Detection Of Cyanide Research Articles

A new naphthopyran-based chemodosimeter with aggregation-induced emission: Selective dual-channel detection of cyanide ion in aqueous medium and test strips

A novel green emissive AIE active probe, a naphthopyran-malononitrile conjugate (NPM), was utilized for selective dual channel (colorimetric and fluorimetric) sensing of CN− ions in DMSO-water (2/3, v/v, pH = 7.4) solution. The nucleophilic addition of CN− ion on the dicyano-vinyl group breaks the π-electron conjugation, thereby restricting intra-molecular charge transfer(ICT) process in the probe NPM and leading to a visual color change and observable spectral changes. NPM shows good selectivity for CN− ions with the LOD of 4.27 × 10−7 M, which renders it a candidate probe for cyanide detection in aqueous environments. For the practical applicability, NPM-coated paper strips were prepared for convenient, on-site detection of cyanide in aqueous medium.

A novel colorimetric and fluorometric probe for the detection of CN− with high selectivity in aqueous media

A novel colorimetric and fluorometric probe L1 for detecting CN− with high selectivity was constructed and synthesized based on intramolecular charge transfer (ICT). Remarkably, L1 was found to be exclusively responsive to CN− via nucleophilic attack of dicyanovinyl group via 1H NMR titration experiment. The detection system exhibited “turn-on” fluorescence with the addition of cyanide, which was opposite to previously reported fluorescence quenching probes with the same sensing process. Moreover, the detection limit of L1 for CN− was determined to be 1.1 μM, lower than the standard (1.9 μM) regulated by the World Health Organization (WHO). This work demonstrated that L1 could serve as both a colorimetric and a fluorimetric sensor for cyanide detection in pure water, making it possible for the applications of cyanide detection in water.

Ruthenium-based phosphorescent probe for selective and naked-eye detection of cyanide in aqueous media

A simple molecular phosphorescent Ru(II) probe P1 has been synthesized by the reaction of 5-aldehyde-2,2′-bipyridine with ruthenium(II) chlorides under mild conditions. The probe upon interaction with different cation and anion showed high selectivity and sensitivity for cyanide ion (CN‒) through phosphorescence “turn-on” response in aqueous solution (60% water) with a detection limit of 0.75 μM. The significant phosphorescence enhancement (~ 30-fold) is attributed to the nucleophilic addition of cyanide ion to the aldehyde groups of the ruthenium complex in 3 : 1 stoichiometry, in which a naked-eye sensitive orange red color of solution changed to a yellow. The generation of cyanohydrin species through nucleophilic addition has been confirmed by 1H NMR, FT-IR and mass spectra. Based on the color change of the solution, a visual colorimetric strip was prepared, which also showed good detection performance on cyanide ion with quick response time. The prominent efficiency of the Ru(II) probe proved the potential possibility of application in biosystems relating with cyanide ion.

Highly Stable Upconverting Nanocrystal-Polydiacetylenes Nanoplates for Orthogonal Dual Signaling-Based Detection of Cyanide.

Although the unique optical signaling properties of polydiacetylene (PDA) have been exploited in diverse bio-chemosensors, the practical application of most PDA sensor systems is limited by their instability in harsh environments and fluorescence signal weakness. Herein, a universal design principle for a highly stable PDA sensor system with a practical dual signaling capability is developed to detect cyanide (CN) ions, which are commonly found in drinking water. Effective metal intercalation and enhanced hydrophobic intermolecular interactions between PDA-metal supramolecules are used to construct highly stacked PDA-metal nanoplates that feature unusual optical stability upon exposure to strong acids, bases, organic solvents, and thermal/mechanical stresses, and can selectively detect CN anions, concomitantly undergoing a specific supramolecular structure change. To realize the practical dual signaling capability of the PDA sensor system, upconverting nanocrystals (UCNs) are incorporated into highly stacked PDA-metal nanoplates, and practical dual signaling (orthogonal changes in luminescence and visible color) is demonstrated using a portable detection system. The presented universal design principle is expected to be suitable for the development of other highly stable and selective PDA sensor systems with practical dual signaling capability.

Pyridine-hydrazone-controlled cyanide detection in aqueous media and solid-state: tuning the excited-state intramolecular proton transfer (ESIPT) fluorescence modulated by intramolecular NHBr hydrogen bonding.

A new efficient pyridine-hydrazone-substituted naphthalimide receptor 4a-E has been synthesized as a selective colorimetric and fluorescent chemosensor for cyanide sensing in aqueous environments through a unique excited-state intramolecular proton transfer (ESIPT) mechanism. The addition of a Br group to the fluorophore skeleton at the ortho-position of hydrazone generates reference compounds (4b-E and 4c-Z). Interestingly, the potential intramolecular NHBr hydrogen bonding might compete with the anion-induced intermolecular NHA- hydrogen bonding, resulting in dramatic ESIPT suppression. The high emission of probe 4a-E and other control probes in solid-state is also investigated. Moreover, probe 4a-E preloaded on test papers, upon cyanide treatment, shows obvious changes in color which demonstrates that 4a-E is a writable platform. More importantly, it exhibits great potential application for the detection of cyanide in food materials and excellent performance in real-world water samples.

AIE-active polysulfatesviaa sulfur(vi) fluoride exchange (SuFEx) click reaction and investigation of their two-photon fluorescence and cyanide detection in water and in living cells

Three polysulfates P1, P2 and P3 containing two representative AIE-active groups, tetraphenyl ethylene and naphthylamide, were successfully synthesized based on a sulfur(vi) fluoride exchange (SuFEx) click reaction.

Catalyst + chemodosimeter → chemosensor: incorporation of catalytic functionality in an indicator displacement assay to realize reversible chemosensing detection

A new bimetallic complex, (CN)3FeII(tppz)CuIICl (tppz = 2,3,5,6-tetra(2′-pyridyl)pyrazine), was synthesized to demonstrate the concept of indicator/catalyst displacement assay for the simultaneous detection and detoxification of cyanide.

A new chromogenic and fluorescent chemosensor based on a naphthol-bisthiazolopyridine hybrid: a fast response and selective detection of multiple targets, silver, cyanide, sulfide, and hydrogen sulfide ions and gaseous H2S.

A novel chemosensor 1 based on a naphthol-bisthiazolopyridine hybrid was synthesized and characterized. Among the various screened cations and anions, chemosensor 1 selectively recognized Ag+ and CN- ions by relying on the color change and distinct absorption and emission changes. Moreover, the probe 1·Ag+ was well operable for the selective monitoring of S2-, HS- and H2S as evidenced by the different color and optical changes. The selective detection of all the anions was simply based on the breakage of the intramolecular hydrogen bonding of 1, followed by the protonation or deprotonation mechanism. In general, chemosensor 1 is a promising indicator in terms of its ease-of-use, selectivity, sensitivity, and rapid response (<1 s). Moreover, the visual detection and concentration determination of these analytes by solution or solid kits are the advantages for the practical applications of this sensor.

A new chemosensor for cyanide in blood based on the Pd complex of 2-(5-bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol.

A new indirect chemosensor for the detection of cyanide in blood is developed. 2-(5-Bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol, a yellow dye, forms a blue-coloured complex with palladium ions. The yellow colour of this complex is regained upon reaction with cyanide ions. The complex shows high selectivity for the detection of cyanide over 16 other anions. The system was applied to two different methods for the detection of cyanide in human whole blood. As a quantitative absorbance method, blood samples were mixed with acid, and the resulting vaporised hydrogen cyanide was absorbed in an alkaline solution containing the complex in a Conway cell. The resulting absorbance response of the solution at 450 nm is linear over the range 4-40 μM (R2 = 1.000), and the limit of detection is 0.6 μM. Furthermore, the complex-soaked paper is applicable as a test strip for cyanide detection. When a test strip is used with 0.5 mL of blood, the limit of detection is 15 μM. The detection limits of these two methods are below the toxic blood cyanide concentration (19 μM). Therefore, both methods allow the quantification and screening of cyanide in blood samples. Furthermore, the test strip is low cost and enables on-site analysis.

A new salamo-based colorimetric and fluorescent turn-on sensor with aggregation-induced emission for the rapid and highly sensitive detection of cyanide in real samples

A new, simple, and easy-to-manufacture highly selective and sensitive dual-mode sensorA1with the aggregation-induced emission properties is used for CN−colorimetric and fluorescence detection.

A highly sensitive and selective fluorescent turn-on chemosensor bearing a 7-diethylaminocoumarin moiety for the detection of cyanide in organic and aqueous solutions

Novel 7-diethylaminocoumarin based dyes showed high sensitivity and selectivity to cyanide anions in both organic and aqueous solutions, which was observed by a drastic increment in the emission intensity.

Azobenzene–Hemicyanine Conjugated Polymeric Chemosensor for the Rapid and Selective Detection of Cyanide in Pure Aqueous Media

A water-soluble polymeric probe was designed and synthesized that can be used for the colorimetric selective detection of cyanide ions in pure aqueous media. In particular, P1, a water-soluble random terpolymer (P1) of N,N′-dimethylacrylamide, 2-((E)-4-((E)-(4-((2-(acryloyloxy)ethyl)(methyl)amino)phenyl)diazenyl)styryl)-1,3,3-trimethyl-3H-indol-1-ium (M1), and N-(4-benzoylphenyl)acrylamide was synthesized via traditional free-radical polymerization. Upon the addition of CN− ions to a P1 solution, a macroscopically detectable color change of the solution from brick red to light yellow took place, which was associated with a low limit of analyte detection (1.23 μM). Notably, P1 exhibited excellent selectivity toward CN− over other anions and biothiols, which may be present in the medium. Such highly selective colorimetric response to CN− by P1 originated from the nucleophilic attack of CN− anions onto the electron-deficient polarized CN bonds of P1's indolium moieties, resulting in the perturbation of the intramolecular charge transfer process occurring within the probe via destruction of the polymer's extended π-conjugation. P1 was also immobilized on a quartz slide by spin coating and then exposed to ultraviolet light. The resulting polymeric film displayed a rapid response to CN− consisting in a distinct color change, extending the scope of the usefulness of P1 as a cyanide-ion probe beyond the solution phase. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 124–131

Highly sensitive turn-off fluorescent detection of cyanide in aqueous medium using dicyanovinyl-substituted phenanthridine fluorophore.

Herein, the turn-off fluorescence sensor of 2-((4′-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)-[1,1′-biphenyl]-4-yl)methylene)malanonitrile (7) was developed for the recognition of CN− ions and studied using different spectroscopic techniques. The selective recognition of CN− ions by 7 was investigated via UV-vis spectroscopy and fluorescence studies in acetonitrile solvent, which exhibited an obvious color change from orange to colorless under 365 UV light. The sensor compound 7 possesses a high binding constant (Ka) for CN− ions in the order of 5.22 × 106 M−1. The results from the interference studies revealed that probe 7 shows high sensing selectivity and sensitivity for CN− ions over other competitive anions. Probe 7 interacts with cyanide to form a 1 : 1 adduct, and this mechanism was further verified by 1H NMR titration, Job's plot analyses and DFT studies. The sensor probe 7 exhibits advantages such as low limit of detection (LOD) of 39.3 nM, fast response and sensing in a wide pH range of 3 to 11. The practical application of 7 was successfully demonstrated for the determination of CN− ions in test paper strips and various water samples.

Correction: A colorimetric probe for the real-time naked eye detection of cyanide and hydroxide ions in tap water: experimental and theoretical studies.

Correction for 'A colorimetric probe for the real-time naked eye detection of cyanide and hydroxide ions in tap water: experimental and theoretical studies' by Veikko Uahengo et al., Analyst, 2019, 144, 6422-6431.

Post-synthetic modification of a metal-organic framework with a chemodosimeter for the rapid detection of lethal cyanide via dual emission.

A new Hf(iv) based metal-organic framework with the UiO-66 (UiO = University of Oslo) topology was prepared via a standard modulated solvothermal reaction. The weakly emissive MOF material was well characterized via various analytical techniques. The parent MOF was then post-synthetically modified with a highly emissive pyrene based chemodosimeter probe without altering the parent framework structure. The incorporation of the chemodosimeter in the modified MOF material was successfully confirmed by using FT-IR and 1H NMR spectroscopy. The emission behaviour of the parent MOF was changed drastically with a noticeable colour change after post-synthetic modification. After modification, the MOF material showed a very selective colorimetric and fluorometric dual-emissive response towards lethal cyanide ions. A large blue shift (Δλ = 127 nm) was observed in the emission spectra which can be also visualized with the naked eye under a hand held UV lamp. The presence of a vinyl functional group in the chemodosimeter can serve as a potential nucleophilic reaction centre, which was also confirmed by the DFT calculations. The reaction based sensing mechanism of the MOF material was successfully confirmed by 1H NMR spectroscopy. Furthermore, to apply the modified MOF material in real life, the test strip based sensing of cyanide in drinking water was demonstrated.

A simple fluorophore-imine ensemble for colorimetric and fluorescent detection of CN- and HS- in aqueous solution.

Colorimetric and fluorescent detection of cyanide and hydrogen sulfide ions has been effected using a simple organic probe in H2O:DMSO (20:80, v/v) medium. The probe exhibits a colour change from pale-yellow to red upon addition of these analytes under normal light and fluorescent change from green to red under UV lamp. Other competitive ions show no observable colour or fluorescence change. The binding constants of cyanide and hydrogen sulfide ions with the probe determined using fluorescence titration data are found to be 2.1×104 and 1.6×104 M-1, respectively. The probe fluorimetrically detects the analytes in a wide pH range (4-10). 1H and 13C NMR studies suggest that the probe senses cyanide ion through deprotonation and nucleophilic addition mechanism and hydrogen sulfide ion via deprotonation mechanism. Detection limits of cyanide and hydrogen sulfide are determined to be 0.15 and 1μM, respectively. The practical utility of the probe has been demonstrated by same dual mode detection of cyanide in food materials like bitter almond, cassava flour and sprouting potato.

Optical detection of cyanide by palladium(II)-dithiazolopyridine probe at the parts per billion level

The ensemble of 2,6-bis(2-chlorophenyl)dithiazolo[4,5-b:5',4'-e]pyridine 1 with Pd2+ ions (1•Pd2+) was prepared for the detection of cyanide ions (CN¯) in 50% aqueous methanol. Among the tested metal ions, only Pd2+ sensitively induced the red shift of the absorption bands and the complete decrease of fluorescence emission. The detection limit toward Pd2+ was 2 ppb. The ensemble 1•Pd2+ selectively and rapidly detected a low concentration of cyanide ions by a colorimetric change (40 ppb) as well as a “turn-on” fluorescent response (5 ppb). Job’s plot revealed the complex formation with 1:1 stoichiometry. The binding and replacement mode of 1•Pd2+ and CN¯ were also confirmed by 1H NMR titrations and IR analysis. In general, a fast and selective recognition of CN¯ is reported.

Water-soluble fluorescent probe for simultaneous detection of cyanide, hypochlorite and bisulfite at different emission wavelengths

A fluorescent probe that responds at distinct wavelengths upon exposure to cyanide, hypochlorite, and bisulfite was synthesized. As a result, an easy to apply analytical methodology was developed for the detection of these ions. The feasibility of this method was evaluated by theoretical calculations. The probe exhibited excellent solubility in the test solution (H2O: DMF = 99: 1, v: v) with low detection limits for cyanide, hypochlorite and bisulfite (4.5 × 10 −8 M, 4.9 × 10 −7 M and 4.3 × 10 −8 M respectively) showing distinct emission wavelengths for each ion without interference in practical application. Furthermore, the probe had low toxicity and was applied for the imaging experiments of cyanide, hypochlorite and bisulfite in living HeLa and MDCK cells.

Detecting illegal cyanide fishing: Establishing the evidence base for a reliable, post-collection test

Ornamental fish have been legally harvested since the 1930's but in the 60's, cyanide fishing was first documented. Target fish exposed to the chemical are temporarily paralysed making them easier to catch, but with high post-capture mortality and significant ecological impacts, its use is banned in most exporting countries. To differentiate illegally caught fish from those sustainably collected, efforts to develop a post-collection detection test began nearly 30 years ago. However, even the most promising approach has been questioned by other researchers as unrepeatable under different experimental conditions. In this paper we summarise the evidence-base for establishing a cyanide detection test for live fish by evaluating current approaches. We describe the key knowledge gaps which continue to limit our progress in implementing a screening programme and highlight some alternative solutions which may provide greater short to medium term opportunities to prevent the illegal practise before fish enter the supply chain.

A self-assembled supramolecular gel constructed by phenazine derivative and its application in ultrasensitive detection of cyanide

In this work, we constructed a supramolecular gel (PN-G) by phenazine derivative, which can ultrasensitive detect cyanide (detection limit equals to 4.18 × 10−10 M). The decrease of fluorescent intensity displayed a linear relationship in the range of 0–0.4 equivalents of cyanide. And no significant fluorescence quenching was observed for all used interfering ions. The cyanide recognition mechanism of PN-G was verified by XRD, NMR, MS and SEM. With addition of cyanide to the supramolecular gel (PN-G), cyanide broken π-π stacking of PN-G, and then PN-G undergoes a nucleophilic addition reaction with CN−, resulting in fluorescence quenched.