivery vehicles holds promise for targeted therapy, while their applications in hyperthermic therapy and vaccine enhancement offer innovative approaches to cancer treatment and immunization. Furthermore, the integration of NDs into biosensors enhances diagnostic capabilities, enabling rapid and sensitive detection of biomolecules and infectious diseases. Overall, the diverse functionalities of NDs underscore their potential as valuable tools in nanomedicine, paving the way for advancements in healthcare and biotechnology.

Pyrene-Based "Turn-On" Fluorescent Polymeric Probe with Thioacetal Units in the Main Chain for Mercury(II) Detection in Aqueous Solutions and Living Cells

A water-soluble polymeric pyrene-based polythioacetal (PTA-Py) with thioacetal units in the main chain is simply synthesized by direct polycondensation of 3, 6-dioxa-1, 8-octanedithiol, 1-pyrene formaldehyde, and mPEG2k-SH. The probe PTA-Py shows a good fluorescence response to Hg2+ ions due to the Hg2+-promoted deprotection reaction of thioacetal groups to regenerate the original 1-pyrene formaldehyde compound. After adding Hg2+ to the PTA-Py solution, the fluorescence intensity (FI) gradually increases with increasing concentrations of Hg2+. Compared with other metal ions, the probe exhibits high sensitivity, good selectivity, and rapid response to Hg2+. The low detection limits are 12.3 nm in ethanol-PBS buffer and 13.3 nm in water, respectively. The results imply that the simply synthesized water-soluble polymeric probe had potential applications in the rapid detection of Hg2+ ions in aqueous solutions. Moreover, the polymeric PTA-Py shows high sensitivity for CH3Hg+ with detection limits of 26.5 nm in ethanol/PBS buffer. In addition, PTA-Py can efficiently detect Hg2+ ions in HeLa cells. The results demonstrate that a valuable method is developed for biocompatible polymeric sensors for Hg2+ ions in biological and environmental samples.

From lab to ecosystem: Understanding the ecological footprints of engineered nanoparticles

Nanotechnology has attained significant attention from researchers in past decades due to its numerous advantages, such as biocompatibility, biodegradability, and improved stability over conventional drug delivery systems. The fabrication of engineered nanoparticles (ENPs), including carbon nanotubes (CNTs), fullerenes, metallic and metal oxide-based NPs, has been steadily increasing day due to their wide range of applications from household to industrial applications. Fabricated ENPs can release different materials into the environment during their fabrication process. The effect of such materials on the environment is the primary concern with due diligence on the safety and efficacy of prepared NPs. In addition, an understanding of chemistry, reactivity, fabrication process, and viable mechanism of NPs involved in the interaction with the environment is very important. To date, only a limited number of techniques are available to assess ENPs in the natural environment which makes it difficult to ascertain the impact of ENPs in natural settings. This review extensively examines the environmental effects of ENPs and briefly discusses useful tools for determining NP size, surface charge, surface area, and external appearance. In conclusion, the review highlights the potential risks associated with ENPs and suggests possible solutions.

Smartphone-integrated colorimetric and microfluidic paper-based analytical devices for the trace-level detection of permethrin

Permethrin is a pyrethroid pesticide and insect repellent that prevents mosquito-borne infections like dengue and malaria in tropical areas. This work describes a new colorimetric sensor based on metronidazole-stabilized silver nanoparticles (MTZ-AgNPs) for the first rapid, sensitive, and selective permethrin detection. The MTZ-AgNPs-based colorimetric sensor has a limit of detection (LOD) of 0.0104 µM and a limit of quantification (LOQ) of 0.0348 µM, respectively. The sensor is further integrated with smartphone and microfluidic fabrication of paper-based analytical devices (µPADs) for real-time and on-site detection of permethrin. Under optimal settings, no potential environmental contaminants interfere with permethrin detection, confirming its high selectivity. Finally, the practical applicability of sensors is confirmed in real tomato and apple extract samples. The US environmental protection agency's recommended UPLC method validated the detection efficiency of the proposed colorimetric sensor. The % recoveries from UPLC and MTZ-AgNPs suggest that the present sensor can quantitatively analyze permethrin in real samples.

Construction, characterization and application of locust bean gum/Phyllanthus reticulatus anthocyanin - based plasmonic silver nanocomposite for sensitive detection of ferrous ions

Iron is a transition metal of tremendous eco-physiological significance. This work aimed at constructing a simple plasmonic Ag-nanocomposite (LBG/PRAg-NC) based on locust bean gum and Phyllanthus reticulatus anthocyanin in a sustainable manner for the optical detection of ferrous ions (Fe²⁺) in aqueous solution. LBG/PRAg-NC was prepared via a green chemistry route and thoroughly characterized for its physico-chemical and plasmonic attributes. Successful synthesis of LBG/PRAg-NC under room temperature with Phyllanthus reticulatus anthocyanin as reductant and locust bean gum as stabilizer was accomplished within 15 min. LBG/PRAg-NC exhibited small size (∼8.04 nm), spherically shaped nanosilver, with good colloidal dispersion, stability and prominent SPR absorption peak at 420 nm. XPS analysis revealed the existence of both Ag⁰ and Ag ⁺ species embedded in the biopolymer support. Furthermore, LBG/PRAg-NC was highly selective for Fe²⁺ as opposed to other interferents including Fe³⁺. The presence of Fe²⁺ engendered a redox oxidation of the analyte by the Ag⁺ species, prompting a rapid, concentration dependent increase in color and SPR absorption band intensity of LBG/PRAg-NC colloidal solution. In aqueous solution, the probe displayed a good linear range for Fe²⁺ (0.1-100 μM), and a low detection limit (LOD of 0.38 μM). The obtained detection limit is much lower than the guideline limit of Fe²⁺ content in drinking water, ∼5 μM. Additionally, the probe was successfully applied in determination of Fe²⁺ in aqueous solutions of apple juice, iron supplement tablet, and tap water, with commendable analytical performances. Therefore, our research findings demonstrate a facile, efficacious, cost-effective, and eco-friendly approach for the sustainable synthesis of plasmonic Ag-nanocomposites based solely on locust bean gum and Phyllanthus reticulatus anthocyanin. Importantly, these results validate the capacity of plasmonic Ag-nanocomposite constructed via green chemistry route as a simple, rapid, and selective probe for effective monitoring of trace amounts of Fe²⁺ in aqueous environment.

Multiple fluorescence polymer dots-based differential array sensors for highly efficient heavy metal ions detection

Water pollution caused by harmful heavy metal ions (HMIs) can significantly impact aquatic ecosystems and pose a high risk to human health. In this work, equipped with ultra-high fluorescence brightness, efficient energy transfer, and environmentally friendly performance, polymer dots (Pdots) were employed to construct a pattern recognition fluorescent HMIs detection platform. A single-channel unary Pdots differential sensing array was first developed to identify multiple HMIs with 100% classification accuracy. Then an "all-in-one" multiple Förster resonance energy transfer (FRET) Pdots differential sensing platform was constructed to discriminate HMIs in the artificial polluted water samples and actual water samples, exhibiting high classification accuracy in distinguishing HMIs. The proposed strategy leverages the compounded cumulative differential variation of diverse sensing channels for analytes, which is anticipated to find extensive applications in other fields for detection purposes.

Colorimetric detection of chromium (VI) via its instigation of oxidase-mimic activity of CuO

Extensive use of chromium makes it one of the major pollutants of water resources. Chromium (VI) in particular is toxic and has detrimental health effects. Because of its high toxicity a tolerable concentration limit of chromium (VI) in drinking water has been recommended. Here we report a colorimetric method for determination of chromium (VI) in water based on the oxidase-like activity of solvothermal synthesized copper oxide. The particles have been characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). Using 3, 3', 5, 5'- tetramethylbenzidine (TMB) as a chromogenic substrate, CuO exhibited a pronounced oxidase-like activity in the presence of chromium (VI). This method enables successful colorimetric detection of chromium (VI). It demonstrated excellent selectivity for detection of chromium (VI) ions against potentially interfering ions. The method's feasibility to real sample analysis has been proven by testing tap water. Hence, we anticipate that the method can be successfully applied for analysis of chromium (VI) in environmental samples.

Rhodamine 6G derivative for the selective copper detection and remediation using nanoporous diatomaceous earth-engineered functional receptor

A rhodamine-derived receptor was synthesized and comprehensively characterized for structural confirmation. The receptor was able to distinguish the copper ions (Cu²⁺) from other competing cations. The yellow color of the receptor changed to pink upon adding Cu²⁺ ions, however, other competing cations ions were impotent towards any color variation. The UV-visible titration studies revealed the binding stoichiometry of a 1:1 ratio with a detection limit of 9.663 × 10^-8 M. Additionally, a novel idea of the work resides in the use of diatom for the practical application, where the receptor has been tethered on nanoporous diatomaceous earth microparticles (P2D) to remove Cu²⁺ ions. The results confirmed that 50 mg receptor functionalized DE could adsorb 10 mL of 1 ppm Cu²⁺ ions from water. Furthermore, a proof-of-concept device that is inexpensive, simple to operate, and continuously removes Cu²⁺ ions from water has been developed. The efficiency of the device in Cu²⁺ ion removal could be realized through the naked eye by observing the color change of P2D particles, which has excellent potential for application in remote locations where water contamination is a significant issue.

Combating Microbial Infections Using Metal-Based Nanoparticles as Potential Therapeutic Alternatives

The nature of microorganisms and the efficiency of antimicrobials have witnessed a huge co-dependent change in their dynamics over the last few decades. On the other side, metals and metallic compounds have gained popularity owing to their effectiveness against various microbial strains. A structured search of both research and review papers was conducted via different electronic databases, such as PubMed, Bentham, Springer, and Science Direct, among others, for the present review. Along with these, marketed products, patents, and Clinicaltrials.gov were also referred to for our review. Different microbes such as bacteria, fungi, etc., and their diverse species and strains have been reviewed and found to be sensitive to metal-carrying formulations. The products are observed to restrict growth, multiplication, and biofilm formation effectively and adequately. Silver has an apt use in this area of treatment and recovery, and other metals like copper, gold, iron, and gallium have also been observed to generate antimicrobial activity. The present review identified membrane disruption, oxidative stress, and interaction with proteins and enzymes to be the primary microbicidal processes. Elaborating the action, nanoparticles and nanosystems are shown to work in our favor in well excelled and rational ways.

Optimized porous carbon-fibre microelectrode for multiplexed, highly reproducible and repeatable detection of heavy metals in real water samples

This work demonstrates the simultaneous identification of four hazardous heavy metals in water samples, namely copper, lead, cadmium, and mercury. A simple yet selective electrode with the simplest fabrication procedure was used. The modified porous carbon threads coated with gold nanoparticles (AuNPs) was employed as a working electrode. The surface chemistry and morphology of the AuNPs deposited porous carbon thread surface were examined. The electrocatalytic activity of the metals on the Au-modified thread surface was observed using the differential pulse voltammetry (DPV) technique. Furthermore, all four metal ions were detected simultaneously, and no interference was observed. Individual and simultaneous experiments to test the impact of concentration revealed that the limit of detection (LoD) was observed to be 1.126 μM, 1.419 μM, 0.966 μM, 0.736 μM for the Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ metal ions respectively in a linear concentration range of 10-110 μM of each. Subsequently, the study of pH, interference with coexisting metal ions, repeatability study, and stability analysis was also performed. A real sample analysis utilising three different lake water samples is also carried out to further understand the application of the proposed sensor. A good recovery rate is achieved, and the results are reported. This work paves way for the on-field applicability of the present heavy metal detection platform.

Metal organic frameworks as promising sensing tools for electrochemical detection of persistent heavy metal ions from water matrices: A concise review

Water bodies are being polluted rapidly by disposal of toxic chemicals with their huge entrance into drinking water supply chain. Among these pollutants, heavy metal ions (HMIs) are the most challenging one due to their non-biodegradability, toxicity, and ability to biologically hoard in ecological systems, thus posing a foremost danger to human health. This can be addressed by robust, sensitive, selective, and reliable sensing of metal ions which can be achieved by Metal organic frameworks (MOF) based electrochemical sensors. In the present era, MOFs have caught greater interest in a variety of applications including sensing of hazardous pollutants such as heavy metal ions. So, in this review article, types, synthesis and working mechanism of MOF based sensors is explained to give general overview with updated literature. First time, detailed study is done for sensing of metal ions such as chromium, mercury, zinc, copper, manganese, palladium, lead, iron, cadmium and lanthanide by MOFs based electrochemical sensors. The use of MOFs as electrochemical sensors has attractive success story along with some challenges of the area. Considering these challenges, we attempted to highlight the milestone achieved and shortcomings along with future prospective of the MOFs for employing it in electrochemical sensing devices for HMIs. Finally, challenges and future prospects have been discussed to promote the development of MOFs-based sensors in future.

Detection of heavy metal ions using laser-induced breakdown spectroscopy combined with filter paper modified with PtAg bimetallic nanoparticles

The rapid and sensitive detection of heavy metal ions is important for environment and human health. Hence, the rapid and sensitive detection of multiple heavy metals simultaneously has become a critical issue. Here, we propose a method based on laser-induced breakdown spectroscopy (LIBS) combined with filter paper modified with PtAg bimetallic nanoparticles (BNPs) (LIBS-FP-PtAgBNPs) for the ultrasensitive detection of Hg²⁺, Cr³⁺, and Pb²⁺. The PtAgBNPs-modified filter paper was used to efficiently and specifically adsorb Hg, Cr, and Pb, and LIBS was used to detect the Hg, Cr, and Pb simultaneously. The limits of detection for Hg, Cr, and Pb were 0.5 μg/L (2.5 nM), 8 μg/L (0.15 μM), and 2 μg/L (9 nM), respectively. Furthermore, this method was successfully applied to determine the concentrations of Hg, Cr, and Pb in real spiked water samples. Compared with other methods based on nanoparticle sensing, LIBS-FP-PtAgBNPs is simpler to use and can achieve highly efficient enrichment, rapid separation, and sensitive detection of heavy metal ions. The optimal detections of Hg, Cr, and Pb were achieved in the pH range of 1-6. The developed method provides a new avenue to realize the rapid and sensitive detection of trace heavy metals in the environment.

Analytical chemistry toward on-site diagnostics

Analytical Chemistry, through quantitative and/or qualitative analysis (identification), is a discipline that involves the development of methodologies and the exploration of new principles to obtain answers to given problems. In situ analysis techniques have attracted attention for its ability to elucidate phenomena occurring and to evaluate amount of a certain component in substances at real time and biological samples as applications of such analysis technology. Lots of techniques have been performed to understand the fundamental phenomena in varied fields such as X-ray, vibrational, and electrochemical impedance spectroscopies and also analytical reagents that enable to semi-quantitative analysis just observation. In fact, applying various in situ techniques in analytical chemistry expands to the medical diagnosis, which leads to be able to detect early diseases. Here, we describe some of previous researches in many fields such as electrochemical device for energy storage, biology, environment, and pathology and briefly introduce our recent challenges to analytical chemistry toward the on-site diagnosis.

Gold Nanoparticles-Based Colorimetric Assays for Environmental Monitoring and Food Safety Evaluation

Recent years have witnessed an exponential increase in the research on gold nanoparticles (AuNPs)-based colorimetric sensors to revolutionize point-of-use sensing devices. Hence, this review is compiled focused on current progress in the design and performance parameters of AuNPs-based sensors. The review begins with the characteristics of AuNPs, followed by a brief explanation of synthesis and functionalization methods. Then, the mechanisms of AuNPs-based sensors are comprehensively explained in two broad categories based on the surface plasmon resonance (SPR) characteristics of AuNPs and their peroxidase-like catalytic properties (nanozyme). SPR-based colorimetric sensors further categorize into aggregation, anti-aggregation, etching, growth-mediated, and accumulation-based methods depending on their sensing mechanisms. On the other hand, peroxidase activity-based colorimetric sensors are divided into two methods based on the expression or inhibition of peroxidase-like activity. Next, the analytes in environmental and food samples are classified as inorganic, organic, and biological pollutants, and recent progress in detection of these analytes are reviewed in detail. Finally, conclusions are provided, and future directions are highlighted. Improving the sensitivity, reproducibility, multiplexing capabilities, and cost-effectiveness for colorimetric detection of various analytes in environment and food matrices will have significant impact on fast testing of hazardous substances, hence reducing the pollution load in environment as well as rendering food contamination to ensure food safety.

Particulate Matter and Its Components Induce Alteration on the T-Cell Response: A Population Biomarker Study

Compared with the T-cell potential of particulate matter (PM) in animal studies, comprehensive evaluation on the impairments of T-cell response and exposure-response from PM and its components in human population is limited. There were 768 participants in this study. We measured environmental PM and its polycyclic aromatic hydrocarbons (PAHs) and metals and urinary metabolite levels of PAHs and metals among population. T lymphocyte and its subpopulation (CD4⁺ T cells and CD8⁺ T cells) and the expressions of T-bet, GATA3, RORγt, and FoxP3 were measured. We explored the exposure-response of PM compositions by principal component analysis and mode of action by mediation analysis. There was a significant decreasing trend for T lymphocytes and the levels of T-bet and GATA3 with increased PM levels. Generally, there was a negative correlation between PM, urinary 1-hydroxypyrene, urinary metals, and the levels of T-bet and GATA3 expression. Additionally, CD4⁺ T lymphocytes were found to mediate the associations of PM_2.5 with T-bet expression. PM and its bound PAHs and metals could induce immune impairments by altering the T lymphocytes and genes of T-bet and GATA3.

Optical Sensing of Toxic Cyanide Anions Using Noble Metal Nanomaterials

Water toxicity, one of the major concerns for ecosystems and the health of humanity, is usually attributed to inorganic anions-induced contamination. Particularly, cyanide ions are considered one of the most harmful elements required to be monitored in water. The need for cyanide sensing and monitoring has tempted the development of sensing technologies without highly sophisticated instruments or highly skilled operations for the objective of in-situ monitoring. Recent decades have witnessed the growth of noble metal nanomaterials-based sensors for detecting cyanide ions quantitatively as nanoscience and nanotechnologies advance to allow nanoscale-inherent physicochemical properties to be exploited for sensing performance. Particularly, noble metal nanostructure e-based optical sensors have permitted cyanide ions of nanomolar levels, or even lower, to be detectable. This capability lends itself to analytical application in the quantitative detection of harmful elements in environmental water samples. This review covers the noble metal nanomaterials-based sensors for cyanide ions detection developed in a variety of approaches, such as those based on colorimetry, fluorescence, Rayleigh scattering (RS), and surface-enhanced Raman scattering (SERS). Additionally, major challenges associated with these nano-platforms are also addressed, while future perspectives are given with directions towards resolving these issues.

Recent Progress in Nanotechnology-Based Approaches for Food Monitoring

Throughout the food supply chain, including production, storage, and distribution, food can be contaminated by harmful chemicals and microorganisms, resulting in a severe threat to human health. In recent years, the rapid advancement and development of nanotechnology proposed revolutionary solutions to solve several problems in scientific and industrial areas, including food monitoring. Nanotechnology can be incorporated into chemical and biological sensors to improve analytical performance, such as response time, sensitivity, selectivity, reliability, and accuracy. Based on the characteristics of the contaminants and the detection methods, nanotechnology can be applied in different ways in order to improve conventional techniques. Nanomaterials such as nanoparticles, nanorods, nanosheets, nanocomposites, nanotubes, and nanowires provide various functions for the immobilization and labeling of contaminants in electrochemical and optical detection. This review summarizes the recent advances in nanotechnology for detecting chemical and biological contaminations in the food supply chain.

A novel 2-dimensional nanocomposite as a mediator for the determination of doxorubicin in biological samples

In our study, the electrochemical properties of a novel activated nanocomposite were studied with 2-dimensional graphitic carbon nitride/sodium dodecyl sulfate/graphene nanoplatelets on the screen-printed electrodes (2D-g-C₃N₄/SDS/GNPs/SPE). The as-fabricated sensor exhibited excellent electrochemical performance, including wide dynamic ranges from 0.03 to 1.0 and 1.0-13.5 μM with a low limit of detection (LOD) of 10.0 nM. The fabricated 2D-g-C₃N₄/SDS/GNPs/SPE electrode exhibited high sensitivity, stability, good reproducibility, reusability, and repeatability towards DOX sensing. It can be utilized in real samples, including human plasma and urine, with excellent correlations and coefficients of variation below 6.0%. Therefore, this study presents potential application values in sensing DOX with efficient performance. Finally, the accuracy was attested by comparison with high-performance liquid chromatography (HPLC) as the reference method, signalizing a good agreement.

Fabrication of sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide nanocomposite for electrochemical monitoring of 4-aminophenol

4-aminophenol (4-AP) is one of the major environmental pollutants which is broadly exploited as drug intermediate in the pharmaceutical formulations. The extensive release of 4-AP in the environment without treatment has become a serious issue that has led several health effects on humans. This work describe the determination of 4-AP through a new chemically modified sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide (PVA/WO₃/rGO) nanocomposite. The fabricated nanocomposite was characterized through XRD and HR-TEM to confirm the crystalline structure with average size of 35.9 nm and 2D texture with ultra-fine sheets. The electrochemical characterization of fabricated sensor was carried out by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to ensure the charge transfer kinetics of modified sensor that revealed high conductivity of PVA/WO₃/rGO/GCE. Under optimized conditions e.g. scan rate 80 mV/s, phosphate buffer (pH 6) as supporting electrolyte and potential window from -0.2 to 0.8 V, the prepared sensor showed excellent response for 4-AP. The linear dynamic range of developed method was optimized as 0.003-70 μM. The LOD of fabricated sensor based on PVA/WO₃/rGO/GCE for 4-AP was calculated as 0.51 nM. The practical application of PVA/WO₃/rGO/GCE was tested in real water and pharmaceutical samples. The fabricated sensor presented here, exhibited exceptional stability and sensitivity than the reported sensors and could be effectively used for the monitoring 4-AP without interferences.

Recent Advances in Adsorptive Nanocomposite Membranes for Heavy Metals Ion Removal from Contaminated Water: A Comprehensive Review

Water contamination is one of the most urgent concerns confronting the world today. Heavy metal poisoning of aquatic systems has piqued the interest of various researchers due to the high toxicity and carcinogenic consequences it has on living organisms. Due to their exceptional attributes such as strong reactivity, huge surface area, and outstanding mechanical properties, nanomaterials are being produced and employed in water treatment. In this review, recent advances in the use of nanomaterials in nanoadsorptive membrane systems for wastewater treatment and heavy metal removal are extensively discussed. These materials include carbon-based nanostructures, metal nanoparticles, metal oxide nanoparticles, nanocomposites, and layered double hydroxide-based compounds. Furthermore, the relevant properties of the nanostructures and the implications on their performance for water treatment and contamination removal are highlighted. The hydrophilicity, pore size, skin thickness, porosity, and surface roughness of these nanostructures can help the water permeability of the nanoadsorptive membrane. Other properties such as surface charge modification and mechanical strength can improve the metal adsorption effectiveness of nanoadsorptive membranes during wastewater treatment. Various nanocomposite membrane fabrication techniques are also reviewed. This study is important because it gives important information on the roles of nanomaterials and nanostructures in heavy metal removal and wastewater treatment.

Natural and Engineered Nanomaterials for the Identification of Heavy Metal Ions—A Review

In recent years, there has been much interest in developing advanced and innovative approaches for sensing applications in various fields, including agriculture and environmental remediation. The development of novel sensors for detecting heavy metals using nanomaterials has emerged as a rapidly developing research area due to its high availability and sustainability. This review emphasized the naturally derived and engineered nanomaterials that have the potential to be applied as sensing reagents to interact with metal ions or as reducing and stabilizing agents to synthesize metallic nanoparticles for the detection of heavy metal ions. This review also focused on the recent advancement of nanotechnology-based detection methods using naturally derived and engineered materials, with a summary of their sensitivity and selectivity towards heavy metals. This review paper covers the pros and cons of sensing applications with recent research published from 2015 to 2022.

Facile synthesis of Cu NPs@Fe3O4-lignosulfonate: Study of catalytic and antibacterial/antioxidant activities

Environmental pollution is one of the important concerns for human health. There are different types of pollutants and techniques to eliminate them from the environment. We hereby report an efficient method for the remediation of environmental contaminants through the catalytic reduction of the selected pollutants. A green method has been developed for the immobilization of copper nanoparticles on magnetic lignosulfonate (Cu NPs@Fe₃O₄-LS) using the aqueous extract of Filago arvensis L. as a non-toxic reducing and stabilizing agent. The characterization of the prepared Cu NPs@Fe₃O₄-LS was achieved by vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD), scanning TEM (STEM), thermogravimetry-differential thermal analysis (TG/DTA), fast Fourier transform (FFT), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron (XPS) analyses. The synthesized Cu NPs@Fe₃O₄-LS was applied as a magnetic and green catalyst in the reduction of Congo Red (CR), 4-nitrophenol (4-NP), and methylene blue (MB). The progress of the reduction reactions was monitored by UV-Vis spectroscopy. Finally, the biological properties of the Cu NPs@Fe₃O₄-LS were investigated. The prepared catalyst demonstrated excellent catalytic efficiency in the reduction of CR, 4-NP, and MB in the presence of sodium borohydride (NaBH₄) as the reducing agent. The appropriate magnetism of Cu NPs@Fe₃O₄-LS made its recovery very simple. The advantages of this process include a simple reaction set-up, high and catalytic antibacterial/antioxidant activities, short reaction time, environmentally friendliness, high stability, and easy separation of the catalyst. In addition, the prepared Cu NPs@Fe₃O₄-LS could be reused for four cycles with no significant decline in performance.

An improved electrochemical sensor based on triton X-100 functionalized SnO2 nanoparticles for ultrasensitive determination of cadmium

The drastic increases in the concentration of heavy metals ions in the environment have become a serious concern for a number of years. Heavy metals pose serious impacts on human and aquatic life and cause severe health hazards. Amongst heavy metals, cadmium is known for its lethal effects on human health as it easily reacts with enzymes and creates free radicals in the biological system that causes carcinogenicity and other serious diseases. Thus, to tackle this challenge, TX-100 SnO₂ nanoparticles based chemically modified sensor is introduced to assess the quantity of Cd⁺² in the water system. The engineered SnO₂ nanoparticles were electrochemically characterized through cyclic voltammetry and electrochemical impedance spectroscopy to ensure the better charge transfer kinetics and electrocatalytic properties of fabricated sensors. Under the optimized conditions e.g., scan rate 80 mV/s, PBS electrolyte pH 7, and potential window (-0.2 to -1.4 V), the engineered TX-100/SnO₂/GCE-based sensor manifested a phenomenal response for cadmium ions in water media. The LOD and LOQ of developed TX-100/SnO₂/GCE were calculated in the nanomolar range as 0.0084 nM and 0.27 nM. The recovery values of the proposed method for Cd⁺² were found in an acceptable limit that witnesses the effectiveness of the fabricated sensor. Moreover, the excellent stability and anti-interference behavior of the sensor highlights its dynamic profile to be commercially utilized for the determination of Cd⁺² ions in water bodies.

Poly(carbazole-co-1,4-dimethoxybenzene): Synthesis, Electrochemiluminescence Performance, and Application in Detection of Fe3+

In this study, four polycarbazole derivatives (PCMB-Ds) with different alkyl side chains were designed and synthesized via Wittig–Horner reaction. A novel solid-phase electrochemiluminescence (ECL) system was prepared by immobilizing PCMB-D on an indium tin oxide (ITO) electrode with polyvinylidene fluoride (PVDF) in the presence of tripropylamine (TPrA). It could be found that the increase in alkyl side chain length had little effect on the ECL signal of PCMB-D, while the increase in the degree of polymerization (DP) greatly enhanced the ECL signal. Furthermore, the P-3/ITO ECL sensor based on the polyoctylcarbazole derivative (P-3) with the best ECL performance was successfully constructed and detected Fe³⁺ under the optimal experimental conditions. The ECL signal steadily diminished with the increased concentration of Fe³⁺ because of the competition and complexation between Fe³⁺ and P-3 under the condition of pH 7.4. This P-3/ITO platform could realize a highly sensitive and selective detection of Fe³⁺ with a wide detection range (from 6 × 10⁻⁸ mol/L to 1 × 10⁻⁵ mol/L) and low detection limit of 2 × 10⁻⁸ mol/L, which could allow the detection of Fe³⁺ in multiple scenarios, and would have a great application prospect.

High durability of food due to the flow cytometry proved antibacterial and antifouling properties of TiO2 decorated nanocomposite films

Although polymeric membrane has superior properties, its applications in biomedical and food industrial fields are minimal. Biofouling is a significant concern in the membrane, created from particular interactions between the membrane and untreated water content. This research showed that a careful superhydrophilic modification of polyethersulfone membrane could address those drawbacks that have hindered their utility. Hence, a combination of chemical and physical modification showed far-reaching effects on surface behavior, affecting manifold aspects of its bacterial attachment, protein adsorption resistance, and hydrophilicity. The contact angle measurement results decreased from 30° to 0° in 26 s, and surface free energy increased by 33%, demonstrating the shifting surface wettability behavior toward the Superhydrophilicity. Besides, increasing the average surface roughness on the nanoscale and forming 70-110 nm jagged structures results in a marked reduction in protein adsorption, bacterial adhesion, and biofouling formation, confirmed by the results of Flow cytometry analysis and microtiter plate assay. An improved understanding of antifouling and antibacterial properties will greatly assist in food industries since it can be applied to enhance the durability of food and chemical materials. This is important as it gives us a simple way of improving packing reliability, reducing costs and amounts of undesirable waste products.

Fabrication of activated carbon supported modified with bimetallic-platin ruthenium nano sorbent for removal of azo dye from aqueous media using enhanced ultrasonic wave

Herein, activated carbon supported modified with bimetallic-platin ruthenium nano sorbent (PtRu@AC) was synthesized by a thermal decomposition process and used in the removal of methylene blue (MB) from aqueous solutions. The synthesized nano sorbents were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS) spectroscopic techniques. The data obtained from characterization studies showed that PtRu@AC nano sorbent was highly crystalline and in a form of PtRu alloy with a monodispersed composition. The results indicated that the maximum adsorption capacity (qemax) for the removal of MB with PtRu@AC under optimum conditions was detected to be 1.788 mmol/g (569.4 mg/g). The experimental kinetic results of the study revealed that the adsorption of methylene blue was found to be more compatible with the false second-order model compared to some tested models. Calculations for thermodynamic functions including enthalpy change (ΔHo), entropy change (ΔSo), and Gibbs free energy change (ΔGo) values were performed to get an idea about the adsorption mechanism. As a result, the synthesized PtRu@AC nano adsorbent was detected as a highly effective adsorbent material in the removal of MB from aquatic mediums.

Preconcentrations of Cu (II) and Mn (II) by magnetic solid-phase extraction on Bacillus cereus loaded γ-Fe2O3 nanomaterials

For the simultaneous preconcentrations of Cu(II) and Mn(II), a novel preconcentration technique was developed and described. Bacillus cereus loaded magnetic ɣ-Fe₂O₃ nanoparticles were prepared and used as support materials on solid-phase extraction procedure. Important experimental parameters were investigated in details and pH 6.0, 3 mL min^-1 of flow rate, 5 mL of 1 mol L^-1 of HCl as eluent, 200 mg of biomass, and 200 mg of magnetic ɣ-Fe₂O₃ nanoparticles as support material was found as the best conditions. The preconcentrations factor were found to be 80 for Cu (II) and Mn(II). It was confirmed by the results that SPE columns could be used in 32 cycles. The LOD values calculated for Cu (II) and Mn (II) were 0.09 and 0.08 ng mL^-1, respectively. The RSD values found were less than 3.4%. The extraction recoveries were achieved as higher than 98%. The biosorption capacities of Cu (II), and Mn (II) were 26.0 mg g^-1, 30.3 mg g^-1 respectively. The approach devised for analyzing analyte concentrations in food samples proved to be successful.

Pomegranate Punica granatum peel waste as a naked-eye natural colorimetric sensor for the detection and determination of Fe+3 and I- ions in water

The utilization of renewable and abundant agricultural waste such as Pomegranate (Punica granatum L.) peel extract has been developed wherein a simple extraction of dried peel in water offered a natural sensor; ensuing yellowish solution comprising phenolic compounds reacted explicitly to detect Fe⁺³ and I^- solutions by naked-eye. The UV-Vis absorption spectrum of the resulting extracted mixture was drastically changed toward the longer wavelengths only after the addition of the Fe³⁺ and I^- while there was no discernible spectral change due to the addition of a broad range of other common cations and anions. In the case of Fe³⁺ and I^-, the transformation can be followed by the naked eye in the concentration range of 5 × 10^-4 M and 1 × 10^-2 M, respectively. An acceptable and reasonable detection with 47.05426 μM efficiency was attained in comparison to other Fe³⁺ indicators such as ferroin.