Presence Of CN Research Articles

Benzothiazole-quinoline based probe for simultaneous colorimetric detection of CN- and Cu2+ ions, with fluorescence sensing for Cu2+: Mechanistic insights and practical applications in environmental monitoring and cellular analysis

The development and synthesis of notably targeted and colorimetric sensor based on an azomethine compound for the distinct recognition of Cu2+ and CN− ion individually in an aqueous dimethyl formamide solution is performed. In the presence of CN− and Cu2+, the sensor BTZ showed impressive colorimetric changes, going from pale yellow to orange and pale yellow to dark yellow, respectively. In the meantime, FL spectrum (Cu2+) and UV–vis spectroscopy (CN−/Cu2+) were used to assess the sensing features. The plausible binding mechanisms of CN− and Cu2+ ions with sensor BTZ have been studied using the 1H NMR titration, Job's plot and DFT technique. The bathochromic shift produced by the intramolecular charge transfer (ICT) transition may have been the source of the phenomenon. Furthermore, CN− ion in the commercial substance is quickly identified and measured with the naked eye by using sensor BTZ. It was found that the BTZ's LOD for CN− and Cu2+ was 0.280 × 10−7 M and 1.153 × 10−7 M, respectively. Moreover, 1:1 binding ratio for the reaction of CN− and Cu2+ ions with sensor BTZ were demonstrated by Job's plot, which was dependent on analytical data. The findings show that BTZ is an easy-to-use and practical probe for concurrently sensing cyanide and copper ions in environmental samples and living cells that have less cytotoxicity.

Optical emission characterization of an atmospheric pressure dielectric barrier discharge in nitrogen: Evolution of CN emissions during PTFE etching

AbstractThe present work investigates the etching of coated polytetrafluoroethylene (PTFE) films using an atmospheric pressure dielectric barrier discharge operating in nitrogen in a filamentary regime. For different treatment durations, the optical emission spectra were recorded over time. Most of the emissions are attributed to the N2 second positive system. The presence of CN is also observed, and its emissions rise with the exposure time of PTFE. This rise is attributed to the density of CN produced. The X‐ray photoelectron spectroscopy surface characterization suggests two etching regimes. This is linked with a change in slope in the intensity evolution of the optical emissions of the CN. At longer times, a fluorinated deposit on the electrode is observed, confirming a different nature of the etched material.

Improving the Properties of Gelatin-Based Films by Incorporation of "Pitanga" Leaf Extract and Crystalline Nanocellulose.

Biopolymer-based films can be activated by the incorporation of active compounds into their matrix. Plant extracts are rich in phenolic compounds, which have antimicrobial and/or antioxidant properties. The aim of this study was to produce gelatin-based active films and nanocomposite films incorporated with "pitanga" (Eugenia uniflora L.) leaf extract (PLE) and/or crystalline nanocellulose extracted from soybean straw (CN), and to study the physicochemical, functional, microstructural, thermal, UV/Vis light barrier, and antioxidant properties of these materials. PLE enhanced some film properties, such as tensile strength (from 30.2 MPa to 40.6 MPa), elastic modulus (from 9.3 MPa to 11.3 MPa), the UV/Vis light barrier, and antioxidant activity, in addition to affecting the microstructural, surface, and color properties. These improvements were even more significant in nanocomposites simultaneously containing PLE and CN (59.5 MPa for tensile strength and 15.1 MPa for elastic modulus), and these composites also had lower moisture content (12.2% compared to 13.5-14.4% for other treatments) and solubility in water (from 48.9% to 44.1%). These improvements may be the result of interactions that occur between PLE's polyphenols and gelatin, mainly in the presence of CN, probably due to the formation of a stable PLE-CN-gelatin complex. These results are relevant for the food packaging sector, as the activated nanocomposite films exhibited enhanced active, barrier, and mechanical properties due to the presence of PLE and CN, in addition to being entirely produced with sustainable components from natural and renewable sources.

Anticounterfeiting Feature of a Writable and Self-Erasable Ni(II)-Metallogel Pad via Fluorescent "Turn-On" Detection of Cyanide.

A Schiff base 5-(2-hydroxy-3-methoxybenzylidieneamino)-1-H-imidazole-4-carboxamide (HL) comprising multibinding sites has been synthesized with the aim of fabricating a supramolecular gel. The gelator HL was characterized by FT-IR, 1H & 13C NMR, and ESI-MS techniques and also formed a [Ni(L)2] complex. The gelation property of HL was investigated with various metal ions, wherein Ni(II) selectively forms a mechanically and thermally stable supramolecular metallogel (MG) in the presence of a triethylamine base in DMF-MeOH media. Characterization of MG was accomplished with different spectro-analytical techniques such as FT-IR, ESI-MS, powder-XRD, SEM, rheological investigations, UV/vis, and fluorescence. The gelator HL displays moderate emission upon addition of Ni2+ and gives "turn-off" fluorescence output by forming the complex [Ni(L)2] (MG) due to the chelation-enhanced quenching of fluorescence (CHEQ). Job plot and ESI-MS data suggested a 2:1 stoichiometry between HL and Ni(II) in MG. Further, MG exhibited highly selective and ultrasensitive "turn-on" fluorescence signaling with CN- in the background presence of several cations and anions. The limit of detection (LoD) of MG was determined to be 6.9 × 10-9 M for CN- using the fluorescence technique. Notably, MG behaves as a fluorescent writable pad material explicitly with CN- under 365 nm UV light but not under ordinary light and the fluorescent text is self-erased after 15 min. Hence, MG can be used as a metallogel pad in the presence of CN- to communicate secret messages. Overall, the present work explores the fabrication of a thermo- and mechanostable Ni(II)-metallogel (MG), which selectively and ultrasensitively detects CN- both in the solution phase and in the gel form, wherein MG behaves as a writable and self-erasable pad with anticounterfeiting features for practical applications.

A dual-mode fluorometric and smartphone-based colorimetric sensor for cyanide detection using tungsten disulfide quantum dots and silver nanoparticles

In this study, tungsten disulfide quantum dots (WS2 QDs) and silver nanoparticles (AgNPs) were applied to establish a dual-mode fluorometric and smartphone-based colorimetric sensor for the determination of cyanide ions (CN⁻). We indicated that the fluorescence intensity of WS2 QDs was quenched by AgNPs as a result of the inner filter effect (IFE) mechanism. Moreover, the quenched fluorescence intensity of WS2 QDs switched on again in the presence of CN⁻ due to the interaction between AgNPs and CN⁻, leading to destroy AgNPs, diminishing their yellow color and reducing their IFE on WS2 QDs. Based on these facts, we established a turn-off-on fluorometric (with a range of 0.5–30 and detection limits of 0.17 µM) and smartphone-based colorimetric sensor (with 5–500 µM and detection limits of 1.2 µM) for CN⁻ measurement. The sensor was exploited for CN⁻ analysis in water and food samples with satisfactory results. The established dual sensor benefits from both methods advantages such as the high sensitivity of fluorometric sensors as well as simple and visual detection of smartphone-based colorimetric sensors. Additionally, our developed smartphone-based colorimetric sensor can be used as a portable sensor for the sensitive, rapid and low-cost analysis of CN⁻ in the field.

Precisely designed NIR based conjugated framework as a solid state emitter for selective recognition of cyanide ion in solid state and cancer cells

Cyanide is undoubtedly dangerous and fast acting chemical employed in various industrial applications with toxic side effects, which raises urgent need for its monitoring. In this context, oxazolonaphthoimidazo[1,2-a]pyridine-malononitrile (ONIM) conjugate linked by vinyl linkage was designed, synthesized and characterised by FT-IR, NMR and mass spectrometry. The developed probe has been evaluated for the colorimetric and fluorometric detection of cyanide ion. An obvious color change with unique rapid “turn-off” fluorometric response was observed within 5 s upon addition of CN– thus reflecting its better acuteness and sensitivity over other competing anions. The developed probe exhibits a detection limit of 9.54 nM which is very low in comparison to maximum permitable amount of cyanide in drinking water (1.9 µM). The probe is stable within the pH range of 2–9 and suitable for the recognition of CN– in the pH range of 7 to 10, specially at neutral pH conditions. The chemodosimetric approach based detection mechanism was authenticated by 1H NMR titration and DFT calculations. The solid state applications were established by utilising ONIM impregnated TLC plates and filter paper in cyanide recognition. The solid state emissive behaviour of ONIM offers on-spot detection of the cyanide anion. Additionally, the practicability of ONIM has been extended in live cell imaging of CN– in human breast cancer cell (MDA-MB-231), which revealed a “turn-off” fluorescence response for the probe in the presence of CN– ion.

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.

Solar light driven enhanced photocatalytic treatment of azo dye contaminated water based on Co-doped ZnO/ g-C3N4 nanocomposite

The current research concentrated on the Co-precipitation synthesis of g-C3N4 (CN), ZnO, ZnO/CN, and Co-doped ZnO/CN nanocomposite, as well as the solar light enhanced photocatalytic treatment of Reactive Red 120 (RR120) from genuine wool textile effluent. The 3D flower-like structure of Co-doped ZnO distributed on the surface of CN thin sheets, according to structural studies employing XRD and SEM examinations Electrochemical experiments exhibited that the Co-doped ZnO/CN nanocomposite has a large electroactive surface area. The optical band-gap values of CN, ZnO, ZnO/CN, and Co-doped ZnO/CN nanocomposites were 2.68, 3.13, 2.38, and 2.23 eV, respectively, according to optical characterizations. The synergistic effects and heterojunction produced by Co-doped ZnO and CN can be linked to the narrow gap in nanocomposites. After 75, 60, 50, and 40 min of exposure to solar light, photocatalytic degradation assays for 250 mL of 20 mg/L RR120 solution in the presence of CN, ZnO, ZnO/CN, and Co-doped ZnO/CN nanocomposites demonstrated 100% dye treatment. The applicability of photocatalysts for decolorization of 250 mL of 10 mg/L RR120 prepared from actual wool textile wastewater was investigated, and the results showed that Co-doped ZnO/CN nanocomposites for treatment of RR120 from actual wool textile wastewater were highly efficient at photocatalytic degradation.

Uncovering solvent-engineering mechanisms in Y6:PM6 solar cells

Additives, like 1-chloronaphtalene (CN), are commonly used in Y6:PM6 solar cells as they lead to an increased power conversion efficiency. In this work, we investigate the influence of CN during spin coating of Y6:PM6 dissolved in chloroform via an in situ transmission setup. We show that, in the presence of CN, the film formation of Y6:PM6 can be divided into two parts: one related to the evaporation of chloroform and one related to the evaporation of CN. This is mostly related to Y6 being dissolved in CN. We find that even for low CN concentration, the film formation is not completed for several minutes after the spin coating process. Furthermore, the removal of CN is needed to achieve a smooth film surface. We demonstrate that this fast removal can be achieved by spin coating the electron transport layer PDINN from methanol. The methanol is acting as an anti-solvent for the CN, leading to its removal from the film. Using this approach, solar cells fabricated with a high CN concentration of 5% feature a comparable performance to ones with more common concentrations between 0.5% and 1%.

A reversible and selective chromogenic thiazole tagged chemosensor for Hg2+in aqueous medium: Crystal structure, theoretical investigations and real sample analysis

A novel thiazole tagged Schiff base chemosensor, (E)-N'-((2-aminothiazol-5-yl)methylene)-2-hydroxybenzohydrazide (ATH) has been synthesized in excellent yield by a simple one pot method and characterized by single crystal X-ray diffraction and spectroscopic techniques. The sensing ability of ATH was determined for detection of Hg2+ ions in the presence of different metal ions in aqueous medium. It behaves as an extremely selective and sensitive chromogenic sensor for naked-eye detection of Hg2+ ions with a colour change from colourless to yellow due to ligand to metal charge transfer. Remarkably, the binding constant (Ka) and limit of detection (LOD) for ATHHg2+ complex were found as 1.75 × 104M −1 and 8.85 × 10−7 M, respectively. The Job's plot indicated that the stoichiometric ratio of ATH to Hg2+ is 1:1. The binding mechanism was established based on FT-IR, 1H NMR titration, mass spectrometry and density functional theory studies. The chemosensor exhibited an excellent colorimetric property in 7.0–12.0 pH range. The chemosensor was found to be reversible and reusable in the presence of CN− ions with logic gate behaviour. Further, the chemosensor was utilized to sense Hg2+ ions in tap and Ganga river water samples.

Trace level CN− measurement by ‘turn-on’ emission using Coumarinyl-Benzothiazolyl Schiff base probe in living and non-living environment

Coumarinyl-benzothiazolyl Schiff base (HL) is spectroscopically (FTIR, UV–Vis, NMR, Mass) characterized and the Single Crystal X-Ray Diffraction measurement confirms the structure. The molecule is water insoluble and DMSO solution shows weak emission which may be due to ESIPT assisted H-transfer quenching process. The emission is significantly enhanced in presence of CN−, one of the most toxic anions, through ‘turn-on’ emission (λem = 449 nm; λex = 350 nm) even in presence of many other anions. The mechanism of sensing towards CN− has been described by 1H NMR titration which reveals deprotonation of –OH group and nucleophilic attack to the imine (-CHN-) bond. Further, the Job's plot supports 1:1 molar binding ratio, [HL + CN−] (Kd, 0.696 x 104 M−1) and has been confirmed by ESI-MS. The detection limit (LOD), 0.75 μM, is third best literature. MTT assay of HL shows no-toxicity up to 100 μM and Intracellular Imaging in MDA-MB 231 cell line has been performed for the sensing of CN−.

Cyanide selective colorimetric and turn-on fluorimetric sensing by naphthohydrazide derivative and its application in real sample analysis

Synthesis, characterization of (E)-3-hydroxy-N'-(2-hydroxy-3-methoxybenzylidene)-2-naphthol hydrazide (HNV) and its sensing ofCN− ion have been described in this paper. Probe HNV is formed by the reaction of o-vanillin and 3-hydroxy-2-naphthoic acid hydrazide and is confirmed by FT-IR, 1H NMR and ESI-MS spectrometry. Addition of CN− ion in probe HNV results in the establishment of a new absorption band at 400 nm in UV–visible spectrum and turn-on fluorescent behavior in H2O-DMSO (7:3 v/v) mixed solvent. Fluorescence intensity of probe HNV is found to be enhanced by 13.1 times in presence of CN−. Colorless solution of HNV is converted to yellow on addition of CN− ion and similar change in color is noticed on Whatman filter paper test strips also. Binding mechanism for the probe HNV with CN− is validated using 1H NMR titration. HNV can be applied for the analysis of real water samples..

Photometric and Colorimetric Cyanide Detection Sensor Using Amine Based Nitrobenzoxadiazole Derivatives

AbstractThe fluorescent probes 7‐nitro‐N‐phenylbenzo[c][1,2,5]oxadiazol‐4‐amine (1), and 4‐((7‐nitrobenzo[c][1,2,5]oxadiazol‐4‐yl)amino)benzonitrile (2) were synthesised for the detection of cyanide ion (CN−). A new correlative approach with nitrobenzoxadiazole (NBD)‐based probes to detecting CN− by the Donor‐Acceptor D‐A (1) and Acceptor‐Donor‐Acceptor (A‐D‐A) (2) with the aid of DFT calculations are reported. Given their design features, these NBD probes 1 and 2 provide useful insights into the dual‐channel (fluorometric and colorimetric) sensor activity with good selectivity for CN− detection, considerable fluorescence amplification in the presence of CN− ion, and the desirable “Off–on” fluorescent responses toward CN− in the semi‐aqueous medium. The photophysical studies confirmed the A‐D‐A type molecule has a detection limit 0.163 μM for CN− sensing, which is lower than the WHO′s cyanide in water permitted limit. The simple synthetic probes 1 and 2 will offer up new possibilities for industrial effluent CN− detection and bio‐imaging of CN− in a variety of cell lines. This will undoubtedly aid in the understanding of the basic mechanism of CN− poisoning in the bloodstream.

Synthesis of cationic hydrogels with tunable physicochemical properties for antibacterial applications

Hydrogel materials are the preferred candidates for antimicrobial materials due to their high water absorption, superior biocompatibility and structural diversity. In this work, we present for the first time that diamine-alkyl and 1,3-dibromo-2-propanol can be rapidly cross-linked to prepare a series of new cationic polymer gels by polycondensation reactions under a strongly alkaline environment. The presence of CN+ bonds are demonstrated in the formation of dendritic structured polymers by XPS analysis. In addition, the physicochemical properties of b-PHIs hydrogels were evaluated and it was found that the variation of diamine alkyl chain length could modulate the storage modulus, water uptake properties, thermal stability and zeta-potential of the gels. The increase in hydroxyl content and the CN+/CC ratio is evidenced by the elevated water absorption properties of the gels and the variations in zeta potential, respectively. In addition, the antibacterial performance evaluation showed that gels had good antibacterial activity against S. aureus and E. coli, with antimicrobial rates of b-PHOI as high as 96% and 97%, respectively. This work pioneers a brand-new idea for the simple and rapid synthesis of branched cationic polymers with low cytotoxicity in the field of antimicrobial biomaterials and proceeds a new attempt in the directional modulation of the physical properties of the materials.

Interfacing g-C3N4 Nanosheets with CdS Nanorods for Enhanced Photocatalytic Hydrogen Evolution: An Ultrafast Investigation.

Effective separation of electron-hole and utilization of hot charge carriers are known to be the most important factors influencing the activity of a good photocatalyst. Herein, we developed a 1D/2D heterojunction in the composite of CdS nanorod and g-C3N4 (CN) nanosheets. These two form a quasi-type-II junction at the heterointerface. The photoexcited electrons are supposed to be transferred from CN to CdS, as observed from the enhanced photoluminescence of CdS. Transient studies revealed an absolute dominance of CdS exciton formation even in the composite system, although the dynamics were substantially modified in the presence of CN. The rise time of CdS band edge excitons were increased in the composite material, owing to the migration of hot electrons from CN to CdS. The hot electron transfer time was found to be ∼0.5 ps (rate constant ∼1.98 ps-1). The excitons decay in a much slower manner than that of the pristine CdS, confirming enhanced electron population in CdS. This migration of charge carriers was found to be immensely dependent on the applied excitation photon energy. Efficient migration of charge carriers leads to enhanced photocatalytic activity in the composite and an increased evolution of H2 evolution rate was witnessed. This detailed spectroscopic study toward the mechanistic pathway of the catalytic activity of an 1D/2D heterocomposite would be immensely helpful in fabricating many other effective heterojunctions which will advance the catalysis research.

Unveiling of a smartphone-mediated ratiometric chemosensor towards the nanomolar level detection of lethal CN-: combined experimental and theoretical validation with the proposition of a molecular logic circuitry.

A promising naphthalene-functionalized ratiometric chemosensor (E)-1-((naphthalen-5-yl) methylene)-2-(2,4-dinitrophenyl) hydrazine (DNMH) is unveiled in the present work. DNMH demonstrates brisk discernible colorimetric response from yellow to red in the presence of CN−, a lethal environmental contaminant, in a near-perfect aqueous medium with a LOD of 278 nM. The “key role marker” controlling the electrochemical and non-covalent H-bonding interaction between DNMH and CN− is through the commendable role of acidic –NH functionalities. Kinetic studies reveal a pseudo second order reaction rate and the formation of an unprecedented photostable adduct. The negative value of ΔG as evaluated from ITC substantiates the spontaneity of the DNMH⋯CN− interaction. The sensing mechanism was further reinforced with state-of-the-art theoretical investigations, namely DFT, TDDFT and Fukui indices (FIs). Moreover, the proposition of a reversible multi-component logic circuitry implementing Boolean functions in molecular electronics has also been triggered by the turn-over spectrophotometric response of the ditopic ions CN− and Cd2+. The cytotoxicity of DNMH towards Bacillus thuringiensis and Escherichia coli is successfully investigated via the MTT assay. Impressively, “dip stick” and “easy to prepare” test paper device and silica gel-based solid-phase CN− recognition validate the on-site analytical application of DNMH. Furthermore, the involvement of a synergistic approach between ‘chemistry beyond the molecule’ and ‘engineering’ via an exquisitely implemented smartphone-assisted colorimetric sensory prototype makes this work unprecedented among its congeners and introduces a new frontier in multitudinous material-based functional product development.

A molecular probe layer modified organic thin film transistor on flexible platform for next generation cyanide sensor

Organic thin film transistor (OTFT) based cyanide (CN−) sensor can be of an intense interest due to its simple operation, high sensitivity, system on chip (SoC) integration capacity and applicability towards environmental safety. So, mechanical flexibility of such sensors can extend them to conformable, bio-compatible and wearable applications. In our recent work, a novel OTFT based highly sensitive and mechanically flexible platform was developed to detect CN− in aqueous medium. The sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate by simple spin coating and operated at a very low voltage of −3 V. For the sensing element, a chemically active dansyl-dervatized-triazole linked glucopyranosyl conjugate (DTGC) was used as a molecular probe on the semiconducting poly (3-hexylthiophene) P3HT layer in the device structure. The fabricated sensor was characterized electrically while using an aqueous solution of tetrabutylammonium cyanide (TBAC) as an analyte. Significant changes in device characteristics including 0.4 V shift in threshold voltage, 0.2 cm2v−1s−1 increment in mobility and 2 μA increase in drain current were observed for the OTFT based sensor with presence of CN− analyte. The concentration of the CN− was then varied and thus the minimum detection limit was found to be 1 μM. The sensor also exhibited excellent mechanical flexibility with its stable operation even up to a bending with 5 mm of bending radius. The sensing mechanism of the developed sensor has been explained through the possible charge transfer phenomena from the host semiconductor due to a chemical reaction between the probe layer and the analyte. The sensititvity and chemical reactivity of the molecular probe to the CN− were further confirmed from the microscopic studies and the change in the visual appearance (colour) of the probe with the presence of aqueous CN−.

A robust gold nanocluster-peroxyoxalate chemiluminescence system for highly sensitive detection of cyanide in environmental water

Detection of cyanide (CN-) ion is of essential importance due to its high toxicity to human life. Herein, we developed a gold nanoclusters (AuNCs)-peroxyoxalate chemiluminescence (CL) system for ultrasensitive detection of CN- in environmental water samples. Bis (2,4,5-trichloro-6-carbopentoxyphenyl) oxalate (CPPO)-hydrogen peroxide (H2O2) CL reaction was utilized to produce high energy intermediates, namely energy donors, and AuNCs served as the acceptors to harvest the energy via CL resonance energy transfer (CRET) process. Besides, it was demonstrated that AuNCs also could act as a catalyst to enhance the generation of the high energy intermediate; and the AuNCs also had an aggregation induced emission (AIE) effect in the organic solvent that was used in CPPO-based CL system. In the presence of CN-, AuNCs can be etched by CN- due to the Elsner complexation reaction between CN- and AuNCs, and thus both of the quantum yield and catalytic activity decreased remarkably. As a result, significant quenching of CPPO-AuNCs CL was observed. The CL intensity decreased linearly in the concentration range of 2.5–125 μg/L CN-, and the detection limit was calculated to be 0.55 μg/L, 10-fold lower than that obtained by the fluorescent sensing of AuNCs. The relative standard deviation was 4.3% for seven parallel measurements of 100 μg/L CN-. It also exhibited high selectivity and favorable anti-interference capability. The sensing system was used for detection of CN- in five standard water samples, and the analytical results were in good agreement with the certified values. Overall, the simple and sensitive CL sensing platform offers a promising tool for convenient detection of CN- in environmental water samples.

Cyanide sensitivity in direct electron transfer-type bioelectrocatalysis by membrane-bound alcohol dehydrogenase from Gluconobacter oxydans

An overexpression system of membrane-bound alcohol dehydrogenase (ADH) from Gluconobacter oxydans was constructed to examine its bioelectrocatalytic characteristics. The effects of cyanide (CN−) addition on the kinetics of direct electron transfer (DET)-type bioelectrocatalysis by ADH were analyzed. CN− enhanced the bioelectrocatalytic activity, while the catalytic activity in the solution remained unchanged, even in the presence of CN−. Electrochemical methods and electron spin resonance spectroscopy showed the detailed electron transfer pathway in the DET-type bioelectrocatalysis by ADH. Briefly, ADH is suggested to communicate with an electrode via a CN−-insensitive and H+-sensitive heme c in DET. These characteristics of ADH with respect to CN− suggest the involvement of ADH in CN−-insensitive respiration in G. oxydans.

Synthesis and physical studies of coumarin-based chemosensor for cyanide ions

A series of novel coumarin-based chemosensor azine derivatives L1, L2 and L3 were synthesized and characterized by various spectroscopic methods such as 1H NMR, mass spectrometry, FT-IR and elemental analysis. The sensing property of the sensor L derivatives was confirmed by the UV–Vis absorption, emission spectra and the naked eye sensing. The sensor L derivatives showed the absorption band at 320–330 nm. The fluorescence emission band was observed at 550–560 nm. In the presence of CN− ions, the chemosensor L derivatives show the “turn-on” fluorescence response over the other competing anions such as Br−, I−, HSO4−, ClO4− and PF6−, and the new absorption band appeared at 385 nm and the emission band also shifted to the blue region at 440 nm. The sensor L derivatives bind to cyanide ions in a 1:1 binding stoichiometry calculated from the job’s plot experiments. The detection limit of sensor L1 towards CN− was 5.79 × 10−8 M. Additionally, the binding constant was determined to be 1.0209 × 106 M−1 from the Benesi-Heilbrand equation. The theoretical calculations were performed by Gaussian 9 software. The sensing mechanism of the interaction between the cyanide ion and imine carbon was confirmed by the 1H NMR titration method and mass spectra.