Detection Of CO Research Articles

Mid-infrared telemetry sensor based calibration gas cell for CO detection using a laser wavelength locking technique

A CO telemetry sensor was designed based on the quantum cascade laser-tunable diode laser absorption spectroscopy (QCL-TDLAS) technology using the fundamental frequency absorption band of CO gas molecules at 4.58 μm. A Fresnel lens with a diameter of 250 mm is utilized to achieve a large area of light collection. The application of light beam tracking method realizes the visualization of telemetry optical path and improves the target tracking capability of telemetry system. Laser wavelength locking technique are investigated to lock the sensor wavelength, thus solving the wavelength drift caused by environmental temperature changes. The second harmonic/laser power signal technique based on wavelength modulated spectroscopy(2f/LPS-WMS) is used to reduce the interference of background noise and laser power intensity by normalizing the second harmonic (2f) with the laser power signal (LPS). Several gas telemetry experiments were performed to verify the sensor performance and the positive linear response of the sensor for CO telemetry was demonstrated. The sensor was tested for stability for approximately 1 h and the Allan -Werle deviation was analyzed. The minimum limit of detection (LOD) of the sensor was 23.07 ppb·m with an averaging time of 62 s. The sensor was reportedly deployed outdoors for the measurement of CO concentration in atmospheric environments.

Extending Ag Nanoparticles as Colorimetric Sensor to Industrial Zinc Electrolyte for Cobalt Ion Detection

The direct and rapid determination of trace cobalt ion (Co2+) in the electrolyte of zinc smelting plants is urgently needed but is impeded by the severe interference of extremely high-concentration zinc ions in the solution. Herein, colorimetric detection of Co2+ by the polyvinylpyrrolidone functionalized silver nanoparticles (PVP-AgNPs) is realized in solutions with the Zn/Co ratio being high, up to (0.8-5) × 104, which is located within the ratio range in industrial solution. The high concentration of Zn2+ induces a strong attenuation of Co2+-related signals in ultraviolet-visible (UV-vis) extinction spectra; nevertheless, a good linear range for detecting 1-6 mg/L Co2+ in 50 g/L Zn2+ solution is still acquired. The strong anti-interference toward other metal ions and the mechanism understanding for trace Co2+ detection in such a high-concentration Zn2+ solution are also revealed by systematic analysis techniques. The results extend the AgNPs as colorimetric sensors to industrial solutions, providing a new strategy for detecting trace-metal ions in industrial plants.

Highly sensitive and selective sensing-performance of 2D Co-decorated phthalocyanine toward NH3, SO2, H2S and CO molecules

Developing excellent sensing-materials for detecting and monitoring toxic gases in the air is significant for environmental monitoring and industrial emission evaluation. Herein, the first-principles calculations were employed to systematically investigate the adsorption characteristics of twelve different gas molecules (NH3, NO, NO2, SO2, H2S, CO, CO2, CH4, H2O, H2, O2, N2) on the two-dimensional phthalocyanine (Pc) and Co decorated phthalocyanine (CoPc), the electronic properties of various adsorption systems and their sensing-mechanism were also elucidated. The results show that the toxic NH3, NO, NO2, SO2, H2S are chemically adsorbed on the pristine Pc surface, whereas the poor sensitivity of Pc monolayer makes it not suitable to be a sensing-material. By contrast, the CoPc monolayer exhibits the appropriate adsorption strength toward the six poisonous gases (NH3, NO, NO2, SO2, H2S, CO), which is detailedly explained by the analysis of charge transfer, charge density difference and density of states. Moreover, the CoPc monolayer possesses high selectivity to those six gases even if it is in a humid environment. The CoPc monolayer also has excellent sensitivity for those toxic gases due to the obvious variations of bandgap, magnetic moment or work function. Additionally, the recovery time of NH3, SO2, H2S and CO is estimated to be about 3.91 min, 0.02 s, 24.19 ns and 226.38 ns at room temperature, respectively. Consequently, the CoPc monolayer based gas sensor has a great potential application for the NH3, SO2, H2S and CO detection.

Hierarchical NiO/TiO2 heterojuntion-based conductometric hydrogen sensor with anti-CO-interference

Constructing a heterojunction is an effective way to improve the gas sensing properties of metal oxide semiconductors. In this work, a hydrogen sensor containing hierarchical and porous NiO/TiO2 heterojunction bilayer structure was designed. The top layer is formed by the NiO nanowalls grown along the [220] direction with exposed (111) facets, and the bottom layer is formed by the [002] oriented TiO2 nanorod arrays. The exposed high energy crystal surfaces of NiO and TiO2, together with the adapted surface depletion region, induced by the formation of the heterojunction, enable the hydrogen sensor to have both a wide detection range and a much higher response to hydrogen than single layer materials. With the optimized size of the pores existing between the walls, the hydrogen sensor shows excellent prevention to interference from CO. Both the gas diffusion regulated by the porous structure and the surface interaction between H2/CO and O2- controlled by the heterojunction barrier contribute to the distinctive detection of H2 and CO at room temperature (25 ℃ ± 2 ℃).

In situ infrared CO detection using silver loaded EMT zeolite films.

Ag cluster catalyst-based oxidation of CO to CO2 is an important way to remove CO at low temperatures. However, the instability of silver clusters seriously limits the catalytic application. Herein, sub-nanosized EMT zeolite nanoparticles served as Ag cluster carriers with high selectivity, low coordination, and unsaturated atom active sites. The silver clusters with sub-nanometer size can be controlled with different charge states and loading rates. A detection film with 500 nm was further prepared by assembling the Ag-EMT composites with a small amount of Nalco as an adhesive. For CO detection, a completely enclosed gas sensing device based on in situ infrared spectroscopy was employed without air interference. CO was accurately introduced into the detection chamber and catalysed into CO2 by silver loaded EMT zeolite films, and the whole process was accurately recorded by infrared spectroscopy. CO with a detection range of 2-50 ppm was realized, showing great application potential in gas monitoring.

Simultaneous Detection of CO<sub>2</sub> and N<sub>2</sub>O Based on Quartz-enhanced Photothermal Spectroscopy by Using NIR and MIR Lasers

Simultaneous Detection of CO<sub>2</sub> and N<sub>2</sub>O Based on Quartz-enhanced Photothermal Spectroscopy by Using NIR and MIR Lasers

The emergence and advancement of Tsuji-Trost reaction triggered carbon monoxide recognition and bioimaging.

Considering that carbon monoxide is both a vital gasotransmitter and an obnoxious gas, tremendous efforts have been dedicated toward its recognition through various methods. However, the fluorescent light-up approach through the exploration of optical markers remains one of the most convenient methods owing to its several advantages. Amongst the different approaches towards the development of CO responsive optically active molecular markers, the Tsuji-Trost reaction-based CO recognition strategy has remained one of the most significant areas of interest across researchers working in this field. However, there have been no attempts to exclusively summarize the commendable work done in this area yet. The current review, therefore, attempts to summarize the developments of various optical probes following this reaction strategy until the year 2022. This review provides detailed mechanistic insights into the Tsuji-Trost mediated CO detection strategy. Besides, discussions on the strategic development and employment of probes based on various allyl derivatives - allyl carbamate/carbonate/ethers - will provide a thorough understanding of the detection method. The significant advancements of the Tsuji-Trost reaction as an interesting strategy that is accepted and extensively explored for monitoring CO in various media including air, aqueous solutions and living systems have been elaborately discussed. Various potential applications and utilization of these developed fluorogenic probes for tracing CO in different living systems have been examined systematically. Moreover, monitoring of exogenous/endogenous CO levels, modulation of intracellular CO concentration under various induced conditions and bioimaging of CO in in vivo models have also been detailed here. Briefly, this review summarizes the current prospects of this detection method and the future directions in related fields.

Dual Activation and Photocatalyst-Induced Selective Detection in Defect Tuned Pd–ZnO Thin Films for Low ppm Detection of CH and CO

The selectivity of CO and CH4 remains a hurdle to researchers working on metal-oxide-based sensors, as the sensing mechanism is analogous for both gases. With this objective, an attempt has been made to realize selective sensing of CH4 (up to 1 ppm) and CO (up to 1 ppm) by introducing a selective photocatalyst layer (Zn5(OH)8Cl2.H2O) on Pd–ZnO. It has been noticed that the incorporation of a photocatalytic layer is found to be highly efficacious in providing the sensor with a strong absorption reaction and propelling the surface conversion kinetics. The role of dual activation and photocatalytic activity in selectivity along with tunability is also explored in this work. The dual activation incorporates the benefits of both temperature and optical excitation on metal-oxide-based sensors, highlighting the innumerable advantages and nullifying the disadvantages of both methods. Tunable and selective sensing with a response time/recovery time of 40 s is explicated. The method for improving the sensing performance of Pd–ZnO–photocatalyst-based nanostructures in terms of repeatability and cross sensitivity with respect to 1 ppm of CO, 1 ppm of CH4, 1 ppm of NH3, 250 ppm of CO, and 40% of O2 is discoursed. It has been observed that the sensor with a sensitivity of 23%/ppm for CH4 and 93%/ppm for CO with a minimum baseline drift of less than 3% is achieved. The long-term stability and repeatability of dual-activated sensors are also verified, and less than 3% change has been noticed. The work can be extended for the selectivity of other metal oxides as well.

Data-assimilated time-lapse visco-acoustic full-waveform inversion: Theory and application for injected CO2 plume monitoring

Continuous seismic monitoring for quantifying CO2 plume migration and detection of any potential leakages in the subsurface is essential for the security of long-term anthropogenic carbon dioxide geologic storage. Traditional time-lapse full-waveform inversion (TLFWI) methods aim to map the CO2 distribution by estimating seismic velocity changes, but recent studies find that CO2-induced attenuation is an important complement to seismic velocity for tracking the CO2 plumes and even quantifying the CO2 saturation. We have developed a novel data-assimilated TLFWI method to construct high-resolution time-lapse velocity and attenuation changes from dense time-lapse monitoring data. This method consists of two theoretical developments: visco-acoustic full-waveform inversion (QFWI) and multiparameter hierarchical matrix-powered extended Kalman filter (mHiEKF). The method is capable of (1) posing temporal constraints to retrieve time-lapse information from dense monitoring data by using mHiEKF, (2) accurately recovering high-spatial-resolution velocity and attenuation perturbations using first-order equation system-based QFWI, and (3) providing the model uncertainty by estimating their model standard deviation. With numerical examples, we first find the effectiveness of the new QFWI on estimating accurate velocity and attenuation models simultaneously. Then, a CO2 leakage case and a realistic Frio-II CO2 monitoring case are presented to find the advantages and applicability of our data-assimilated QFWI method for estimating time-lapse changes using dense time-lapse monitoring surveys. By assimilating time-lapse seismic monitoring data over time, our data-assimilated QFWI method can improve the resolution of velocity and attenuation changes and decrease their model uncertainties.

Suppressing carbon corrosion via mechanically mixing transition metal phosphide clusters: a comparative in situ study in alkaline media

Using differential electrochemical mass spectrometry (DEMS), carbon oxidation monitoring in alkaline media with sensitive detection of CO2 is enabled and a simple strategy to suppress carbon corrosion is offered.

De Novo Construction of Fluorophores via CO Insertion-Initiated Lactamization: A Chemical Strategy toward Highly Sensitive and Highly Selective Turn-On Fluorescent Probes for Carbon Monoxide.

Extensive studies in the last few decades have led to the establishment of CO as an endogenous signaling molecule and subsequently to the exploration of CO's therapeutic roles. In the current state, there is a critical conundrum in CO-related research: the extensive knowledge of CO's biological effects and yet an insufficient understanding of the quantitative correlations between the CO concentration and biological responses of various natures. This conundrum is partially due to the difficulty in examining precise concentration-response relationships of a gaseous molecule. Another reason is the need for appropriate tools for the sensitive detection and concentration determination of CO in the biological system. We herein report a new chemical approach to the design of fluorescent CO probes through de novo construction of fluorophores by a CO insertion-initiated lactamization reaction, which allows for ultra-low background and exclusivity in CO detection. Two series of CO detection probes have been designed and synthesized using this strategy. Using these probes, we have extensively demonstrated their utility in quantifying CO in blood, tissue, and cell culture and in cellular imaging of CO from exogenous and endogenous sources. The probes described will enable many biology and chemistry labs to study CO's functions in a concentration-dependent fashion with very high sensitivity and selectivity. The chemical and design principles described will also be applicable in designing fluorescent probes for other small molecules.

Polyethyleneimine-Starch Functionalization of Single-Walled Carbon Nanotubes for Carbon Dioxide Sensing at Room Temperature.

There is an ever-growing interest in the detection of carbon dioxide (CO2) due to health risks associated with CO2 emissions. Hence, there is a need for low-power and low-cost CO2 sensors for efficient monitoring and sensing of CO2 analyte molecules in the environment. This study reports on the synthesis of single-walled carbon nanotubes (SWCNTs) that are functionalized using polyethyleneimine and starch (PEI-starch) in order to fabricate a PEI-starch functionalized SWCNT sensor for reversible CO2 detection under ambient room conditions (T = 25 °C; RH = 53%). Field-emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy are used to analyze the physiochemical properties of the as-synthesized gas sensor. Due to the large specific surface area of SWCNTs and the efficient CO2 capturing capabilities of the amine-rich PEI layer, the sensor possesses a high CO2 adsorption capacity. When exposed to varying CO2 concentrations between 50 and 500 ppm, the sensor response exhibits a linear relationship with an increase in analyte concentration, allowing it to operate reliably throughout a broad range of CO2 concentrations. The sensing mechanism of the PEI-starch-functionalized SWCNT sensor is based on the reversible acid-base equilibrium chemical reactions between amino groups of PEI and adsorbed CO2 molecules, which produce carbamates and bicarbonates. Due to the presence of hygroscopic starch that attracts more water molecules to the surface of SWCNTs, the adsorption capacity of CO2 gas molecules is enhanced. After multiple cycles of analyte exposure, the sensor recovers to its initial resistance level via a UV-assisted recovery approach. In addition, the sensor exhibits great stability and reliability in multiple analyte gas exposures as well as excellent selectivity to carbon dioxide over other interfering gases such as carbon monoxide, oxygen, and ammonia, thereby showing the potential to monitor CO2 levels in various infrastructure.

Reusable carbon dot/chitin nanocrystal hybrid sorbent for the selective detection and removal of Cr(VI) and Co(II) ions from wastewater

The last few decades have seen a dramatic increase in heavy metal ions in industrial wastewater, especially Cr6+ and Co2+ ions, which have been shown to adversely affect human health; thus, there is a great need for their removal. Existing removal methods are time-consuming, expensive, and require high technical skills; therefore, there exists a need for a quick, simple, and cost-effective method. Chitin was selected from natural materials (shrimp waste), and an inexpensive, biodegradable, fluorescent carbon dot/chitin nanocrystal (C-dot/ChNC) sorbent for the simultaneous detection and removal of heavy metal ions from wastewater was synthesized from it. C-dot/ChNC shows high selectivity and sensitivity to Cr6+ and Co2+ ions and has high chromium(VI) and cobalt(II) adsorption capacities. These ions are weakly adsorbed on the C-dot/ChNC surface and are easily removed during regeneration, showing high cyclability. Thus, C-dot/ChNC is a viable sorbent for the removal of heavy metal ions during wastewater treatment.

Compact QEPAS CO2 sensor system using a quartz tuning fork-embedded and in-plane configuration

A quartz-enhanced photoacoustic spectroscopy (QEPAS) system was developed based on a novel quartz tuning fork-embedded, and in-plane QEPAS technique, while increasing the efficiency of assembly alignment with the aid of 3D printing technology. In this paper, it was verified that the simplified numerical model enabled rapid optimization of the dimensions of the acoustic micro-resonator (AmR), and this was validated by experimental results. The optimized results are as follows: outer diameter = 3.2 mm, inner diameter = 0.5 mm, length = 6.77 mm. The acoustic transducer used a commercial quartz tuning fork with a resonance frequency of 30.69 kHz. After optimizing the laser wavelength modulation amplitude and the dimensions of the AmR, a minimum CO2 detection limit of 1.06 ppm was obtained, corresponding to a normalized noise equivalent absorption of 5.5 × 10−9 cm−1 WHz−1/2.

Trigeminal Sensitivity in Patients With Allergic Rhinitis and Chronic Rhinosinusitis

Allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP) are of high importance in otorhinolaryngology. Some of their symptoms are related to changes in the nasal trigeminal sensitivity. The aim of this study was to compare nasal trigeminal sensitivity in patients with AR, CRSwNP, and healthy controls (HC). A total of 75 individuals participated (age 19-78 years; 34 AR, 10 CRSwNP and 31 HC). Olfactory function was determined using the extended Sniffin' Sticks test battery. Trigeminal sensitivity was assessed with CO2 detection thresholds. Trigeminal negative mucosal potentials (NMP) and EEG-derived event-related potentials (ERP) were recorded in response to selective olfactory (phenylethyl alcohol) and trigeminal (CO2 ) stimuli using high-precision air-dilution olfactometry. In comparison to HC, AR patients had lower CO2 thresholds, also reflected in shorter peak latencies in NMP and trigeminal ERP measurements. CRSwNP patients had a decreased sensitivity for trigeminal stimuli, also reflected in prolonged trigeminal ERP latencies, and reduced olfactory function compared to HC. AR patients seemed to be more sensitive to trigeminal stimuli than CRSwNP patients. Importantly, the differences could be shown on psychophysical and electrophysiological levels. The changes in trigeminal sensitivity appear to be present already at the level of the respiratory epithelium. The differences between the two groups may depend on the specific inflammatory changes accompanying each disorder, the degree of inflammatory activity, or duration of the inflammatory disorder. However, because the sample sizes are relatively small, these results need to be confirmed in the future studies with larger groups. 4 Laryngoscope, 133:654-660, 2023.

Surface modification of In2O3 porous nanospheres with Au single atoms for ultrafast and highly sensitive detection of CO

The growing concern on environmental issues has stimulated intensive research interest on the gas sensors based on metal oxide semiconductor (MOS) due to their superiority in monitoring gaseous pollutants. In this context, developing advanced MOS sensors that can realize fast and selective detection of various flammable and harmful gases is of greatly desired, but still remains challenging. Here, we propose an Au single-atom sensitization strategy to boost the CO sensing performance of In2O3. To expound it, Au single atom catalyst (Au1) was prepared from an iced photochemical reduction method and then modified on In2O3 porous nanospheres (PNSs) to obtain the hybrid Au1/In2O3 gas sensing material. Benefiting from the outstanding spillover and catalytic effects of Au1, the best Au1/In2O3-2 show superior CO sensing performances to the bare In2O3 counterpart, especially of lower optimal working temperature (OWT: 360 °C vs 380 °C), higher sensitivity (0.032/ppm vs 0.003/ppm to 10–100 ppm CO), and faster response/recovery speed (2/10 s vs 47/205 s). Besides, the Au1/In2O3-2 sensor also shows good selectivity and stability. These features make the present Au1/In2O3 PNS a promising candidate for fabricating high-performance CO sensor. Our research demonstrates that surface functionalization with single-atom metal catalyst is a promising strategy to develop advanced MOS sensor.

A novel approach for ultrafast and highly sensitive carbon monoxide gas sensor based on PEDOT/GO nanocomposite

An ultrafast and highly sensitive carbon monoxide gas sensor based on PEDOT/GO nanocomposites has been addressed in this work. A new approach was utilized to materialize PEDOT/GO via a straightforward and inexpensive polymerization in the presence of GO. Many characterization techniques, including FE-SEM, AFM, TGA, XRD, FTIR, Raman spectroscopy, and UV–Vis spectroscopy, have been utilized to confirm the successful formation of the PEDOT/GO nanocomposite. Moreover, the chemosensitivity modality has been used to measure the materials’ resistivity and sensing performance. The PEDOT/GO-based sensor exhibits excellent sensitivity when exposed to a wide range of CO concentrations, from 20 ppm to 270 ppm. Our experimental outcomes demonstrated that incorporating PEDOT into GO enhanced the sensor sensitivity (from 16% for pure PEDOT to 44% for composite), which resulted in quick response/recovery times (43 s/42 s) and exceptional long-term stability at room temperature. Based on the results of this work, it seems likely that the proposed sensor, with its low cost, simple development process, and excellent sensing performance, could be a good candidate for real-time CO detection.

Computational study of surface orientation effect of wurtzite GaN on CH4 and CO sensing mechanism

The adsorption behaviors of gas molecules CH4 and CO on polar (0001), (000–1) facets and nonpolar (10-10), (11–20) facets of wurtzite GaN were explored in details by first-principles calculations. Among these important low-index facets, CH4 on the (0001) facet exhibits the lowest adsorption energy of −1.57 eV, signifying the highest density of adsorbed CH4 molecules under the same methane concentration in air. Meanwhile, the C–H bond is weakened revealed by the bond length elongation from 1.0956 Å to 1.1020 Å during adsorption, consistent with charge redistribution results. The adsorption energies for CO on the (0001) and (000–1) facets are calculated to be −2.17 eV and −3.89 eV, much lower than those on nonpolar facets. Obviously, the corresponding C–O bond is activated during adsorption, proved by the bond length elongated from 1.1531 Å to 1.2003 Å and 1.1715 Å, respectively, in line with charge redistribution results. Particularly, the co-adsorption simulation verifies the surface redox reaction between CO and O2 on + c-plane GaN. Therefore, we predict superior performance of (0001) GaN in detection for high concentration CH4 and (000–1) GaN in selective detection for low concentration CO.

Anthropogenic greenhouse CO2 gas sensor based on glassy carbon modified with organoclay/ polypyrrole-alginate nanocomposites in brackish water and seawater

Schematic presentation of the detection of CO 2 using a glassy carbon sensor (GCS) and modified glassy carbon sensor (MGCS) based on organoclay/polypyrrole-alginate (OC/Ppy-A) nanocomposite via cyclic voltammetry. • An anthropogenic greenhouse CO 2 gas sensor was successfully fabricated. • The sensor exhibited remarkable conductivity and electrocatalytic activity. • Low detection limits and a wide linearity range were observed. • The sensor was successfully applied to detect CO 2 in brackish and seawater samples. An increase in the amount of greenhouse gases around the Earth’s atmosphere generated by emissions through various sources creates a huge problem for the near future because of global warming and the consequent climate changes. This study fabricated an organoclay/polypyrrole-alginate (OC/Ppy-A) nanocomposite-modified glassy carbon sensor (MGCS), which was used for the sensitive estimation of anthropogenic greenhouse gas (CO 2 ). The efficiency of the developed sensor was investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Compared with the bare glassy carbon sensor (GCS), the developed MGCS exhibited a fivefold superior CV signal for the recognition of the redox-active solution of potassium ferricyanide (K 3 [Fe(CN) 6 ]). The CV signal currents of the redox reaction of (K 3 [Fe(CN) 6 ]) were changed by changing the amount of CO 2 molecules in the measured samples. The oxidation signal of (K 3 [Fe(CN) 6 ]) linearly correlated with the CO 2 concentration in the separate ranges of 0.05–0.25 ppm (0.595–2.98 µM) and 0.25–3.5 ppm (2.98–41.67 µM) with limits of detection (S/N = 3) of 0.0165 ppm (0.196 µM, 40.569 μA/ppm) and 0.0825 ppm (0.982 µM, 1.751 μA/ppm). Additionally, the developed electrochemical MGCS exhibited appropriate repeatability, reproducibility, and stability. The proposed sensor was successfully applied for the determination of CO 2 in brackish and seawater samples in Egypt.

Development of sulphonated co-polyimide based sensor for metal ions detection in aqueous media

• Sulphonated co-polyimide (OBM-20) was synthesized by thermal imidization. • UV-Vis spectroscopy was carried out to evaluate the sensing behaviour of OBM-20. • Sensor showed appreciable increase in absorption intensity upon interaction with metal ions. • Sensor detected the nM concentration of metal ions under optimized conditions. This study reports a facile approach towards sensing properties of hydrophilic sulphonated co-polyimide (OBM-20) for the detection of metal ions in water through UV-Vis spectroscopy. Anionic sulphonated co-polyimide (OBM-20) was synthesized by a two-step thermal imidization reaction. Hydrophilic anionic sulphonate group possessing strong affinity towards heavy metal ions resulted in improved interaction of OBM-20 with metal ions in aqueous media. OBM-20 showed different absorptions in UV region upon interacting with Ni (II), Co (II), and Cr (III) ions in deionized water at room temperature and neutral pH. Interestingly, OBM-20 demonstrated that it can serve as an optical chemical sensor and metal ion receptor for nanomolar detection of toxic metal ions, particularly Ni (II), Co (II), and Cr (III) existing in aqueous media. Sulphonated co-polyimide resulted in efficient sensing of Ni (II) as compared to slightly larger metals such as Co (II) and Cr (III) in aqueous solution. Ultimately, the assessment of the sensing properties of OBM-20 revealed that it can function as a selective Ni (II) ions sensor.