Ion Sensor Research Articles

A novel fluorescent sensor for diammonium and metal ions based on a supramolecular charge-transfer complex of bis(aza-18-crown-6)-containing dienone.

A bis(aza-18-crown-6)-containing 2,5-di(benzylidene)cyclopentanone and a bis(ammoniopropyl) derivative of 1,2-di(4-pyridyl)ethylene in MeCN were found to form a supramolecular charge-transfer complex, which can act as an "off-on" fluorescent sensor for the Ca2+ and 1,12-dodecanediammonium ions. The molecular structure of this complex in solution was studied by density functional theory calculations.

Normal-Direction Graded Hemispheres for Ionic Flexible Sensors with a Record-High Linearity in a Wide Working Range.

Flexible pressure sensors developed rapidly with increased sensitivity, a fast response time, high stability, and excellent deformability. These progresses have expanded the application of wearable electronics under high-pressure backgrounds while also bringing new challenges. In particular, the nonlinearity and narrow working range lead to a gradually insensitive response, principally because the microstructure deforms inconsistently on the device interfaces in the whole working range. Herein, we report an ionic flexible sensor with a record-high linearity (R2 = 0.99994) in a wide working range (up to 600 kPa). The linearity response comes from the normal-direction graded hemisphere (GH) microstructure. It is prepared from poly(dimethylsiloxane) (PDMS)/carbon nanotubes (CNTs)/Au into flexible and deformable electrodes, and its geometry is precisely designed from the linear elastic theory and optimized through finite element simulation. The sensor can achieve a high sensitivity of S = 165.5 kPa-1, a response-relaxation time of <30 ms, and superb consistency, allowing the device to detect vibration signals. Our sensor has been assembled with circuits and capsulation in order to monitor the function state of players in underwater sports in the frequency domain. This work deepens the theory of linearized design of microstructures and provides a strategy to make flexible pressure sensors that have combined the performances of ultrahigh linearity, high sensitivity, and a wide working range.

Flexible solid-state Zn-Co MOFs@MXene supercapacitors and organic ion hydrogel sensors for self-powered smart sensing applications

Stable and continuous detection of physiological signals without an external power supply is a crucial technology to realize wearable electronics as the next generation of flexible electronic devices. In this work, a self-powered smart system with flexible solid-state Zn-Co MOFs@MXene supercapacitors and polyacrylamide-BaTiO3/NaCl (PAM-BTO/NaCl) organic ionic hydrogel sensors are designed. The supercapacitor demonstrates a high energy density of 51 Wh/kg at a power density of 1.59 kW/kg. In particular, it maintains exceptional mechanical flexibility under different bending environments. The resistance change rate of the organic ionic hydrogel sensor exhibits a linear response within the strain range of 0–400 % and 400–600 %, respectively, and it shows outstanding electromechanical stability with almost unchanged performance under multiple identical tensile strains. Furthermore, the self-powered integrated system can be conveniently used for real-time detection of human motion and small strains. These findings highlight the unlimited application potential of self-powered integrated system in wearable devices.

Selective Ion Sensing Organic Electrochemical Transistors Suitable for Blood Analysis

AbstractOrganic electrochemical transistors (OECTs) have gained considerable attention due to their ability to simultaneously transduce and amplify ion‐based biological signals into electronic signals in bioelectronics. In this study, functionalized OECTs capable of detecting specific ion concentrations in aqueous solution and blood serum are investigated and described. Sodium, the most concentrated cation in the human body, is chosen as the target analyte due to its critical role in maintaining normal bodily functions such as blood pressure, nerve and muscle function, and fluid balance. These sodium ion sensors work at low source‐drain voltage, Vds = 0.4 V and gate voltage, Vg = 0 V, and demonstrate a high sensitivity of 126 μA dec−1 and a high selectivity over different cations. Furthermore, the OECT biosensors are employed to determine sodium concentration in more complex environments and demonstrated a log‐linear response within the physiological range of sodium in blood serum, ranging from 100 to 160 mm. In the final part of the study, the transistor‐based sensor is fabricated in a small‐footprint neural probe configuration and its sensing capability is investigated. These characteristics open up new opportunities for applications in wearable and implantable electronics.

Mulberry Juice-Derived Carbon Quantum Dots as a Cu2+ Ion Sensor: Investigating the Influence of Fruit Ripeness on the Optical Properties

This study synthesized carbon quantum dots (CQDs) with green photoluminescence through a hydrothermal method that utilized mulberry juice as the carbon source. The influence of fruit ripeness on the physical and chemical properties, focusing on the fluorescence spectra, has been explored. Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive X-ray analysis (EDX) showed that there were oxygen-containing groups, and X-ray diffraction (XRD) showed that the carbon quantum dots (CQDs) were graphitic. The results revealed that the CQDs had an average size of around 7.4 nm and 9.7 nm for unripe and ripe mulberry juice, respectively. These CQDs emitted green light at 500 nm and 510 nm in unripe and ripe mulberry juice, respectively, when excited at a wavelength of 400 nm. The prepared CQDs exhibited excitation-dependent photoluminescence (PL) emission behavior, demonstrating their dependence on the excitation light. The impact of fruit ripeness on optical properties was explored by examining fluorescent spectra from different fruits (including tomato and blackberry), demonstrating comparable behaviors observed in mulberry fruit. In addition, the prepared CQDs were utilized as a fluorescent sensor with high specificity to detect Cu2+ ions. The detection limit (DL) for this sensor was determined to be 0.2687 µM, and the limit of qualification (LOQ) is 0.814 µM. The linear range for detection lies between 0.1 and 1 µM. The selectivity of the CQDs towards Cu2+ ions was confirmed by recording the PL response for Cu2+ ions compared to the weak response of other metal ions. According to these results, the CQDs can be applied in various cellular imaging and biology applications, bio-sensing, optoelectronics, and sensors.

Tough, recyclable and biocompatible carrageenan-modified polyvinyl alcohol ionic hydrogel with physical cross-linked for multimodal sensing

Biocompatibility hydrogel conductors are considered as sustainable bio-electronic materials for the application of wearable sensors and implantable devices. However, they mostly face the limitations of mismatched mechanical properties with skin tissue and the difficulty of recycling. In this regard, here, a biocompatible, tough, reusable sensor based on physical crosslinked polyvinyl alcohol (PVA) ionic hydrogel modified with ι-carrageenan (ι-CG) helical network was reported. Through simulating the ion transport and network structure of biological systems, the ionic hydrogels with skin-like mechanical features exhibit large tensile strain of 640 %, robust fracture strength of 800 kPa, soft modulus and high fatigue resistance. Meanwhile, the ionic hydrogel-based sensors possess a high response to strain/pressure over a wide range and could be utilized for multimodal sensing of human activity signals. Benefit from biosafety and temperature reversibility of ι-CG and PVA endow hydrogels with not only biocompatibility, but also meaningfully recyclability. The as-prepared hydrogels could be freely reconstructed into new flexible electronics and safely integrated with the human skin. It could be anticipated that the physically cross-linked ionic hydrogel conductor could expand the options for next-generation bio-based sensors.

Molybdenum disulfide (MoS[formula omitted]) and reduced graphene oxide (rGO) nanocomposite based electrochemical sensor for detecting mercury(II) ions

In this study, a two-dimensional (2D) layered nanocomposite of molybdenum disulfide and reduced graphene oxide (rGO) was synthesized through a facile single-step hydrothermal method. Internal structure and morphological studies have shown that the vertical layered structure of MoS2 has grown over the horizontally aligned layer of reduced graphene oxide. The XRD analysis proved that the structure is multi-layered with 68.8 % crystallinity. Despite the highly crystalline nanocomposite structure, very few defects are also present in the network, as shown through Raman spectroscopy. Further, the presence of CS, RSR, CO, CO, MoO and MoS bonds, identified through XPS, indicates the successful synthesis of the MoS2-rGO nanocomposite. The nanocomposite was further evaluated for its electrochemical properties and applications regarding the sensing of mercury ions. Cyclic voltammetry shows that the oxidation peak current response increased by ∼103 % with the MoS2-rGO modified electrode compared to a bare electrode. The sensor has shown an excellent detection limit (LOD) of 1.6 μM, while the sensitivity and limit of quantification obtained from the sensor are 76.302 μM μA−1 cm−2 and 5.4 μM, respectively. The enhanced sensing performance of the MoS2-rGO modified sensor is attributed to the synergistic effect of MoS2 and rGO. The as-synthesized sensor also exhibits excellent stability, as only a 13% drop in current was observed after 60 days. This work proves that MoS2-rGO possesses enormous potential for developing next-generation heavy metal ion sensors.

Synthesis, Characterization, Photophysical, Lifetime and NLO Studies of Chromenes

Abstract2‐Aminobenzochromenes and dihydropyranchromenes represent a unique class of biologically active compounds. We concentrate on the synthesis of biologically active compounds of chromenes using an environmentally friendly, heterogeneous green Amberlite IRA 400‐Cl resin catalyst. These chromene‐structured compounds enable them to be used as fluorescent sensors. The selected chromenes have been used as metal ion sensors to study their photophysical characteristics.

Transparent, High Stretchable, Environmental Tolerance, and Excellent Sensitivity Hydrogel for Flexible Sensors and Capacitive Pens.

The prospect of ionic conductive hydrogels in multifunctional sensors has generated widespread scientific interest. The new generation of flexible materials should be combined with superior mechanical properties, high conductivity, transparency, sensitivity, good self-restoring fatigue properties, and other multifunctional characteristics, while the current materials are difficult to meet these requirements. Herein, we prepared poly(acrylamide-acrylic acid) (P(AM-AA))/gelatin/glycerol-Al3+ (PG1G2A) ionic conducting hydrogel by one-pot polymerization under UV light. The prepared PG1G2A ionic conductive hydrogel had high tensile strength (539.18 kPa), excellent tensile property (1412.96%), good fast self-recovery and fatigue resistance, high transparency (>80%), excellent moisturizing, and antifreezing/drying properties. In addition, the ionic conductive hydrogel-based strain sensor can respond to mechanical stimulation and generate accurate, stable, and recyclable electrical signals, with excellent sensitivity (GF 5.81). In addition, the PG1G2A hydrogel could be used as flexible wearable devices for monitoring multiple strain and subtle movements of different body parts at different temperatures. Interestingly, the PG1G2A hydrogel capacitive pen embedded in the mold can be used to write and draw on the screen of a phone or tablet. This new multifunctional ionic conducting hydrogel shows broad application prospects in E-skin, motion monitoring, and human-computer interaction in extreme environments.

Electrochemical determination of cadmium ions in biological and environmental samples using a newly developed sensing platform made of nickel tungstate-doped multi-walled carbon nanotubes

Simple and rapid analysis of cadmium ion in environmental and biological samples is of great importance due to the severe toxicity caused by this heavy metal. In the present work, nickel tungstate (NiWO4) dispersion was mixed with multi-walled carbon nanotubes (MWCNTs) to obtain a homogenous composite of (NiWO4/MWCNTs) which was assigned as carbon paste electrode modifier. The composite was fully characterized using various characterization techniques including X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Thermo-Gravimetric Analysis (TGA) and Fourier Transform InfraRed (FTIR). The electrochemical redox reactions of cadmium (II) ions at the modified electrode interface were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and linear sweep voltammetry (LSV). Effective parameters on the electro-analysis assay performance including the electrode composition, types of electrolyte, scan rate and pH were tested to achieve the best effective optimum conditions. Accordingly, a linear relation of cadmium ions was achieved in the concentration range 50–450 µM with limit of detection of 0.12 µM. Besides, the proposed electrode was successfully used to monitor trace amounts of cadmium ions in various real samples.Graphical abstractSchematic illustration of synthesis process of NiWO4/MWCN nanocomposite and its application as high-performance cadmium ion sensors

Zinc-Induced Fluorescence Turn-On in Native and Mutant Phycoerythrobilin-Binding Orange Fluorescent Proteins.

Cyanobacteriochrome (CBCR)-derived fluorescent proteins are a class of reporters that can bind bilin cofactors and fluoresce across the ultraviolet to the near-infrared spectrum. Derived from phytochrome-related photoreceptor proteins in cyanobacteria, many of these proteins use a single small GAF domain to autocatalytically bind a bilin and fluoresce. The second GAF domain of All1280 (All1280g2) from Nostoc sp. PCC7120 is a DXCF motif-containing protein that exhibits blue-light-responsive photochemistry when bound to its native cofactor, phycocyanobilin. All1280g2 can also bind non-photoswitching phycoerythrobilin (PEB), resulting in a highly fluorescent protein. Given the small size, high quantum yield, and that unlike green fluorescent proteins, bilin-binding proteins can be used in anaerobic organisms, the orange fluorescent All1280g2-PEB protein is a promising platform for designing new genetically encoded metal ion sensors. Here, we show that All1280g2-PEB undergoes a ∼5-fold reversible zinc-induced fluorescence enhancement with a blue-shifted emission maximum (572 to 517 nm), which is not observed for a related PEB-bound GAF from Synechocystis sp. PCC6803 (Slr1393g3). Zn2+ significantly enhances All1280g2-PEB fluorescence across a biologically relevant pH range from 6.0 to 9.0, with pH-dependent dissociation constants from 1 μM to ∼20-80 nM. Site-directed mutants aiming to sterically decrease and increase access to PEB show a decreased and similar amount of zinc-induced fluorescence enhancement. Mutation of the cysteine residue within the DXCF motif to alanine abolishes the zinc-induced fluorescence enhancement. Collectively, these results support the presence of a unique fluorescence-enhancing Zn2+ binding site in All1280g2-PEB likely involving coordination to the bilin cofactor and requiring a nearby cysteine residue.

The source of electrons at comet 67P

ABSTRACT We examine the origin of electrons in a weakly outgassing comet, using Rosetta mission data and a 3D collisional model of electrons at a comet. We have calculated a new data set of electron-impact ionization (EII) frequency throughout the Rosetta escort phase, with measurements of the Rosetta Plasma Consortium’s Ion and Electron Sensor (RPC/IES). The EII frequency is evaluated in 15-min intervals and compared to other Rosetta data sets. EII is the dominant source of electrons at 67P away from perihelion and is highly variable (by up to three orders of magnitude). Around perihelion, EII is much less variable and less efficient than photoionization at Rosetta. Several drivers of the EII frequency are identified, including magnetic field strength and the outgassing rate. Energetic electrons are correlated to the Rosetta-upstream solar wind potential difference, confirming that the ionizing electrons are solar wind electrons accelerated by an ambipolar field. The collisional test particle model incorporates a spherically symmetric, pure water coma and all the relevant electron-neutral collision processes. Electric and magnetic fields are stationary model inputs, and are computed using a fully kinetic, collision-less Particle-in-Cell simulation. Collisional electrons are modelled at outgassing rates of Q = 1026 s−1 and Q = 1.5 × 1027 s−1. Secondary electrons are the dominant population within a weakly outgassing comet. These are produced by collisions of solar wind electrons with the neutral coma. The implications of large ion flow speed estimates at Rosetta, away from perihelion, are discussed in relation to multi-instrument studies and the new results of the EII frequency obtained in this study.

A Summary of Recent Developments in Potentiometric Sensor Arrays

With upgrades in as far as possible and selectivity of ISEs, the presentation of new materials, new detecting ideas (from regular potentiometric to dynamic electrochemistry draws near), and more profound hypothetical getting it and displaying of the potentiometric reactions of ISEs, potentiometric in light of particle specific cathodes (ISEs) has encountered a renaissance. Ion sensors based on solid-state or polymeric membranes are currently available and can be used in sensor array formats for a variety of analytical applications. Coated wire electrodes (CWE), ion-sensitive field-effect transistors (ISFETs), and light-addressable potentiometric sensors (LAPS) are just a few of the strategies that have been developed to construct and use potentiometric sensor arrays based on various transduction principles. This review aims to provide a critical overview of these strategies. After reading recent papers on the development and applications of potentiometric sensor arrays, several issues and trends have been identified.

Liquid-Free, Self-Repairable, Recyclable, and Highly Stretchable Colorless Solid Ionic Conductive Elastomers for Strain/Temperature Sensors.

Solid-state ionic conductive elastomers (ICEs) can fundamentally overcome the disadvantages of hydrogels and ionogels (their liquid components tend to leak or evaporate), and are considered to be ideal materials for flexible ionic sensors. In this study, a liquid-free ionic polyurethane (PU) type conductive elastomer (ICE-2) was synthesized and studied. The PU type matrix with microphase separation endowed ICE-2 with excellent mechanical versatility. The disulfide bond exchange reaction in the hard phase and intermolecular hydrogen bonds contributed to damage repairing ability. ICE-2 exhibited good ionic conductivity (2.86×10-6 S/cm), high transparency (average transmittance >89 %, 400~800 nm), excellent mechanical properties (tensile strength of 3.06 MPa, elongation at break of 1760 %, and fracture energy of 14.98 kJ/m2 ), appreciable self-healing ability (healing efficiency >90 %), satisfactory environmental stability, and outstanding recyclability. The sensor constructed by ICE-2 could not only realize the perception of temperature changes, but also accurately and sensitively detect various human activities, including joint movements and micro-expression changes. This study provides a simple and effective strategy for the development of flexible and soft ionic conductors for sensors and human-machine interfaces.

Core–shell- shell structured P(Ani-co-Py)/NiF-grafted-(Go-PPD)-PPy nanocomposites prepared via two steps polymerization of conducting polymer for sensitive Tl3+detection

In this research, a newly developed structure consisting of a shell made of (Graphene oxide-Paraphenylenediamine)/Polypyrrole (Go-PPD)-PPy was successfully synthesized on a binary poly(aniline-co-o-pyrrole)/NiFe2O4 core-shell nanocomposite, known as P(Ani-co-Py)/NiF NCs. The synthesis process involved a two-step approach, starting with the in-situ oxidative polymerization of the copolymer P(Ani-co-Py) on NiF nanoparticles (NPs). This was followed by a subsequent in-situ oxidative polymerization of (Go-PPD)-PPy on the P(Ani-co-Py)/NiF core-shell NCs, resulting in the formation of PPy-(Go-PPD)/P(Ani-co-Py)/NiF NCs with a core-shell-shell structure. In this method, the developed sensor designed specifically for Tl3+ demonstrated high effectiveness and reliability in detecting Tl3+ ions within a phosphate buffer medium. During the fabrication process of the sensor probe, the stability of the synthesized PPy-(Go-PPD)/P(Ani-co-Py)/NiF NCs on a glassy carbon electrode (GCE) was enhanced significantly by incorporating nafion, a 5% suspension in ethanol. A calibration curve was established by drawing the current toward the concentration of Tl3+, showing a linear relationship. By looking at the maximum linear portion of the calibration curve, a linear dynamic range of 0.1 nM to 0.01 mM was determined. Sensor sensitivity has been calculated as 1.06 µAµM−1cm−2, by setting the slope of the calibration curve and GCE (the surface area of the glassy carbon electrode), which was measured as 0.0316 cm2. The lower limit of detection (LOD) was determined to be 92.09±4.60 pM based on a signal-to-noise ratio of 3. Limit of quantification (LOQ) is calculated as 279.06 pM from 10*(LOD)/3.3. Finally, the proposed Tl3+ ion sensor's performance was validated by analyzing real environmental samples, and satisfactory results were obtained.

Biomimetic Ion Channel Regulation for Temperature-Pressure Decoupled Tactile Perception.

The perception of temperature and pressure of skin plays a vital role in joint movement, hand grasp, emotional expression, and self-protection of human. Among many biomimetic materials, ionic gels are uniquely suited to simulate the function of skin due to its ionic transport mechanism. However, both the temperature and pressure sensing are heavily dependent on the changes in ionic conductivity, making it impossible to decouple the temperature and pressure signals. Here, a pressure-insensitive and temperature-modulated ion channel is designed by synergistic strategies for gel skeleton's compact packing and ultra-thin structure, mimicking the function of the temperature ion channel in human skin. This ion-confined gel can completely suppress the pressure response of the temperature sensing layer. Furthermore, a temperature-pressure decoupled ionic sensor is fabricated and it is demonstrated that the ionic sensor can sense complex signals of temperature and pressure. This novel and effective approach has great potential to overcome one of the current barriers in developing ionic skin and extending its applications.

Self-powered optical ion sensor array based on potentiometric probes coupled to electronic paper

This work describes a direct optical readout of an ion-selective potentiometric sensing array without an external power supply. Electronic paper (e-paper) was chosen as the signal transducer owing to its fast response on the order of seconds and its wide dynamic range of about 1.5 V. The capacitive character of the display allows one to observe the optical response at zero current, which is a desired condition for the potentiometric measurement. An applied potential of 1 V gives a transient charge flow of about 11 μC for the e-paper to exhibit a maximal intensity change. The cathodes of three different pixels of the e-paper were connected to three different ISEs responsive to Na+, K+, and Ca2+, while their common anode was connected to the shared reference electrode (RE). In this manner, each pixel is mapped to the behavior of one sensor, making it possible to detect multiple ions with an e-pixel array. The sensor configuration gave quantitative information on Na+, K+, and Ca2+ from 10−5 M to 10−1 M by analyzing the RGB information of the pixels. The e-paper exhibited a stable response within half a minute, much faster than previously established electrochromic material transducers such as Prussian Blue (PB). With this approach we successfully carried out multi-ion concentration sensing without external power, which is potentially attractive for applications in environmental monitoring, clinical assays and wearable sensing devices.

Resistive Ion Sensors Based on Metal–Oxide–Semiconductor Nanostructures Formed by Heating Metal Foil

Resistive Ion Sensors Based on Metal–Oxide–Semiconductor Nanostructures Formed by Heating Metal Foil

Evaluation of thallium ion as an effective ion in human health using an electrochemical sensor

Exposure to thallium (Tl), a noxious heavy metal, poses significant health risks to both humans and animals upon ingestion. Therefore, monitoring Tl levels in the environment is crucial to prevent human exposure and reduce the risk of developing severe health problems. This paper presents the development of a highly sensitive Tl ions sensor through surface modification of a glassy carbon electrode with a nanocomposite comprising MnO2 magnetic sepiolite and multi-walled carbon nanotubes (MnO2@Fe3O4/Sep/MWCNT/GCE). Multiple methodologies were employed to assess the performance of the newly developed sensor. By employing square wave anodic stripping voltammetry (SWASV) to optimize the measurement conditions, notable enhancements were observed in the stripping peak currents of Tl (I) on the MnO2@Fe3O4/Sep/MWCNT/GCE surface. The effectiveness of the nanocomposite in facilitating electron transfer between the Tl (I) ions (guest) and the electrode (host) was demonstrated from the enhanced signals observed at the different modified electrode surfaces under optimal conditions. The developed sensor displayed a wide linear range of 0.1–1500 ppb for Tl (I) and a low detection limit of 0.03 ppb for Tl (I). It was found to be selective for Tl (I) ions while remaining unaffected by interfering non-target ions in the presence of the target ions. Despite its simple preparation procedure, the modified electrode exhibited high stability and excellent reproducibility for measuring Tl (I). The outstanding electroanalytical performances of the MnO2@Fe3O4/Sep/MWCNT/GCE electrode enabled its successful use as an ultrasensitive sensor for determining trace amounts of Tl in environmental samples.

Synthesis of 4-(1-(2-(2,4-dinitrophenyl)hydrazineylidene)-5-phenylpenta-2,4-dien-1-yl)-1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole as optical sensor for the toxic heavy metal ions in an aqueous medium

Heavy metal ions represented as highly toxic pollutants for the environment. In the search for new optical sensors for heavy metals, here, new organic linker [4-(1-(2-(2,4-dinitrophenyl)hydrazineylidene)-5-phenylpenta-2,4‑dien-1-yl)-1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole] was prepared in 87% yield by simple and facile method. The techniques of synthesis follow the formation of chalcone then condensation with hydrazine moiety to perform hydrazone derivatives. It was synthesized from addition of 1-(1-(4-Methoxyphenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-5-phenylpenta-2,4‑dien-1-one to 2,4-dinitrophenylhdrazine. The chemical structure of prepared linker was established by the IR and NMR spectral data in addition to single-crystal X-ray crystallography. The new linker was used for detection of various metal ions (Cu2+, Zn2+, Cr3+, Co2+, Cd2+, and Hg2+). Interestingly, the new linker showed highly detection level and selectivity toward Hg2+ions. The color of the Hg2+ ions solution was turned from colorless to green when adding the title compound performed excellent naked-eye detection. The binding stoichiometry of the linker to the Hg2+ ions was found to be 1:1, which was confirmed by Job plot. For industrial application, the new linker was mixed with filter paper and used for detection of Hg2+ions. The new fabricated filter paper was identified using scanning electron microscopy (SEM). The present fabricated filter paper produced naked eye colorimetric detection of Hg2+ions.