Chemosensing of metal ions is a matter of great interest for researchers. Imidazole is an electron-rich molecule that tends to coordinate specifically with metal ions and has an electron-donor nitrogen atom. Therefore, multiple metals, including Cu 2+ , Mg 2+ , Hg 2+ , Al 3+ , and Zn 2+ , have been reported to employ imidazole-based chemosensors. This review comprehensively covers metal-ion detection and relevant governing mechanisms in imidazole-driven chemosensors. Electron transfer is the most prominent mechanism, while energy transfer, ligand-to-metal charge transfer (LMCT), and metal-to-ligand charge transfer (MLCT) are the least reported mechanisms describing the interaction between metal ions and imidazoles. These sensors exhibit a trend of lower detection limit for metal ions using fluorescence spectroscopy compared to UV/Vis spectroscopy. Critical analysis highlights some underrepresented metal ions and shows that there is still room for improvement. Furthermore, unraveling the mechanism of interaction between the imidazoles and ions will fascinate researchers to develop economical, sensitive, selective, and robust sensors for deciphering the intricate world of metals.

Groundwater, a vital source essential for life, is under threat due to human activities, facing both contamination and rapid depletion. The current study underscores the importance of understanding the complex interplay between human activities, lithological variations, and their impact on groundwater quality. The research focuses on Shahdra Town in northern Lahore, Pakistan, for modelling and simulation to assess anticipated groundwater levels and quality. A total of 08 tube wells were selected for study. The borehole data of selected tube wells were used to visualize 2D and 3D fence models (Rockworks, Ver 16 ®) for the variation in lithology. Based on the similarity in the lithology, the tube wells are divided into four groups. The groundwater samples from all locations were analyzed for 20 parameters and compared against the Punjab Environmental Quality standards. The results showed a high total dissolved solids concentration (1080 mg/L), alkalinity (270 mg/ L), and the concentrations of metals (Pb, As, and Co) were very high as per WHO guidelines. The concentration of parameters was used to draw Piper diagrams, Stiff diagrams, and Scholler diagrams, which illustrated the dominance of anion facies (carbonate and bicarbonate) and cation facies (Na and K). The metal concentrations were plotted on a GIS map (ArcGIS Ver 10.4 ®), which showed that the locations near the river Ravi have high metal concentrations due to the discharging of groundwater. To study the depletion rate of groundwater, a calibrated simulation model (MODFLOW 2011.1 ®) was used. It was found that if the current conditions prevailed, then the groundwater drawdown would be 0.52 m/decade. The additional installation of a tubewell will enhance the drawdown up to 0.82 m/decade. The government should strictly implement the water policy, which is approved but yet to be enforced.

These days, optical sensors are getting considerable interest of researchers due to their portability and rapid on-site detection abilities for metal ions. In this paper, a Schiff base 2-((4-(dimethylamino)benzylidene)amino)acetic acid (DMAB-G) was studied for its optical sensing properties towards metals ions i.e. Al3+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+, Hg2+, Pb2+, AsO2− and La3+. This naked eye probe showed a selective color change from colorless to pale yellow only for mercuric (Hg2+) ions which is consistent with red shift from 342 nm to 448 nm having an LOD of 1.71 × 10− 6 M in aqueous medium which make it better sensor compared to literature reported ones. Furthermore, calculations revealed a DMAB-G bound with Hg2+ ions in a ratio of 2:1 with an association constant of 1.7 × 103 M− 2. FT-IR data suggested that DMAB-G interacted with mercuric ions by coordination through nitrogen of imine group and carbonyl of carboxyl moieties which was further confirmed by DFT-Calculations.

In this work, a nanocomposite material based on kaolin - mixed metal oxides (derived from H21[B3W39O132].69 h2O) was successfully synthesized by simple co-precipitation and wet impregnation method and characterized by various spectrochemical methods. Then their adsorption potential was explored using anionic Congo red (CR) dye under variable factors of time, dose, temperature, agitation rate and pH. The composite K-Al-{BW11}@Kao exhibited the hybrid characteristic of kaolin and mixed metal oxides. Successful distribution of mixed metal oxides K-Al-{BW11} on kaolin was confirmed by morphological analysis. This distribution enhanced the adsorption capacity of the kaolin for anionic dye removal. K-Al-{BW11}@Kao removed 91.02 +/- 1.22% dye in 35 min, using 0.05 g composite. The adsorption kinetics of CR best fitted pseudo 2nd order model, which indicated that the rate limiting step was chemisorption. The qmax values of CR adsorption on kaolin and K-Al-{BW11}@Kao were 11.3 +/- 0.03 and 17 +/- 0.02 mg/g respectively. A higher value of Langmuir R2 coefficient and thermodynamics studies indicated that the chemisorption of CR by KAO was spontaneous and exothermic in nature. This work offers a facile method for producing bifunctional material for the adsorption of Congo red dye.

Naked eye optical chemosensors have gained considerable attraction by researchers due to their low cost, selectivity, sensitivity and rapid on the spot detection properties. In this work, a Schiff base “4-(4-(dimethylamino)benzylidene)amino-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one” (DMAB-AAP) was studied for its visual sensing properties to detect heavy metals ions however, it shows discriminating color changes from colorless to lemon yellow and greenish yellow for ferrous (Fe2+) and lanthanum (La3+) ions, which is consistent to red shift from 362 nm to 421 nm and 438 nm having limit of detection 8.201× 10^-7 M and 4.911× 10^-7 M, respectively, in the UV–Vis. absorption spectrum of DMAB-AAP. Moreover, stoichiometric binding of DMAB-AAP with Fe2+ and La3+ was found to be in 1:1 ratio. The LOD of DMAB-AAP for ferrous ions is significantly lower than WHO tolerable limits (5µM) in drinking water. Importantly, as no other Schiff base has been reported for colorimetric sensing of lanthanum, therefore, the LOD of DMAB-AAP for lanthanum ions is found comparable with various electrochemical methods.

Catecholamines and their metabolites play critical physiological roles in the human body. Paragangliomas and pheochromocytomas are rare adrenal tumors that significantly alter catecholamine metabolism, particularly the concentrations of metanephrine (MN) and normetanephrine (NMN). This study presents the development and validation of a rapid and straightforward analytical method using reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a photodiode array (PDA) detector for quantifying MN and NMN in 24-hour urine samples. Sample preparation involved adding 1mL of urine to a tube containing the internal standard 3-methoxy-4-hydroxy benzylamine hydrochloride (MHBA) and a 2g/L solution of 2-aminoethyl-diphenylborinate. After vortex mixing and centrifugation, ethyl acetate was used for extraction, and the organic layer was dried under nitrogen at 50–60°C before reconstitution in the mobile phase. Chromatographic separation was achieved on an RP C-18 column with an isocratic flow of the mobile phase (sodium dihydrogen phosphate, citric acid monohydrate, acetonitrile, and sodium octyl sulfate). Detection was performed at 347nm, with peak identification based on standard retention times. The method was validated for linearity (10–2000 ng/mL), recovery, sensitivity, precision, accuracy, selectivity, carryover, stability, and dilution effects. It showed a strong correlation coefficient (>0.99) and accuracy within ±15%. Inter- and intra-day precision confirmed the method reliability. This validated technique is suitable for clinical and research applications involving catecholamine metabolite screening.

The interface area created by contact/coupling of two or more semiconductors, named heterojunction has proved worthy for promoting the movement of photogenerated charges on photocatalysts. Hence, increases the photocatalytic performance. Copper oxide /tungsten oxide heterojunction nanocomposites with different molar concentrations (0.05 M, 0.1 M) of copper oxide were synthesized through a simple co-precipitation method, and tungsten oxide (WO3) nanoparticles were also prepared for comparative analysis. Techniques such as UV-visible, FTIR, XRD, PL, and SEM were employed to characterize synthesized materials. The photocatalytic activity of synthesized nanomaterials was also investigated concerning the photodegradation of Methylene blue (MB) dye solution (10 ppm) under sunlight. Maximum (92 %) degradation of dye was achieved by calcined (0.1 M) CuOWO3 photocatalyst compared to WO3 photocatalyst which showed a degradation capacity of 40 % at the same exposure time of 180 min. Copper oxide enhanced the photocatalytic activity of nanocomposites.

Water contamination is a serious global issue, and exploring efficient water purification methods is of significant importance to research community to achieve sustainable development goals (SDGs). Widely explored low-cost and environmentally beneficial technique is biosorption, which uses inexpensive materials to adsorb contaminants from the wastewater. Ionic liquids (ILs), a significant class of liquid organic salts with melting temperatures below 100 °C, are composed of both organic and inorganic ion pairs bonded by weak electrostatic interactions. Recently, ILs have been employed to purify water both through extraction as well as adsorption techniques. This study explores, for the very first time, the effects of differently natured (acidic, basic, and neutral) ILs on the biosorption potentials of activated carbon of brewed tea that is a domestic food waste. Acidic IL-functionalized activated carbon (MAC-A) was found to be particularly effective in removing Orange G (OG) dye from the aqueous solutions. ILs are observed to enhance the structural properties of biosorbent by improving its morphology and reducing the crystallinity that in turn, helps in improved active sites. Biosorbent was performing best under mild conditions; room temperature, neutral pH, and fast sorption equilibrium (90 min). The practical adsorption capacity of MAC-A for OG was 30 mg/g, which is greater than many of the biomass-based biosorbents reported in the literature. The IL-functionalized MAC-A exhibited good recyclability up to the 3 runs. These facts mark the IL-functionalized MAC-A an appealing cost-effective choice for OG-contaminated wastewater treatment.

Sulfur doped carbon dots (SCDs) are being evolved as one of the rising stars due to their marvelous properties i.e. distinctive physical and chemical features, stability, ease of synthesis, cost-effectiveness and green nature, which make them suitable for their wide applications in various fields, including sensing, bio-medical, photocatalysis, corrosion inhibition, food safety, etc. The introduction of sulfur containing groups in addition to natural surface moieties such as –C = O, –COOH, –OH, –OR etc. enables them as a potential candidate for above-mentioned applications. This review targets the role of SCDs in various applications and the chemistry behind these applications. Furthermore, SCDs have also been critically evaluated for their limitations for future improvements.

Sulfonamides and their derivatives are being used as potent chemosensors for various ions. Sensing ability of 4-methyl-N-(pyridin-2-yl) benzene-1-sulfonamide (S) was tested towards different cations i.e. Zn2+, Fe2+, Pb2+, Ni2+, Sr2+, Cd2+, Cu2+, Co2+, Hg2+ and Al3+ in Dimethyl Sulfoxide (DMSO). S exhibited sensitivity towards ferrous (Fe2+) and cupric (Cu2+) ions. Solution of S turned yellow from colorless upon interaction with iron and copper ions and a corresponding bathochromic shift was observed. Electronic spectra showed new absorbance peaks at 310 nm and 370 nm after interaction with Fe2+ and Cu2+ respectively, compared with S absorbance peak at 270 nm. Binding studies indicated 1:1 binding stoichiometry of both metal ions with S. Detection limits for iron and copper were determined to be 0.74 µM and 0.60 µM, respectively. However, their binding constant values came out to be 1.3 × 106 M−1 and 1 × 106 M−1 respectively for Fe2+ and Cu2+.

Pyrazole-derived Schiff bases are mostly designed for the optical sensing of ionic species. In this research, a pyrazole-based Schiff base, 4-(4-methoxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (MBz-AAP), has been studied for its optical sensing properties towards various ionic species, including heavy metal ions and anions. Among these species, this probe exhibits a color change from colorless to maroonish-red for Fe2+ and Cu2+ ions, and colorless to yellow for HSO_4^ - ions. These optical changes are found to be consistent with red shifts in the ultraviolet-visible absorption spectrum of MBz-AAP from 334 to 504, 510, and 387 nm for Fe2+, Cu2+, and HSO4– ions, respectively. Limits of detection (LOD) of MBz-AAP for Fe2+, Cu2+, and HSO_4^ - ions are calculated to be 2.45, 3.34, and 2.24 μM, respectively. These LODs for Fe2+ and Cu2+ are much lower than their allowable limits in drinking water, i.e., 5.36 and 31.5 μM, respectively. Moreover, the stoichiometric binding ratios of Fe2+, Cu2+, and HSO_4^ - with MBz-AAP are determined to be 1 : 1, with binding constants of 5.0 × 103, 1.6 × 103, and 7.05 × 103 M–1, respectively.

Hard tissue regenerative mesoporous bioactive glass (MBG) has traditionally been synthesized using costly and toxic alkoxysilane agents and harsh conditions. In this study, MBG was synthesized using the cheaper reagent SiO2 by using a co-precipitation approach. The surface properties of MBG ceramic were tailored by functionalizing with amino and carboxylic groups, aiming to develop an efficient drug delivery system for treating bone infections occurring during or after reconstruction surgeries. The amino groups were introduced through a salinization reaction, while the carboxylate groups were added via a chain elongation reaction. The MBG, MBG-NH2, and MBG-NH-COOH were analyzed by using various techniques: x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy and energy-dispersive x-ray spectroscopy. The XRD results confirmed the successful preparation of MBG, and the FTIR results indicated successful functionalization. BET analysis revealed that the prepared samples were mesoporous, and functionalization tuned their surface area and surface properties. Cefixime, an antibiotic, was loaded onto MBG, MBG-NH2, and MBG-NH-COOH to test their drug-carrying capacity. Comparatively, MBG-NH-COOH showed good drug loading and sustained release behavior. The release of the drug followed the Fickian diffusion mechanism. All prepared samples displayed favorable biocompatibility at higher concentration in the Alamar blue assay with MC3T3 cells and exhibited the good potential for hard tissue regeneration, as carbonated hydroxyapatite formed on their surfaces in simulated body fluid.

Water pollution is a pressing global concern due to the uncontrolled discharge of organic pollutants into aquatic environments without adequate treatment. One significant contributor is the release of organic dyes, notably Congo red (CR) dye, from industrial effluents, posing environmental and health risks. In response, a highly effective 2D porous material, the PEG-ZnO/rGO composite, has been developed for the removal of CR dye from water systems. The composite was thoroughly characterized using XRD, FTIR, SEM, AFM and EDX analytical techniques to assess its crystalline nature, functionalities, surface morphology, 3D structure and elemental composition. Under optimized conditions (pH 3, 3 mg adsorbent dose and 0.5 mM CR dye concentration), the PEG-ZnO/rGO composite demonstrated a remarkable 94

Glucocorticoids are widely used as highly effective drugs for treating inflammatory diseases. In this study, a method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously determine four glucocorticoids, including betamethasone, dexamethasone, hydrocortisone, and prednisolone in unauthorized or unregulated medicinal powders often associated with quackery formulations. Commercially available standards were used for method development and glucocorticoid detection. Glucocorticoids were extracted from the samples with methanol, which were then chromatographically separated using two mobile phases (0.1 % formic acid in water and 0.1 % formic acid in acetonitrile) in an isocratic flow on an Agilent Poroshel 120 C18 column (2.1 mm x 75 mm x 2.7 m). The validated analytical measuring range (AMR) of betamethasone and dexamethasone was 7.8–500 ng/mL, whereas, for hydrocortisone and prednisolone, AMR was 7.8–1000 ng/mL. The method showed an excellent coefficient of determination (r2) >0.990 for betamethasone, hydrocortisone, and prednisolone, while for dexamethasone 0.986. Accuracy and precision (intra/inter days) of these glucocorticoids showed a bias of 6–15 % (<20 %) and a coefficient of variation (CV) of <15 %. For each dilution factor, the integrity of samples was maintained after dilution. The developed method is sensitive and valuable for detecting, quantifying, and confirming the selected glucocorticoids in various quackery formulation powders commonly used in Pakistani setups.

Recently, nickel nanoparticles (NiNPs) have become the center of attention due to their promising features including excellent surface area to volume ratio, eco-friendly or nontoxic nature and excellent reactivity. NiNPs possess catalytic, photocatalytic, anti-bacterial, anti-fungal, electrochemical and anti-oxidant properties in different industrial and medical applications. This review summarizes the physiochemical/biological procedures and characterization techniques alongwith their main role and limitations which were used for the formation of NiNPs. This study also discussed techniques applied for the preparation of NiNPs, preparation methodology, reaction parameters that affect properties of NiNPs and phytochemical analysis of different plants presented in the literature has been critically reviewed. Hypothetical procedures for the reduction/stabilization of Ni ions by quercetin or santin, antibacterial/antimicrobial potential and catalysis of 4-nitrophenol are also discussed.

Sulfonamides are auspicious chemosensors which are capable to bind with ionic species through various ways like complexation, charge transfer, proton transfer etc. and produce a detection signal in the form of an optical change either in visible or UV-light and for electronic as well as fluorimetric spectra. Sulfonamides have gained much attention of analytical chemists these days as these are inexpensive, robust, green in nature and some what sensitive and selective to many anionic and cationic species. Due to their promising versatility in sensing properties, these are under great consideration in forensic, environmental, analytical and biochemistry laboratories. This review narrates how sulfonamides are being used to optically sense ionic species.

The contamination of freshwater bodies via inappropriately released wastewater can be effectively prevented using membrane separation methods at the point of industrial discharge. Graphene oxide (GO), an allotrope of carbon, has adjustable physicochemical characteristics and a lot of potential for environmental cleanup. Due to its narrow and variable interlayer spacing the flux and dyes removal ability of GO membrane is low. To resolve this problem, current study reports the fabrication of tetramethyl thiourea (TMTU)-doped reduced GO (TMTU@rGO) using microwave method. TMTU@rGO is nanoporous material with increased surface area and pore volume as compared to GO. The prepared TMTU@rGO was utilized for the fabrication of nanofiltration membrane to remove cationic and anionic industrial dyes such as Methylene blue (MB), Rhodamine B (RB) and Congo Red (CR). The TMTU@rGO composite-based nanofiltration membrane was characterized using various characterization techniques, i.e., FTIR, EDX, XRD, SEM, BET, AFM, contact angle and zeta potential. The TMTU@rGO composite-based nanofiltration membrane showed 99

With the widespread use of pesticides, environmental pollution has elevated to a top priority for humans. The pentachlorophenol (PCP) is one of the most dangerous chlorophenols, employed as pesticides, fungicides, and wood preservatives. In the current study, a nickel-aluminum layered double hydroxide modified glassy carbon electrode (Ni-Al-LDH@GCE) was used to build a straight forward, environmentally friendly, and accurate electrochemical sensor for the measurement of PCP. The fabricated Ni-Al-LDH was principally assessed using a variety of characterization methods to confirm its functionalities, morphology, porosity and crytallanity. The proposed Ni-Al-LDH@GCE sensor was also characterized electrochemically for the evaluation of its conductivity using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The linear dynamic range of the developed ultra-sensitive Ni-Al-LDH@GCE based electrochemical method was found as 0.05 to 50 µM at a scan rate of 50 mV/s in Britton-Robinson buffer of pH 6 for PCP. The limit of detection (LOD) and limit of quanitification (LOQ) of electrochemical sensor for PCP were determined as 0.004 μM and 0.0132 μM, respectively. The sensor's analytical suitability was evaluated using real water samples that showed the acceptable recovery values.