μM Hg2 Research Articles

Nitrogen and Sulfur Co-doped Carbon Dots for Ratiometric Fluorometric Determination of Mercury Ions.

Nitrogen and sulfur co-doped carbon dots (N, S-CDs) were prepared for dual-channel ratiometric fluorescence determination of mercury ions (Hg2+). The dual-emission N, S-CDs were synthesized using a simple one-pot hydrothermal treatment. When excited with visible light, N,S-CDs exhibited two emission peaks at 390 and 500nm. Notably, the presence of Hg2+ caused a considerable decrease in the fluorescence of N, S-CDs at 500nm, mainly due to the static quenching effect. In comparison, the fluorescence at 390nm was almost unchanged. With a limit of detection (LOD) of 0.21 µM for Hg2+, the N, S-CDs were successfully applied to the unlabeled ratiometric fluorescence determination of Hg2+ in actual water samples with good recoveries (94.5-107.8%). In conclusion, this developed ratiometric fluorescent sensor provides a reliable, environmentally friendly, rapid, and efficient platform for detecting Hg2+ in environmental applications.

Rhodamine-benzothiazole-thiophene: A triangular molecular tool for simultaneous detection of Hg2+ and Cu2+

A novel rhodamine-benzothiazole fluorescent chemosensor, bridged with a thiophene unit, is designed for the turn-on detection of Hg2+ and Cu2+. Noteworthy findings include impressively low limits of detection (0.007 μM for Hg2+ and 0.013 μM for Cu2+), a determined sensing mechanism involving spirolactam ring opening and hydrolytic cleavage, consistent 1:1 binding stoichiometry for both metal ions and an optimal pH of around 6. The sensor’s practical applicability is demonstrated through successful implementation in HeLa cells and zebrafish, along with effective analyte recovery in various water samples. This work advances the field by providing a highly sensitive and versatile chemosensor for environmental and biological applications.

Bio‐Fabricated Silver Nanoparticles for Catalytic Degradation of Toxic Dyes and Colorimetric Sensing of Hg2+

AbstractIn the present study, silver nanoparticles were synthesized via green synthesis using fenugreek (Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min−1), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min−1) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min−1). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg2+, making them excellent solid bio‐based sensors for mercury sensing.

Doxorubicin as a Drug Repurposing for Disruption of α-Chymotrypsinogen-A Aggregates.

Protein conformation is affected by interaction of several small molecules resulting either stabilization or disruption depending on the nature of the molecules. In our earlier communication, Hg2+ was known to disrupt the native structure of α-Cgn A leading to aggregation (Ansari, N.K., Rais, A. & Naeem, A. Methotrexate for Drug Repurposing as an Anti-Aggregatory Agent to Mercuric Treated α-Chymotrypsinogen-A. Protein J (2024). https://doi.org/10.1007/s10930-024-10187-z ). Accumulation of β-rich aggregates in the living system is found to be linked with copious number of disorders. Here, we have investigated the effect of varying concentration of doxorubicin (DOX) i.e. 0-100 µM on the preformed aggregates of α-Cgn A upon incubation with 120 µM Hg2+. The decrease in the intrinsic fluorescence and enzyme activity with respect to increase in the Hg2+ concentration substantiate the formation of aggregates. The DOX showed the dose dependent decrease in the ThT fluorescence, turbidity and RLS measurements endorsing the dissolution of aggregates which were consistent with red shift in ANS, confirming the breakdown of aggregates. The α-Cgn A has 30% α-helical content which decreases to 3% in presence of Hg2+. DOX increased the α-helicity to 28% confirming its anti-aggregatory potential. The SEM validates the formation of aggregates with Hg2+ and their dissolution upon incubation with the DOX. Hemolysis assay checked the cytotoxicity of α-Cgn A aggregates. Docking revealed that the DOX interacted Lys203, Cys201, Cys136, Ser159, Leu10, Trp207, Val137 and Thr134 of α-Cgn A through hydrophobic interactions and Gly133, Thr135 and Lys202 forms hydrogen bonds.

A hybrid fluorescent probe for the selective detection of divalent Hg2+ and trivalent Al3+ ions and their biological applications

Metals are extensively used for different applications in agriculture and industry. Accumulations of these metals in the environment lead to serious health concerns. Currently, fast and accurate detection of metal ions in the environment or biological system has become a critical issue. Hence, developing an appropriate tool for the detection of metals can help reduce environmental metal pollution and reduce health concerns. In the present study, a hybrid fluorescent probe or chemosensor for parallelly detecting two important metal ions (Mercury and Aluminium) has been designed and tested for its detection efficiency. The newly synthesized chemosensor 3′,6′-bis(ethylamino)-2′,7′-dimethyl-3H-spiro[isobenzofuran-1,9′-xanthen]-3-one (RS) was found to specifically detect Hg2+ and Al3+ ions with high sensitivity and selectivity. The chemical and physical properties of chemosensor RS were tested using single-crystal X-ray diffraction, UV and Fluorescence analysis. The quick response to Hg2+ and Al3+ is attributable to the creation of a coordinate bond present between the chemosensor RS and the metal ion. The selective sensing of chemosensor RS is due to the spirolactam ring opening followed by the development of proper coordinate geometry in the chemosensor. 1H NMR titration experiment and Job’s approach studies suggest a significant binding stoichiometry between the chemosensor RS and the metal ions at a 1:1 ratio. The limit of detection (LOD) of chemosensor RS was determined to be 1.88 µM for Al3+ and 1.75 µM for Hg2+ ions. The in vivo studies using two experimental animal models, Drosophila melanogaster (fruit fly) and Poecilia reticulate (guppy fish), clearly demonstrate its efficiency in detecting endogenously absorbed Hg2+ and Al3+. Thus, chemosensor RS can selectively and simultaneously detect Hg2+ and Al3+ in biological or environmental samples and can help us in monitoring metal leaching into the environment.

Harnessing photocurrent enhancement in silver-bacterial cellulose nanocomposite for ultra-sensitive Hg2+ electrochemical detection

Global health and ecosystem concerns over mercury pollution require stringent monitoring. Herein, we showcase a novel approach for detecting trace Hg2+ ions in water using cyclic voltammetry (CV). Our approach involves modifying glassy carbon electrode (GCE) and screen printed electrode (SPE) surfaces with a nanocomposite of ascorbic acid-capped silver nanoparticles (AsAgNPs) embedded in nanocrystalline bacterial cellulose (AsAgNP-NBC). Analytical techniques confirmed the nanocomposite’s stability and morphological characteristics, exhibiting high accuracy within a linear range of 10 nM to 1 µM Hg2+ and a low limit of detection (LOD) of 3.531 nM. Additionally, on irradiation with 455 nm light source, AsAgNP-NBC modified SPE displayed a remarkable 9.6 times enhanced photocurrent, achieving an LOD of 3.95 pM, and enhanced photoresponsivity of 55.2 mA W−1, showcasing its potential for ultra-trace level detection. This cost-effective and biocompatible nanocomposite presents a promising alternative to conventional analytical methods for selective detection of trace Hg2+ ions in environmental samples.

A Fluorescent Probe for Hg2+ Specific Recognition Based on Xanthene and its Application in Food Detection and Cell Imaging.

The mercury-loving unit aminothiourea was introduced into the xanthene fluorophore to synthesized the probe molecule NXH. NXH has a specific response to Hg2+, and with the addition of (0 ~ 50 µM) Hg2+, the fluorescence intensity of the probe solution was quenched from 2352 a.u. to about 308 a.u. NXH exhibited excellent detection performance of high sensitivity (LOD = 96.3 nM), real-time response (105s), wide pH range (2.1 ~ 9.3), and strong anti-interference ability for Hg2+. At the same time, NXH has wide range of applications for Hg2+ detection, which can fluorescence imaging of Hg2+ in Hela cells and tea samples, and can also be made into Hg2+ detection test paper.

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

BackgroundRemoval of heavy metals from water and soil is a pressing challenge in environmental engineering, and biosorption by microorganisms is considered as one of the most cost-effective methods. In this study, the metal-binding proteins MerR and ChrB derived from Cupriavidus metallidurans were separately expressed in Escherichia coli BL21 to construct adsorption strains. To improve the adsorption performance, surface display and codon optimization were carried out.ResultsIn this study, we constructed 24 adsorption engineering strains for Hg2+ and Cr6+, utilizing different strategies. Among these engineering strains, the M’-002 and B-008 had the strongest heavy metal ion absorption ability. The M’-002 used the flexible linker and INPN to display the merRopt at the surface of the E. coli BL21, whose maximal adsorption capacity reached 658.40 μmol/g cell dry weight under concentrations of 300 μM Hg2+. And the B-008 overexpressed the chrB in the intracellular, its maximal capacity was 46.84 μmol/g cell dry weight under concentrations 500 μM Cr6+. While in the case of mixed ions solution (including Pb2+, Cd2+, Cr6+ and Hg2+), the total amount of ions adsorbed by M’-002 and B-008 showed an increase of up to 1.14- and 4.09-folds, compared to the capacities in the single ion solution.ConclusionThe construction and optimization of heavy metal adsorption strains were carried out in this work. A comparison of the adsorption behavior between single bacteria and mixed bacteria systems was investigated in both a single ion and a mixed ion environment. The Hg2+ absorption capacity is reached the highest reported to date with the engineered strain M’-002, which displayed the merRopt at the surface of chassis cell, indicating the strain’s potential for its application in practical environments.

Simultaneous electrochemical and colorimetric detection of tri-heavy metal ions in environmental water samples employing 3D-MOF/nickel selenide as a synergistic catalyst

The detrimental growth of water pollutants such as heavy metal ions (HMI) has become a life-threatening problem in the modern era. Therefore, developing more efficient strategies to detect such compounds requires increased attention. In this study, we designed a dual-mode assay for electrochemical sensing and naked-eye (colorimetric) detection of HMI using the peroxidase mimic activity of the developed nanozyme. The nanozyme of choice, which possesses both the necessary electrochemical properties and the ability to be oxidized with 3,3′,5,5′-tetramethylbenzidine (TMB), was determined and studied. Flower-like nickel selenide (NiSe) was integrated with a zeolitic imidazole framework (ZIF-67) to enable its wider applicability. HMI detection with a wide linear range of about 0.029–764.8 µM (Cd2+), 0.299–355.5 µM (Pb2+), and 0.29–153.2 µM (Hg2+) with NiSe/ZIF showed excellent electrochemical performances, while the linear range in colorimetric detection was about 0.199–429.9 µM (Cd2+), 0.199–90.8 µM (Pb2+), and 0.149–276.8 µM (Hg2+). The limit of detection for the simultaneous detection was 5.2 nM (Cd2+), 4.7 nM (Pb2+), and 6.2 nM (Hg2+) for electrochemical sensing. The LOD obtained for the colorimetric analyses were 0.043 µM (Cd2+), 0.050 µM (Pb2+), and 0.091 µM (Hg2+). The real sample analysis of the environmental water samples showed good results for trace heavy metal ions. Thus, the developed NiSe/ZIF catalyst is more effective with dual detection and can be used for portable analysis of several targets with further modifications.

An amphiphilic dansyl based multianalyte sensor for the detection of Hg2+, PPi, and TNP: A three-in-one chemical sensor

A fluorescent dansyl-based amphiphilic probe, 5-(dimethylamino)-N-hexadecylnaphthalene-1-sulfonamide (DLC), was synthesized and characterized to detect multiple analytes at different sensing environments. In acetonitrile, DLC detects nitro explosives such as trinitrophenol (TNP) and 2,4-dinitrophenol (2,4-DNP) by an emission “on-off” response method, and the detection limits (LOD) were estimated to be as low as 4.3 µM and 17.4 µM, respectively. Amphiphilic long chains of the probe were embedded into lipid bilayers to form nanoscale vesicles DLC.Ves. Nanovesicular probe DLC.Ves was found to be highly selective for Hg2+ among other metal ions and for pyrophosphate (PPi) ions among various anions. DLC.Ves could detect Hg2+ with a turn “on–off” emission and PPi with ratiometric change in emission at 525 nm. It is proposed that DLC.Ves could detect Hg2+ via the Hg2+-induced aggregation quenching mechanism and PPi through the Hydrogen bonding. The LODs are estimated as 6.41 µM and 70.9 µM for Hg2+ and PPi, respectively. 1H NMR, SEM, and fluorescence lifetime measurements confirmed the binding mechanism. Thus, it is believed that the simple fluorescent probe DLC could be a prominent sensor to detect multiple analytes depending on the sensing medium.

Synthesis of Os@ZIF-8 nanocomposites with enhanced peroxidase-like activity for detection of Hg2.

Metal organic framework (MOF)-derived nanostructures display remarkable characteristics and have broad application potential. Os@ZIF-8 nanocomposites were prepared by a depositional method. The Os nanoparticles distributed on the surface of ZIF-8. The nanocomposites displayed enhanced peroxidase-like activity with smaller Km for both 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 compared to Os NPs due to the confinement effect and large surface area that ZIF-8 provided. From the average reaction rate constants obtained from three different temperatures, the activation energy values were determined. The kinetic data indicated that the Os@ZIF-8 NCs are catalytically more active than Os NPs. In addition, quantitative measurement of Hg2+ was performed based on the formation of Os-Hg alloy. Os@ZIF-8 NCs had a wide detection range between 0 μM and 71.43 μM for Hg2+ with a limit of detection (LOD) of 2.29 μM. Using a MOF with a large surface area to load Os nanoparticles to achieve enhanced nanozyme activity is the novelty of this work.

Synthesis of Upper-Rim Sulfanylpropyl- and p-Methoxyphenylazo-Substituted Calix[4]arenes as Chromogenic Sensors for Hg2+ and Ag+ Ions.

A series of calix[4]arenes with upper-rim sulfanylpropyl and p-methoxyphenylazo groups (compounds 8-10) were synthesized and found to be effective chromogenic sensors for selectively detecting Hg2+, Hg+, and Ag+ ions among 18 screened metal perchlorates. In comparison to previously reported diallyl- and dithioacetoxypropyl-substituted calix[4]arenes (5, 6, 14, 15, and 16) and the newly synthesized compound 7, the distal (5,17)-disulfanylpropyl-substituted di-p-methoxyphenylazocalix[4]arene 9 demonstrated superior performance with a limit of detection of 0.028 μM for Hg2+ ions in a chloroform/methanol (v/v = 399/1) cosolvent. Job's plot revealed 1:1 binding stoichiometry for all these upper-rim sulfanylpropyl- and p-methoxyphenylazo-substituted calix[4]arenes 8-10 with Hg2+ ions, and Benesi-Hildebrand plots from ultraviolet/visible (UV-vis) titration spectra were used for the determination of their association constants. Our findings indicated that the distal orientation of two p-methoxyphenylazo and two sulfanylpropyl groups in calix[4]arenes 8-10 is more favorable for binding Hg2+ ions than the proximal (5,11-) orientation; moreover, the adjacent sulfanylpropyl groups exhibited superior coordination as ligands compared to the allyl and thioacetoxypropyl groups. Notably, compounds 8-10 displayed a comparable trend in their association with Ag+ ions, albeit with 1 order of magnitude lower binding constants and a distinct binding mode compared to Hg2+ ions. UV-vis spectroscopy, Job's plots, high-resolution mass spectrometry, and 1H nuclear magnetic resonance titration studies are presented and discussed.

Quick transformation of polymeric waste into high valuable N-self doped carbon quantum dot for detection of heavy metals from wastewater

Preparing carbon dots (CDs) from waste materials is essential in the current scenario. Herein, we converted non-disposable environmental pollutants into multifaceted, robust, and cost-effective sensing nitrogen-doped fluorescent CDs (N-CQDs) to quickly detect analytes in a wide range of samples. Herein, we studied the simple and efficient way for large-scale synthesis of the N-CQDs from waste melamine sponge (WMS) and lemon juice (LJ) by the treatment of concentrated sulphuric acid (H2SO4) within 10 min and the yield of 60.9 wt% obtained, much higher than those from traditional processes. As-prepared N-CQDs showed bright blue fluorescence and were significantly quenched with Hg2+ (turn off) completely regained by S2− (turn on) due to higher affinity S2− towards Hg2+. The detection limit was 1.04 µM for Hg2+ and 1.62 µM for S2−. This study provides a new perspective for developing N-CQDs and selective sensing Hg2+ and S2− from wastewater.

Enhanced photoreduction of mercury (II) ions over MnCo2O4-modified wrinkled BaSnO3 nanosheets prepared by solvothermal method under visible light

Photocatalytic reduction of heavy metal ions utilizing nanostructured semiconductor photocatalysts is a promising ecological way, thanks to its simplicity and feasibility. In this article, the improved photoreduction of mercury (II) ions (Hg2+) is achieved over wrinkled barium stannate (BaSnO3) nanosheets modified by manganese cobaltate (MnCo2O4) nanoparticles. The MnCo2O4 was coupled to solvothermally-produced BaSnO3 at 4.0–16.0 wt% by impregnation. The MnCo2O4/BaSnO3 heterojunctions showed mesoporous surfaces with 133–150 m2 g1 of surface areas. The visible light harvesting is improved owing to bandgap reduction down to 2.31 eV for 9.0 wt% MnCo2O4-impregnated BaSnO3 compared to 2.99 eV for the bare BaSnO3. The complete photoreduction of 368.30 µM Hg2+ utilizing 9.0% MnCo2O4/BaSnO3 is achieved at a dosage of 2.4 gLẌ with a rate of 69.54 µM min–1 in 30 min. This optimized photocatalyst is also recyclable five times with 97% of its initial performance. The magnificent activity of MnCo2O4/BaSnO3 is accredited to the improved visible-light harvesting and efficient charge separation by the controllable impregnation of MnCo2O4.

A colorimetric chemosensor for Cu2+/Hg2+ based on a cycloruthenated 2-phenylbenzimidazole

A cyclometalated ruthenium complex (1) with 2-phenylbenzimidazole as the ligand was synthesized and used as a colorimetric chemosensor to detect Hg2+ and Cu2+. It is interesting that the presence of Hg2+ caused a blue-shifted absorption of 1 from 560 to 450 nm resulting in a solution color change from red to yellow, while the addition of Cu2+ resulted in an attenuated absorption along with the solution color changing from red to colorless. Their corresponding detection limits were calculated to be 0.25 µM for Hg2+ and 0.45 µM for Cu2+, respectively. Moreover, the slips of paper were dyed with complex 1 and then successfully used to recognize Hg2+ and Cu2+ by naked eyes, respectively. Furthermore, 1 was also used to determine Hg2+ and Cu2+ in some spiked water samples, respectively.

Investigation of the Siderophore Production and Associated Heavy Metal Accumulation Potential of Brevibacillus laterosporus 301/İK3-2

Siderophores are secondary metabolites released into the environment by various microorganisms, fungi, and plants to chelate iron from the surrounding environment. It is known that siderophores bind to other metals besides iron. Today, heavy metals, which are released as an undesirable result of industrial development, accumulate at high rates and pose a significant threat to biological living things. In this sense, remediation of heavy metal-contaminated sites is an urgent requirement. Siderophores are promising agents for the removal of heavy metals from natural habitats with the role of bioremediation. 
 In this study, the effect of heavy metals on the growth and siderophore production of Brevibacillus laterosporus was investigated. Maximum siderophore production was determined as 50 % at 48 h in the metal-free growth media. In addition, maximum siderophore production was determined for various heavy metals including 5 μM Hg2+, 0.5 mM Ni2+, 0.1 mM Co2+, and 2.5 μM Fe2+. Intracellular uptake of the mercury was also measured using optical emission spectroscopy and compared with siderophore production values of the B. laterosporus. The maximum biosorption of mercury was measured to be 40% in 5 μM Hg2+-containing media at 48 h of incubation. The results show that siderophore production is affected by uptake of various metals, and are usable for removing of heavy metals from environmental habitats.

A highly hydrophilic hydrazone-linked covalent organic framework as a fluorescent multianalyte sensor for detection of Cu2+ and Hg2+ in aqueous solution

Heavy metal pollution is of great threat to public health and the environment, and an effective method to detect and remove toxic heavy ions from water is highly desirable. The emerging covalent organic frameworks (COFs) with well-defined pore structures and specific functional units provide an excellent platform for fluorescent sensing. The hydrazone-linked framework material SH-COF with excellent hydrophilicity and abundant chelating sites was synthesized by bottom-up strategy under solvothermal conditions. The resultant SH-COF with specific binding sites was proposed to detect and remove Cu2+ and Hg2+. The SH-COF also exhibited the characteristics of high selectivity, high sensitivity, a lower limit of detection (0.244 μM for Cu2+ and 0.239 μM for Hg2+), and real-time response. Furthermore, the highly selective interaction of Cu2+ or Hg2+ with SH-COF was confirmed by X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectra. A proposed sensing mechanism of COF for Cu2+ and Hg2+ was presented. This research also demonstrates the great potential of COFs in practical sensing applications.

Synthesis of multicolor silver nanostructures for colorimetric sensing of metal ions (Cr3+, Hg2+ and K+) in industrial water and urine samples with different spectral characteristics

In this work, we have synthesized four different color (yellow, orange, green, and blue (multicolor)) silver nanostructures (AgNSs) by chemical reduction method where silver nitrate, sodium borohydride and hydrogen peroxide were used as reagents. The as-synthesized multicolor AgNSs were successfully functionalized with bovine serum albumin (BSA) and applied as a colorimetric sensor for the assaying of metal cations (Cr3+, Hg2+, and K+). The addition of metal ions (Cr3+, Hg2+, and K+) into BSA functionalized AgNSs (BSA-AgNSs) causes the aggregation of BSA-AgNSs, and are accompanied by visual color changes with red or blue shift in the surface plasmon resonance (SPR) band of BSA-AgNSs. The BSA-AgNSs show different SPR characteristic for each metal ions (Cr3+, Hg2+, and K+) with exhibiting different spectral shift and color change. The yellow color BSA-AgNSs (Y-BSA-AgNSs) act as a probe for sensing Cr3+, orange color BSA-AgNSs (O-BSA-AgNSs) act as probe for Hg2+ ion assay, green color BSA-AgNSs (G-BSA-AgNSs) act as a probe for the assaying of both K+ and Hg2+, and blue color BSA-AgNSs (B-BSA-AgNSs) act as a sensor for colorimetric detection of K+ ion. The detection limits were found to be 0.26 μM for Cr3+ (Y-BSA-AgNSs), 0.14 μM for Hg2+ (O-BSA-AgNSs), 0.05 μM for K+ (G-BSA-AgNSs), 0.17 μM for Hg2+ (G-BSA-AgNSs), and 0.08 μM for K+ (B-BSA-AgNSs), respectively. Furthermore, multicolor BSA-AgNSs were also applied for assaying of Cr3+, and Hg2+ in industrial water samples and K+ in urine sample.

Self-assembly and phase transition of gold nanoclusters in natural deep eutectic solvent for visual detection of toxicants in water environment

Ecological damage derived from water pollution has increased greatly accompanying by the development of industries, which promotes the exploration of water environment monitoring platform. Structure-oriented synthesis of gold nanoclusters (NADES-Au NCs) based on novel natural deep eutectic solvent (NADES), has been successfully obtained without the use of any stabilizer or capping agents. With the pH stability and photobleaching resistance in the complex environment, spongy NADES-Au NCs showed superior optical properties than other forms. Moreover, this green sensing platform based on NADES-Au NCs displayed two well-separated emission peaks at 440 and 669 nm, respectively. There was a linear range of 0.5–200 µM with a detection limit of 0.25 µM for Hg2+ and a linear range of 1–150 µM with a detection limit of 0.12 µM for nitroanilines. Such NADES-Au NCs demonstrated the satisfactory recoveries and reliabilities in water samples, which presented great potential of water pollution detection. Simultaneously, the application of NADES as a green solvent for the synthesis of metal nanoclusters may provide new avenues for sensing platform.

Xanthan Gum-Mediated Silver Nanoparticles for Ultrasensitive Electrochemical Detection of Hg2+ Ions from Water

An environmentally safe, efficient, and economical microwave-assisted technique was selected for the production of silver nanoparticles (AgNPs). To prepare uniformly disseminated AgNPs, xanthan gum (XG) was utilized as both a reducing and capping agent. UV–Vis spectroscopy was used to characterize the formed XG-AgNPs, with the absorption band regulated at 414 nm under optimized parameters. Atomic force microscopy was used to reveal the size and shape of XG-AgNPs. The interactions between the XG capping agent and AgNPs observed using Fourier transform infrared spectroscopy. The XG-AgNPs were placed in between glassy carbon electrode and Nafion® surfaces and then deployed as sensors for voltammetric evaluation of mercury ions (Hg2+) using square-wave voltammetry as an analytical mode. Required Nafion® quantities, electrode behavior, electrolyte characteristics, pH, initial potentials, accumulation potentials, and accumulation durations were all comprehensively investigated. In addition, an electrochemical mechanism for the oxidation of Hg2+ was postulated. With an exceptional limit of detection of 0.18 ppb and an R2 value of 0.981, the sensors’ measured linear response range was 0.0007–0.002 µM Hg2+. Hg2+ evaluations were ultimately unaffected by the presence of many coexisting metal ions (Cd2+, Pb2+, Cr2O4, Co2+,Cu2+, CuSO4). Spiked water samples were tested using the described approach, with Hg2+ recoveries ranging from 97% to 100%.