Selective Colorimetric Detection Research Articles

Highly sensitive colorimetric and paper-based detection for sildenafil in functional food based on monodispersed spherical magnetic graphene composite nanozyme

BackgroundSildenafil (SIL) is regarded as an illegal adulterant in functional foods. Some functional foods doped with SIL have posed significant concern about their safety risks. However, the facile colorimetric detection of SIL is rarely investigated. ResultsHerein, we prepared a monodispersed spherical composite nanozyme (Fe3O4–NH2/GONRs), possessing excellent peroxidase-like (POD-like) and catalase-like (CAT-like) activities and strong superparamagnetic property. The enzyme-like activities of Fe3O4–NH2/GONRs can be selectively inhibited by SIL due to the synergistic effect of hydrogen bonds and π-π stacking between Fe3O4–NH2/GONRs and SIL. Leveraging this mechanism, a highly sensitive and selective colorimetric detection for SIL with a detection limit (LOD) of 0.26 ng/mL was developed. In addition, we prepared a three-dimensional paper-based analytical device (3D-PAD) for SIL colorimetric detection with naked-eyes and the semi-quantitative analysis with a LOD of 88 ng/mL. SignificanceThe proposed colorimetric and PAD detections demonstrated the advantages of low-cost, highly sensitive and selective, thus have promise application potential in the rapid detection of adulterated functional foods.

A coumarin containing hemicyanine-based probe for dual channel detection of cyanide ion

Cyanide(CN−) is known as one of the most toxic inorganic anions and is harmful to the environment and human health. Its wide use and severe toxicity have led to the development of highly selective cyanide detection, and quantification is desirable. A coumarin-containing hemicyanine-based probe has been developed for highly selective colorimetric and fluorometric detection of cyanide in acetonitrile and aqueous medium. The probe was characterized by 1D NMR (1H and 13C) and HRMS Spectroscopy, and the sensing properties have been studied in colorimetric and fluorometric methods. The high selectivity of the probe for CN− was established by UV–vis and fluorescence spectroscopy in the presence of other competing anions. The probe can detect cyanide as low as 0.7 μM within 90 s. A remarkable change in spectroscopic properties has been observed upon adding cyanide ion. The weakly luminescent probe emitted strongly upon the reaction with CN− which is due to the inhibition of internal charge transfer (ICT) from coumarin to indolinium moiety. Furthermore, the colour change from yellow to colourless and the appearance of a blue luminescence, which can be observed by the naked eye, provides a simple real-time method for cyanide detection, also supported by 1H NMR titration and theoretical study. Furthermore, a paper strip kit loaded with probe has been constructed for a real-time application of CN detection without any interference from other competitive analytes.

β-CD@AgNPs with peroxisase-like activity for colorimetric determination of chiral tryptophan

Different enantiomer forms of amino acids play different roles in multifarious fields, and improper use will cause irreversible effects. Therefore, the identification of chiral amino acids is a vital issue in the field of pharmaceutical analysis. Herein, a chiral sensing system of β-cyclodextrin coated silver nanoparticle (β-CD@AgNPs) with peroxidase-like activity was designed for the fast and efficient colorimetric identification of tryptophan (Trp) enantiomers based on the difference in binding capacity between D/L-Trp and β-CD. The results showed the satisfactory linearity for detecting D/L-Trp over the concentration range from 0.2 to 4 mM with a LOD of 0.16 and 0.18 mM, respectively. Moreover, the absorbance increased linearly with the rise of D-Trp concentration percentage in the Trp enantiomer mixture. The proposed method avoided the use of natural enzymes and improved the stability due to the protective effect of cyclodextrin, which provided a new idea for selective colorimetric recognition and detection of D/L-Trp based on cyclodextrin.

Ultrasensitive and selective colorimetric and smartphone-based detection of arsenic ions in aqueous solution using alliin-chitosan-AgNPs.

In this study, we developed a highly selective and sensitive colorimetric sensor for arsenic [As(iii)] detection using alliin-chitosan-stabilized silver nanoparticles (AC-AgNPs). The AC-AgNPs were synthesized using a complex prepared by mixing aqueous garlic extract containing alliin and chitosan extracted from shrimp. The synthesis of AC-AgNPs was confirmed by UV-vis spectroscopy, which showed a surface plasmon resonance (SPR) band at 403 nm, and TEM analysis revealing spherical nanoparticles with a mean diameter of 7.57 ± 3.52 nm. Upon the addition of As3+ ions, the brownish-coloured solution of AC-AgNPs became colourless. Moreover, the computational study revealed that among all the metal ions, only As3+ was able to form a stable complex with AC-AgNPs, with a binding energy of 8.7 kcal mol-1. The sensor exhibited a linear response to As(iii) concentrations ranging from 0.02 to 1.4 fM, with a detection limit of 0.023 fM. The highest activity was observed at pH 7 and temperature 25 °C. Interference studies demonstrated high selectivity against common metal ions. The study also demonstrated that the concentration of As3+ ions can be estimated by the decrease in red intensity and increase in green intensity in smartphone optical transduction signals. These results indicate the potential of the AC-AgNP-based sensor for reliable and efficient arsenic detection in environmental monitoring.

Sensitive and selective colorimetric sensor detection of Sn (II): An aqueous, paper, and gel-based method by green biomimetic silver nanoparticles

Tin contamination in waters due to mining and natural activities in high concentrations can threaten human health. This research presents the development of a sensitive and selective colorimetric sensor in aqueous, paper, and gel-based to detect Sn2+. The development of such sensors is promising, with attractive advantages such as intense color, fast naked-eye response, and simple continuous fabrication. The addition of Sn2+ ions will change the color of the medium because curcumin (Cur) interacts with Sn2+, causing a decrease in free Cur, silver nanoparticles (AgNPs) becoming less stable, and a change in particle size. Colorimetric changes in Sn2+ were achieved by visual inspection within 10 min for aqueous-based and 20 min for paper and gel-based. The good linear relationship (R2 = 0.9999) between Sn2+ and Δ absorption with a detection limit of up to 66.99 µg/L. This method is relatively scalable in determining Sn2+ and shows good recovery between 80 and 105 %. This colorimetric sensor gives good sensitivity to Sn2+ metal ions which is expected to become the basic technology for developing in-situ sensors to monitor Sn2+ levels in tin industrial waste.

Selective colorimetric detection of trace chromium (III) based on silver nanoparticles aggregation via a domino-like reaction

A simple method for measuring and tracking Cr3+, particularly in water, are crucial for environmental protection and avoiding serious health implications. Herein, we report the synthesis of mannose functionalized silver nanoparticles (Ag@mannose NPs) for naked eye detection of Cr3+ ions. The Cr3+-induced selective stimuli on the surface of Ag@mannose NPs promote aggregation, resulting in a colour change from yellow to purple, which can be assessed by absorption spectroscopy. Zeta potential investigation revealed that the surface charge of Ag@mannose NPs was altered in the presence of Cr3+, resulting in aggregation, as validated by dynamic light scattering and transmission electron microscopy. Cyclic voltammetry study shows that the NPs surface stabilized with mannose was oxidized in the presence of Cr3+, causing a domino-like effect that resulted in NPs aggregation and colour change. The interference study demonstrated the selectivity and sensitivity of Ag@mannose NPs to Cr3+ over other metal ions. Ag@mannose NPs can detect Cr3+ in a wide pH range of 3–9. The lowest Cr3+ concentration detected by the naked eye is 0.6 μM (39 μg/L), under the World Health Organization permissible limit of chromium (50 μg/L) in drinking water. Finally, the Ag@mannose NPs sensing ability was demonstrated by detecting Cr3+ in tap and sewage water with a good recovery percentage.

Green synthesized AgNPs as a probe for colorimetric detection of Hg (II) ions in aqueous medium and fluorescent imaging in liver cell lines and its antibacterial activity

The present research aimed at green synthesis of Ag nanoparticles (AgNPs) based colorimetric sensor using persimmon leaf extract (PLE) for selective detection of mercuric ion (Hg2+). Optimization of reaction conditions viz. pH, concentration of PLE, time was done and further AgNPs were characterized using UV, IR, FE-SEM, EDX, XRD and TEM analysis. The developed AgNPs were evaluated for the selective colorimetric detection of Hg2+ in aqueous medium and fluorescence imaging of Hg2+ ions in liver cell lines. Later, the antibacterial activity of AgNPs was performed against S. aureus and E. coli. The findings of the study revealed that PLE mediated AgNPs exhibited notable limit of detection up to 0.1 ppb, high efficiency, and stability. The antibacterial study indicated that developed AgNPs has impressive bacterial inhibiting properties against the tested bacterial strains. In conclusion, developed biogenic AgNPs has high selectivity and notable sensitivity towards Hg2+ ions and may be used as key tool water remediation.Graphical abstract

A "Pincer" Type of Acridine-Triazole Fluorescent Dye for Iodine Detection by Both 'Naked-Eye' Colorimetric and Fluorometric Modes.

Iodine, primarily in the form of iodide (I-), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions has been a significant challenge for decades due to interference from other anions. In this study, we designed and synthesized a new pincer-type acridine-triazole fluorescent probe (probe 1) with an acridine ring as a spacer and a triazole as a linking arm attached to two naphthol groups. This probe can selectively recognize iodide ions in a mixed solvent of THF/H2O (v/v, 9/1), changing its color from colorless to light yellow, making it suitable for highly sensitive and selective colorimetric and fluorescent detection in water systems. We also synthesized another molecular tweezer-type acridine-triazole fluorescent probe (probe 2) that exhibits uniform detection characteristics for iodide ions in the acetonitrile system. Interestingly, compared to probe 2, probe 1 can be detected by the naked eye due to its circulation effect, providing a simple method for iodine detection. The detection limit of probe 1 is determined to be 10-8 mol·L-1 by spectrometric titration and isothermal titration calorimetry measurements. The binding stoichiometry between probe 1 and iodide ions is calculated to be 1:1 by these methods, and the binding constant is 2 × 105 mol·L-1.

Selective Colorimetric Detection of Pb(II) Ions by Using Green Synthesized Gold Nanoparticles with Orange Peel Extract

Gold nanoparticles (AuNPs) were prepared by using a green approach that employed orange (citrus sinensis) peel water extract (OPE) as a reducing agent. In this case, the organic compounds present in orange peel were able to reduce Au(III) to Au(0) and, at the same time, to act as a capping agent, functionalizing the surface of the AuNPs, stabilizing them in a water solution. This “green” approach valorizes orange peel waste as a resourceful material and makes the synthetic process of AuNPs more environmentally sustainable, safe, and economically feasible than the traditional methods. The obtained gold nanoparticles (AuNPs@OPE) were characterized by FT–IR, DLS, SEM analysis, and UV–Vis spectroscopy; the latter showed a characteristic surface plasmon resonance (SPR) band at 530 nm, typical of spherical gold nanoparticles. The AuNPs@OPE were then tested as colorimetric sensors for heavy metals in water, showing an affinity and selectivity toward Pb2+. In fact, in the presence of Pb2+, the added cation favors the aggregation process, and, in this case, nanoparticles form clusters due to the interactions between Pb2+ and the carboxyl/hydroxyl groups on the surface of the AuNPs@OPE, increasing the size of the nanostructure. This process is accompanied by a change in color of the AuNPs@OPE from pink to violet, with a formation of a second, new SPR band, at a higher wavelength, relative to the aggregate formation. The colorimetric assay was tested at different times with the addition of Pb2+ ions showing different LOD values of 13.31 µM and 0.05 µM after 15 min and 90 min, respectively. The proposed colorimetric assay was also tested for analyzing Pb2+ in drinking water samples demonstrating the reliability to use AuNPs@OPE with real samples.

Sensing the invisible: Ultrasensitive and selective colorimetric detection of E. coli O157:H7 based on masking the peroxidase-mimetic activity of aptamer-modified Au/Fe3O4

Escherichia coli O157:H7 (E. coli O157:H7) emerges as a significantly worrisome pathogen associated with foodborne illnesses, emphasizing the imperative for creating precise detection tools. In this investigation, we developed a sensitive colorimetric biosensor for detecting E. coli O157:H7. It was constructed using a nanozyme comprised of Au@Fe3O4 NPs, which was fabricated and subsequently modified with an aptamer (Apt). The nanozyme harnesses its inherent peroxidase-like activity to facilitate the transformation of reduced TMB into its oxidized form in the presence of H2O2, resulting in a noticeable shift to a blue color. However, the presence of E. coli O157:H7 effectively diminished the absorbance of oxidized TMB. Consequently, the normalized absorbance at 652 nm demonstrates a linear decrease corresponding to concentrations of E. coli O157:H7 within the range of 101 to 108 CFU mL−1 with a low limit of detection (LOD, S/N = 3) of 3 CFU mL−1.

Ultra-rapid and highly selective colorimetric detection of hydrochloric acid via an aggregation to dispersion change of gold nanoparticles.

A rapid and highly selective naked-eye detection of hydrochloric acid (HCl) in an aqueous medium was established using HCl-triggered redispersion of gold nanoparticle aggregates.

Zn2+/GNPs nanocomposite for highly selective colorimetric detection of creatinine in urine samples of CKD patients

This research reports the fabrication of Zn2+/gold nanoparticles (GNPs) nanocomposite for colorimetric detection of creatinine (CR) in diverse media (e.g., water, artificial urine, and urine samples) between healthy subjects and chronic kidney disease (CKD) patients. The color of GNPs in suspension changed from characteristic wine-red (λabsorption = 545 ± 5 nm) to colorless or black upon the formation of nanocomposite with Zn2+ ions. However, upon addition of CR to Zn2+/GNPs nanocomposite suspension, the characteristic wine-red color of GNPs was restored. Our experimental analysis evidently validated the hypothesis on Zn2+ induced agglomeration of GNPs and their subsequent anti-agglomeration upon the addition of CR to the Zn2+/GNPs. Overall, our approach offered highly sensitive recognition of CR with a limit of detection of 2 µg·mL−1 (R2 = 0.95) along with excellent stability (>three months), selectivity (in the presence of interfering biochemicals (e.g., urea,ascorbic acid, and glucose, glutathione, Na+, K+, Ca2+, Mg2+, PO43−, and SO4 2−)), and reproducibility (relative standard deviation ∼ 9 %). Finally, the great potential of our method for CR recognition was also confirmed by good agreement (R2 = 0.95) with the gold standard ‘Jaffe’ method along with the Bland-Altman analysis for urine samples between health subjects (n = 15) and CKD patients (n = 11). In near future, a quantitative lateral flow biosensor is expected to be developed for non-invasive detection of CR through the integration of the proposed approach with the machine learning tools.

Dual amplification–based ultrasensitive and highly selective colorimetric detection of miRNA

In this study, we combined a Pradeep Kumar (PK)-probe with a ligation–transcription–ramified RCA (LTR) dual-amplification system for the isothermal colorimetric detection of miRNA 25-3P, where the PK-probe transformed from its pink color to colorless in the presence of the amplification byproduct pyrophosphate (PPi), thereby allowing the simple naked-eye qualitative detection of the miRNA. Through this double-amplification strategy, the limit of detection reached as low as 91.4 aM—quite extraordinary sensitivity for a colorimetric miRNA detection system based on absorbance readings. Our detection system also operated with high specificity, the result of using two different target-selective ligation steps (linear DNA ligation and circular DNA ligation) mediated by SplintR ligase, and so could discriminate single-mismatched from perfectly matched target sequences. We suspect that this ultrasensitive and selective PK-probe/LTR dual-amplification system should be a great colorimetric diagnostic for the detection of any miRNA with high efficiency.

Rhodamine hydrazide-linked naphthalimide derivative: Selective naked eye detection of Cu2+, S2− and understanding the therapeutic potential of the copper complex as an anti-cervical cancer agent

A naphthalimide-labeled rhodamine hydrazone derivative HL has been synthesized, characterized and examined in metal ion recognition. It shows selective colorimetric detection of Cu2+ over a number of other metal ions with a detection limit of 1.66 × 10−7 M in CH3CN/HEPES buffer (v/v = 2:1, pH = 6.8). The spirolactam ring of rhodamine and the imino-phenol motif of naphthalimide in HL are involved in complexation of Cu2+ as shown by single crystal X-ray. Single crystal of the copper-complex is prepared by utilizing NaSCN and it is characterized as CuL(SCN). The emergence of new absorption at 550 nm in UV–vis and the pink color of the solution reveal the selective interaction toward Cu2+. HL is characterized as a fluorescence resonance energy transfer (FRET) system that remains ‘turned OFF’ while spirolactam ring exists. In the presence of Cu2+, FRET is ‘turned ON’ via the opening of spirolactam ring to give emission at 580 nm which is less intense due to the quenching effect of Cu2+ ion. The complexation is reversible and the ensemble of Cu2+.HL selectively recognizes S2− over a series of different anions involving a color change from pink to colorless via the formation of spirolactam ring. The copper complex CuL(SCN) is further employed to understand its efficacy as a therapeutic agent. The complex is cytotoxic to high-risk HPV positive cervical cancer cell lines like SiHa and HeLa and is efficient in the generation and accumulation of reactive oxygen species (ROS). The complex also initiates nuclear blebbing and shows DNA degradation as understood by DNA laddering assay.

A porphyrin-based conjugated microporous polymer as a nanozyme for glucose colorimetric sensing

The development of peroxidase mimics with enhanced peroxidase-like activity is critical to building a convenient and fast glucose colorimetric sensor. Herein, a porphyrin-based conjugated microporous polymer (FePCMP) was synthesized through a Pd-/CuI catalyzed Sonogashira coupling reaction. The FePCMP exhibited specific and superior POD-like activity evaluated by the fast oxidation of 3,3[Formula: see text],5,5[Formula: see text]-tetramethylbenzidine (a chromogenic substrate, TMB) to form the blue product (oxTMB) in the presence of H2O2. The outstanding POD-like activity is mainly ascribed to the Fe-N4 active sites and the cross-linked porous framework of FePCMP. Furthermore, the FePCMP was applied in selective colorimetric detection of glucose through a glucose oxidase biocatalytic cascade reaction with a low detection limit (LOD) of 0.031 [Formula: see text]M in the linear range of 0.2–5 [Formula: see text]M. This study not only provided a new method for the design and synesis of specific POD-like nanozymes, but also the prepared FePCMP can be used as a POD-like enzyme for the colorimetric detection of other molecules, such as cholesterol, acetylcholine, etc.

A Novel Naphthylidene-diimine Chemosensor for Selective Colorimetric and Fluorometric Detection of Al3+ and CN- Ions.

A naphthylidene-diimine L2 was newly designed, and its structure was identified by elemental analysis and spectroscopic methods. The effect of temperature, acid-base and light on enol-keto tautomerism in this Schiff base was evaluated by colorimetry, UV-Vis and fluorescence spectroscopy. Under irradiation 365 nm, L2 emitted yellow, orange and strong green emission in pure, basic and aqueous DMSO media (v/v, 1/1), respectively. Its ionochromic behavior against various cations (Fe3+, Al3+, Cr3+, Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, Ba2+ and Ag+) and anions (F-, Cl-, CH3COO-, SO32-, S2O32-, HSO4-, H2PO4-, NO3-, CN-, and OH-) was investigated in aqueous DMSO media (v/v, 1/1) by UV-Vis and fluorescence experiments. Dark yellow color of L2 changed to colorless for Fe3+, Cr3+ and HSO4- ions, and turned to light yellow for Al3+ and Cu2+ ions, and to orange for CN- and OH- ions. According to UV-Vis data, the chemosensor displayed selective recognition towards Fe3+, Al3+, Cu2+, HSO4-, CN- and OH- with a 1:1 stoichiometric ratio. At the excitation wavelength of 365 nm, L2 gave strong yellowish white emission (λem = 445 and 539 nm) in the presence of Al3+, and the intensity increased about 12.5 times. On the other hand, the chemosensor displayed one emission band at 452 nm and 450 nm in the presence of CN- and OH- with 1.9 fold and 2.3 fold fluorescence enhancement, respectively.

An ultrasensitive colorimetric biosensor for the detection of Gram-positive bacteria by integrating paper-based enrichment and carbon dot-based selective recognition

Rapid screening of bacteria by low-cost and eco-friendly material-based approaches is still a major challenge. Herein, a colorimetric biosensor was designed for the ultrasensitive and rapid detection of Gram-positive bacteria. The biosensor exploited polydopamine and polyethyleneimine (PDA-PEI)-modified papers for separating bacteria and carbon dots (CDs) for selective colorimetric detection of Gram-positive bacteria. Noble metal-free CDs can target Gram-positive bacteria by binding with peptidoglycan and possess peroxidase-like activity. Thus, they can avert the step of modifying recognition probes, facilitating biosensor fabrication, and reducing the cost. This biosensor can detect S. aureus as low as 1 cfu mL−1, L. monocytogenes as low as 5 cfu mL−1, and B. subtilis as low as 9 cfu mL−1 within 55 min. In addition, a portable device was constructed to enable convenient and on-site quantitative detection of Gram-positive bacteria. The feasibility of the biosensor was verified by detecting Gram-positive bacteria in eggshell and sausage samples with recoveries ranging from 91.2% to 110%.

A Zn-coordination polymer for the quantitative and selective colorimetric detection of residual tetracycline in aqueous solution and urine.

A one-step solvothermal synthesis provides a functional crystalline one-dimensional Zn-coordination polymer (Zn-CP) with excellent stability in aqueous solution over a wide range of temperature and pH. Zn-CP is a rapid, highly sensitive and selective sensor for detecting tetracycline (TC). Quantitative TC detection is based on the ratio of fluorescence intensities I530/I420, with a limit of detection (LOD) of 5.51nM in aqueous solution and 47.17nM in human urine. The characteristics of colorimetric TC sensing by Zn-CP are highly favorable for application because the color of Zn-CP changes in the visible part of the spectrum from blue-purple to yellow-green upon addition of TC. Conversion of these colors into an RGB signal is simply achieved with an app for the smart phone and provides LODs of 8.04nM and 0.13μM TC in water and urine, respectively. Our suggested sensing mechanisms assume that the fluorescence intensity of Zn-CP@TC at 530nm is enhanced by energy transfer of Zn-CP to TC, while the fluorescence of Zn-CP at 420nm is quenched by photoinduced electron transfer (PET) from TC to the organic ligand in Zn-CP. These fluorescence properties make Zn-CP a convenient, low-cost, rapid and green detection device for monitoring TC under physiological conditions and in aqueous media.

Peroxidase Mimic Sulfur‐Rich CuO‐Carbon Nitride Core‐Shell Nanorods for the Colorimetric Detection of Aminophenol Isomers

AbstractA solid‐state method was used to derive a sulfur rich CuO‐carbon nitride core‐shell nano‐composite from a Cu‐organic hybrid. The synthesized material was characterized by XRD, morphology by SEM and TEM. Elemental analysis was investigated using EDS. The novel sulfur rich CuO‐carbon nitride core‐shell composite demonstrated as peroxidase activity for the oxidation of aminophenol isomers in the presence of H2O2. The oxidized products of o‐aminophenol (o‐AP) and p‐aminophenol (p‐AP) in phosphate buffer (PB, pH 7) showed strong absorption peaks at 435 and 475 nm, respectively in the UV‐Visible spectra. Whereas no oxidation reaction was observed for m‐aminophenol. Kinetic analysis of sulfur rich CuO‐graphitic carbon nitride revealed that the catalyst functioned by a ping‐pong mechanism for the oxidation of both o‐AP & p‐AP by hydrogen peroxide (H2O2). Based on KM values, substrate affinities were in the order o‐AP>H2O2>p‐AP. We further used this material for selective colorimetric detection of o‐AP and p‐AP in PB pH 7. The linear ranges obtained for o‐AP and p‐AP were 1–200 μM (LOD=1.5 μM, r2=0.99) and 10–500 μM (LOD=2.27 μM, r2=0.99), respectively. The developed analytical platform was used to detect these isomers in river water and p‐AP in artificial urine.

Pyrene derived imine functionalized moiety for highly selective colorimetric detection of Cu2+ ion real time sample with supportive DFT studies

Schiff base probe 4-hydroxy-N-(pyrene -1-yl-methylene) benzo hydrazide (PyrBH) has been synthesized and rationally designed as a rapid and highly selective colorimetric sensor for Cu2+ ions in the semi-aqueous medium. Structural characterization of PyrBH was confirmed by NMR, FT-IR, and HRMS spectral techniques. The cation binding affinity with the PyrBH probe was confirmed colorimetric study using the UV-Visible spectral method. The probe PyrBH exhibits a colorimetric response from colourless to yellow solutions containing Cu2+ ions. UV-Visible studies confirmed the formation of a 1:1 stoichiometry complex with a calculated binding constant Ka value (3.464 × 10-5 M) of suggests stable complex formation between the Cu2+ ions and the sensing PyrBH probe. The limit of detection (LOD) was found to be 2.19 × 10-7 M. The fabrication of test paper strips with the probe was done to detect the presence of Cu2+ ions in the real sample. The DFT & TD-DFT computational analysis was used to determine the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels, which it associates with satisfactory correlation.