Determination Of Cyanide Research Articles

Determination of Cyanide in Peruvian Cassava by Chemical Techniques

Determination of Cyanide in Peruvian Cassava by Chemical Techniques

Sensitive Electrochemical Sensing Properties for Cyanide Detection Using Polyaniline/Cu-Vanadate Nanobelt-modified Electrode

Background: Cyanide is a toxic anion and may be discarded into the water environment, which is a serious threat to human beings and the environment. Hence, it is essential to explore a facile, sensitive method for cyanide detection. Polyaniline/Cu vanadate nanobelts serve as electrode materials for sensitive cyanide determination. Methods: Polyaniline/Cu vanadate nanobelts were obtained by a simple route using polyaniline, Cu vanadate nanobelts. The polyaniline/Cu vanadate nanobelts were measured via electron microscopy, diffraction, infrared spectrum, and electrochemical methods. Results: Amorphous polyaniline nanoparticles with a particle size of about 100 nm were attached firmly to the surface of Cu vanadate nanobelts. Electrochemical sensing properties for cyanide detection were analyzed using a cyclic voltammetry technique using the nanobelts-modified electrode. The cyclic voltammograms (CV) peaks centered at +0.64 V and +0.54 V were observed using the polyaniline/Cu vanadate nanobelts in 0.1 M KCl solution with 2 mM cyanide. The proposed composite nanobelt-modified electrode possessed the detection range and detection limit of 0.001-2 mM and 0.22 μM, respectively. Conclusion: Polyaniline greatly enhances the electro-catalytic performance of the Cu vanadate nanobelt-modified electrode for cyanide detection.

A highly sensitive colorimetric and fluorometric sensor for the detection of cyanide

Certain anions play a vital role in metabolic reactions in our body, but the cyanide ion is highly toxic and poisonous to humans, animals, and the environment even at extremely low concentrations. To detect CN−ions, a highly sensitive electron donor-π-acceptor molecular system (IC) was designed based on the carbazole electron donor and 1,3-indanedione electron acceptor. The IC molecular probe was synthesized through simple organic transformations with good yields and characterized by all spectroscopic methods, including single-crystal X-ray diffraction. The IC probe molecule absorbs in the UV–visible region (200–550 nm), and fluorescence emission encompasses 400–750 nm with LE and CT emission bands. A systematic study suggests that the addition of cyanide ions caused both longer wavelength absorption bands and CT fluorescence emission intensity to decrease. Cyanide ion detection can be visualized with the naked eye, where the yellow color of the IC probe solution changes to colorless upon adding cyanide ion solution. Both UV–visible and fluorescence emission spectral changes with the addition of cyanide ions are attributed to the nucleophilic addition of cyanide at the vinylic carbon, which is confirmed by the 1H NMR, HRMS and fluorescence lifetime studies. The cyanide ion detection limit of the IC has been estimated to be 0.43 µM, far below the WHO permissible limit for cyanide ion concentration in potable water, thus broadening the utility of the IC probe in detecting cyanide in Tapioca. A prototype TLC testing strip has been fabricated for the qualitative determination of cyanide in THF/water medium.

Alternative Electrochemical Determination of Cyanide Using a Carbon Paste Electrode Modified by Natural Clay in Contact with Moringa Oleifera

Cyanide is increasingly released into the environment as a result of human activities. Once ingested into the body, it blocks vital functions and can lead to death. The aim of this work is to detect cyanide using cathodic stripping voltammetry employing a carbon paste electrode modified with 5% Agban Bingerville clay. Two electrochemical sensors were developed for the detection of cyanide: one with a bare carbon paste electrode and the other with a clay-modified carbon paste electrode. The modified electrode detects cyanide in a hydrochloric acid (pH 1) supporting electrolyte seven times more effectively than the bare carbon paste electrode. Its detection limit is 1.41 µmol/L or 0.04 mg/L, and its sensitivity is 4458 μA cm−2μM−1. This value is below the cyanide concentration limit set by the World Health Organization (WHO) for drinking water. This sensor can therefore contribute to the routine monitoring of environmental matrices. After detection, Moringa oleifera seed powder helps eliminate the cyanide from the solution. The optimum mass of seed powder, which removes 77% of cyanide, is 0.08 g for a 10 mL cell after stirring for 10 min. The elimination occurs as a result of electrostatic interactions between positively charged Moringa proteins and cyanide.

Determination of Cyanide and Cyanoglycosides in Foods Containing Apricot Seeds by HPLC with Fluorescence Detection

Determination of Cyanide and Cyanoglycosides in Foods Containing Apricot Seeds by HPLC with Fluorescence Detection

Construction of Metal-Organic Framework as a Novel Platform for Ratiometric Determination of Cyanide.

Metal-organic frameworks (MOFs) are frequently utilized as sensing materials. Unfortunately, the low conductivity of MOFs hinder their further application in electrochemical determination. To overcome this limitation, a novel modification strategy for MOFs was proposed, establishing an electrochemical determination method for cyanides in Baijiu. Co and Ni were synergistically used as the metal active centers, with meso-Tetra(4-carboxyphenyl)porphine (TCPP) and Ferrocenecarboxylic acid (Fc-COOH) serving as the main ligands, synthesizing Ni/Co-MOF-TCPP-Fc through a hydrothermal method. The prepared MOF exhibited improved conductivity and stable ratio signals, enabling rapid and sensitive determination of cyanides. The screen-printed carbon electrodes (SPCE) were suitable for in situ and real-time determination of cyanide by electrochemical sensors due to their portability, low cost, and ease of mass production. A logarithmic linear response in the range of 0.196~44 ng/mL was demonstrated by this method, and the limit of detection (LOD) was 0.052 ng/mL. Compared with other methods, the sensor was constructed by a one-step synthesis method, which greatly simplifies the analysis process, and the determination time required was only 4 min. During natural cyanide determinations, recommended readouts match well with GC-MS with less than 5.9% relative error. Moreover, this electrochemical sensor presented a promising method for assessing the safety of cyanides in Baijiu.

Spectrophotometric Determination of Cyanide in Passaic River Paterson New Jersey by Distillation and Colorimetric Method with Pyridine: Barbituric Acid Reagent

Purpose: This work determines the concentration of total cyanide in the Passaic River in the New Jersey Area.
 Methodology: The concentration of cyanide and the subsequent reaction of the product with a mixed solution of pyridine-barbituric acid to form a stable complex. Therefore, before chlorination of cyanide, all cyanide compounds present in sample must be broken down by an acid reflux and distillation.
 Findings: The cyanide concentration in the Passaic River sediment solution and non-running wastewater was determined by measuring absorbance at max 578 nm, and cyanide amount has been found less than 0.005 ppm under the NEPA permit compliance. Industrial facilities who discharge wastewater to public waterways in the United States, stringent limits on cyanide, typically with monthly average effluent limits set around 0.005 ppm or less.
 Unique contributor to theory, policy and practice: This method is applicable to the determination of cyanide in drinking, saline, groundwater, surface water as well as domestic and industrial wastewater.

Modification of sensitive pyridine-pyrazolone method for determination of blood cyanide and its possible applications in fatal aircraft accidents

BackgroundFatal aviation accidents are a critical concern for armed forces, necessitating precise toxicological analysis of postmortem blood samples. This paper introduces a novel spectrophotometric method for quantifying cyanide in blood samples with an aim to aid in aircraft accident reconstruction in the future. MethodsBlood samples were collected from healthy non-smokers aged 20–45 years, excluding individuals with hepatic impairment, or those using drugs affecting blood cyanide levels. The spectrophotometric method involved cyanide adsorption in a sodium hydroxide solution using microdiffusion discs and chemical reactions resulting in a pinkish-purple end product. The optimal absorption wavelength (λmax) was determined, and the lower limits of detection and quantitation were established. The method underwent validation for precision, sensitivity, specificity, linearity, and accuracy. ResultsThe procedure yielded a pinkish-purple compound with an optimal absorption wavelength (λmax) of 531 nm. The established limits of detection (LoD) and quantitation (LoQ) were 0.0625 μg/ml and 0.125 μg/ml, respectively. The method demonstrated strong linearity up to cyanide concentrations of 4 μg/ml. It exhibited a sensitivity of 99.7% and accuracy of 85.92%. The intraday and inter-day precision were determined as 9.04% and 4.27%, respectively. The method was highly specific, showing no interference with blanks at the peak wavelength with a working range of 0.125–4 μg/ml. ConclusionThe study describes developing and validating a sensitive method for quantitatively estimating cyanide in blood samples. Incorporating this method into the existing postmortem toxicological sample collection and investigation protocol will enhance the analysis capabilities and improve aircraft accident investigation outcomes within the country.

The stability of cyanide in human biological samples. A systematic review, meta-analysis and determination of cyanide (GC-QqQ-MS/MS) in an authentic casework 7 years after fatal intoxication

A 30 year old man was found with no signs of life in front of the house. The cyanide concentration in blood and urine was determined five years after the man’s death. What is more, a stability study was conducted for 730 days in an authentic casework blood sample. Sample preparation procedure included precipitation with methanol:water mixture, solid phase extraction (SPE) and derivatization with the use of PFB-Br (pentafluorobenzyl bromide). The sample was analyzed using GC-QqQ-MS/MS (gas chromatopraphy coupled with tandem mass spectrometry) isotope dilution method. Separation was done using a SH-RXI-5MS column (30 m x 0.25 mm, 0.25 µm). Detection of PFB-CN and PFB-13CN was achieved using a triple-quadrupole mass spectrometer with an electron ionization (EI) ion source in multiple reaction monitoring (MRM) mode. After 5 years from the man’s death, cyanide concentration was: 1900 ng/mL in blood and 500 ng/mL in urine. Stability study performed in an authentic blood sample 6 and 7 years after the man’s death revealed cyanide concentrations of 1898.2 ng/mL and 1618.7 ng/mL, respectively. While spectrophotometric and colorimetric methods recorded both decrease and increase in cyanide concentration over time, newer chromatographic methods mainly indicate a decrease. The studies presented in this paper seem to confirm this trend. However, in order to interpretate the results of cyanide concentration in biological material reliably, more research is still necessary.

A New Azomethine Chemosensor for Naked-Eye Detection of CN− and AcOˉ: Application to Determination of Cyanide in Some Agro-Products and Poisoned Human Blood Samples

A new symmetrical azomethine probe, H2L, has been synthesized via a condensation reaction of N, N´-Ethylene bis (3-formyl-5-methyl salicylaldimine), with Isonicotinic hydrazide in EtOH. The anion recognition studies exhibited that H2L acts as a chemosensor for the detection of CN− and AcO− in pure DMSO and DMSO/H2O 90:10(V/V) media over other basic anions such as F−, Cl−, Br−, I−, N3 −, SO4 2−, SO3 2−, PO4 3−, H2PO4 −, HSO4 −, NO2 −, and NO3 −. The ability of the H2L for rapid colorimetric sensing of CN− and AcOˉ was studied using UV–Vis, and 1H NMR titration methods. The detection limits of H2L toward CN− and AcO− in the semi-aqueous medium were found to be 2.12 and 2.63 μM, respectively, which are lower than the LOD of some existing azomethine probes. Effectively, H2L was used to qualitatively and quantitatively detect cyanide ions in the human-poisoned blood and some of the agro-products containing cyanogenic samples without relying on expensive instruments.

A sensitive biosensor for cyanide detection using modified glassy carbon electrode with reduced graphene oxide and immobilization of horseradish peroxidase

AbstractCyanide is a highly poisonous and hazardous substance which may release into the environment from natural sources or industrial effluent; therefore, cyanide detection is a fundamental step to prevent environmental pollution and secure health and safety. In this study, we prepared a sensitive amperometric inhibition biosensor for cyanide detection by immobilization of horseradish peroxidase (HRP) enzyme and reduced graphene oxide (rGO) on the surface of glassy carbon electrode (GCE). To do so, we performed the amperometric measurement by modified GCE to test its efficiency in detecting cyanide. The optimum conditions of pH equal to 7.5, −100 mV applied potential, 0.7 μM mediator concentration, and 0.5 mM substrate concentration were found. Then, experiments were performed at different boundary conditions in a range of 0.1 to 10 μM cyanide concentration at optimal conditions and a low detection limit of 0.01 μM was obtained. Also, the possible mechanism of inhibition was analyzed based on the Michalis–Menten equation and non‐competitive inhibition was observed. Due to high sensitivity, low detection limit, and low cost, this biosensor is proposed as a useful method for cyanide determination in real samples.

Combination of headspace single-drop microextraction (HS-SDME) with a nickel-embedded paper-based analytical device for cyanide quantification

BackgroundCyanide anion can be found in foodstuffs, tobacco smoke and a variety of types of waters, mainly originating from anthropogenic activities. Due to its highly toxic nature, several agencies have established limits for cyanide levels in water. Additionally, monitoring cyanide levels in biological samples, such as blood and urine, is crucial for obtaining clinical information about the health condition of patients. Therefore, there is a pressing need for the development of simple, cost-effective, and reliable analytical methods capable of quantifying cyanide at low concentrations. ResultsThis study presents a novel analytical method for the selective and sensitive determination of cyanide based on analyte volatilization, pre-concentration via single-drop microextraction (SDME) using a selective reagent, and colorimetric quantification using a paper-based analytical device. For this, 10 mL of a liquid sample was acidified with phosphoric acid and the generated HCN was collected using a single drop of 3 μL of a palladium dimethylglyoximate solution (Pd (DMG)22−) positioned in the flask headspace using a syringe. The reaction of Pd (DMG)22− leads to the formation of Pd(CN)42− and the demasking of the organic ligand. After 15 min of extraction time, the reagent drop was added to a paper-based analytical device that has been previously impregnated with 3 μL of nickel chloride, resulting in the formation of a red precipitate of nickel (II) dimethylglyoximate. Digital images of the paper-based device were captured and the red channel (R) was used for quantification purposes. Under optimized conditions, the method demonstrates a suitable linear relation (r2 > 0.99) ranging from 26 to 286 μg L−1 and a limit of detection of 5 μg L−1. SignificanceAs a proof of concept, cyanide levels were quantified in water and urine samples using this method. The proposed approach offers high sensitivity and selectivity while requiring only a small volume of reagents. Furthermore, it exhibits a high degree of portability for in-situ applications.

Concurrent determination of cyanide and thiocyanate in human and swine antemortem and postmortem blood by high-performance liquid chromatography-tandem mass spectrometry.

Cyanide (in the form of cyanide anion (CN-) or hydrogen cyanide (HCN), inclusively represented as CN) can be a rapidly acting and deadly poison, but it is also a common chemical component of a variety of natural and anthropogenic substances. The main mechanism of acute CN toxicity is based on blocking terminal electron transfer by inhibiting cytochrome c oxidase, resulting in cellular hypoxia, cytotoxic anoxia, and potential death. Due to the well-established link between blood CN concentrations and the manifestation of symptoms, the determination of blood concentration of CN, along with the major metabolite, thiocyanate (SCN-), is critical. Because currently there is no method of analysis available for the simultaneous detection of CN and SCN- from blood, a sensitive method for the simultaneous analysis of CN and SCN- from human ante- and postmortem blood via liquid chromatography-tandem MS analysis was developed. For this method, sample preparation for CN involved active microdiffusion with subsequent chemical modification using naphthalene-2,3-dicarboxaldehyde (NDA) and taurine (i.e., the capture solution). Preparation for SCN- was accomplished via protein precipitation and monobromobimane (MBB) modification. The method produced good sensitivity for CN with antemortem limit of detection (LODs) of 219 nM and 605 nM for CN and SCN-, respectively, and postmortem LODs of 352 nM and 509 nM. The dynamic ranges of the method were 5-500µM and 10-500µM in ante- and postmortem blood, respectively. In addition, the method produced good accuracy (100 ± 15%) and precision (≤ 15.2% relative standard deviation). The method was able to detect elevated levels of CN and SCN- in both antemortem (N = 5) and postmortem (N = 4) blood samples from CN-exposed swine compared to nonexposed swine.

Colorimetric Sensor Based AgNPs for the Detection of Cyanide using UV‐Vis Spectrophotometry

AbstractCyanide (CN−) is known to be a very harmful ion that may accumulate in the air, soil and water, and become a critical risk to organisms, even at trace levels. Hence, it is very critical to develop sensitive and accurate analytical methods for the determination of this anion. In this study, a highly sensitive and simple approach was developed for the quantitative determination of cyanide by UV‐Vis spectrophotometry with the aid of synthesized silver nanoparticles (AgNPs) solutions. AgNPs are promising probes frequently used in the determination of both organic and inorganic pollutants. The AgNPs were prepared by reducing silver nitrate (AgNO3) with sodium borohydride (NaBH4) in the presence of Triton X‐100 as a stabilizer. The UV‐Vis absorption spectra showed that the interaction between cyanide ions and AgNPs made significant decreases in the absorption peak of the surface plasmon resonance (SPR) band at 405 nm. The developed colorimetric sensor exhibited exceptional sensing towards cyanide ions with good linearity in the range of 0.5 and 3.5 mM. The limit of detection (LOD) and the limit of quantification (LOQ) were estimated as 0.09 and 0.29 mM, respectively. Moreover, the proposed colorimetric method was successfully applied to different water samples.

Growth of Carbon Nanotubes on Metallic Substrate: Growth Mechanism and Electrochemical Applications

This work reports the use of carbon nanotubes-modified silver (CNTs-Ag) electrode prepared by chemical vapor deposition (CVD) as indicating system in differential electrolytic potentiometry (DEP) for both redox and precipitation reactions. Characterization of CNTs-Ag electrode by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed the formation of aligned CNTs of a good degree of crystallinity and well-graphitized sheets. CNTs-Ag electrode was applied successfully for the determination of ascorbic acid in both pure form and in pharmaceutical and food samples along with in the determination of cyanide too down to quite low concentrations. CNTs-Ag electrode exhibited a fast and stable response and attained equilibrium in a short time. These good characteristics are attributed to the rapid heterogeneous electron transfer and high electrode surface area offered by CNTs. Additionally, modification of the Ag with CNTs grown via CVD method offers adhesion of the CNTs layers to the Ag surface and direct electrical contact better than the external modification methods commonly used such as casting the CNTs or mixing them with Nafion. Moreover, CVD method offers the chance to produce aligned CNTs that have better electrical properties than the randomly distributed ones. This work also proposed a CNTs growth mechanism by XPS depth profiling analysis. Figure 1

Morphological Characterisation and Cyanide Content Determination in Phaseolus lunatus Linn. (Lima Beans) Accessions

Lima bean (Phaseolus lunatus Linn.) is one of the important legumes in developing countries. The study was carried out to evaluate the morphological characters and determine the amount of cyanide in lima beans. A total of 15 Lima bean accessions were obtained from the genebank of Genetic Resource Centre, International Institute of Tropical Agriculture (IITA) Ibadan, Oyo state, Nigeria and laid in Complete Randomised Design with three replicates. Morphological characters were evaluated based on the descriptors proposed by the International Plant Genetic Resources Institute, while hydrogen cyanide (HCN) content was determined using alkaline picrate colorimetric method. Six of the accessions (2005-014, 2006-003A, 2006-003B, 2006- 005A, PS-16 and TPl-2429) having best yield, moderate yield and lowest yield were selected for cyanide determination. Result showed that the accessions varied morphologically. The highest yielding accessions were TPl-2429, 2005- 014, 2006-003A and 2005-011, while 2006-003B and TPl-178 have moderate yields. Accession 2005-014 had the highest growth characters, followed by 2006-015 and 2006-003A which showed good quality. Lower amounts of cyanide were detected in 2005-014 and PS-16 accessions, while 2006-003A, 2006-003B and 2006-005A accessions did not show cyanide contents. Therefore, TPl-2429, 2006-003A and 2005-011 accessions which showed higher growth and yield with no cyanide content could be further improved in breeding of lima beans.

Determination of Cyanide and Cyanoglycosides in Sweetened Bean Paste by HPLC with Fluorescence Detection.

It is necessary to evaluate the efficiency of reduction for cyanide and cyanoglycosides during the manufacturing process from raw material beans to sweetened bean paste in a food hygiene control system from the viewpoint of food safety. Analytical methods for cyanide and cyanoglycoside determination in sweetened bean paste by HPLC with fluorescence detection were developed. In analysis of collection time of free cyanide in the free cyanide assay, the recovery was improved by extending the collection time, the recovery rate was >80% by 2 h. The accuracy, repeatability and intra-laboratory precision of the free cyanide assay were 82.3, 2.0, and 2.4%, respectively. The method for cyanoglycoside analysis was evaluated by 5 repeated spiked recovery experiments at a concentration of 10 ppm. The accuracy, repeatability and intra-laboratory precision of the cyanoglycoside method were 82.2, 1.9, and 3.4%, respectively. These analytical methods will enable the analysis of cyanide and cyanoglycosides in sweetened bean paste without using steam distillation method in the pretreatment.

Determination of Cyanide at Trace Levels by Computational Scanning Densitometry

Introduction: Cyanide is one of the most commonly present anions in industrial effluents, highly toxic to human and animal life. Therefore, its determination in aqueous media by simple, portable, and quick methods is required. Objective: This study aims to develop a simple and quick method to determine this anion at the micro level in aqueous media without using any expensive instrument. Method: The method is based on treating the microliter sample of aqueous cyanide with the classical Lassaigne’s reagents on a TLC plate. After heating in an oven for a few minutes, a deep blue spot of ferric ferrocyanide complex appeared on the plate. The color depth of the spots was measured by scanning the TLC plate and analyzing the image with an indigenous software package. Result: As a result of fusion with metallic sodium, carbon and nitrogen of the organic compound combine to form cyanide, which first reacts with Fe(II) to form hexacyanoferrate ion [Fe(CN)6]4- that further combines with Fe(III) to create a neutral deep blue colored coordination complex, ferric ferrocyanide Fe4[Fe(CN)6]3. Discussion: This process converts real-world colors into numeric computer data consisting of rows and columns of pixels. Each pixel will consist of three numeric components, i.e., red, green, and blue. The pixel's color will be one of 16.8 million possible color combinations (256 shades of red, green, and blue each). Conclusion: From the comparison of results obtained by the proposed method and standard ion-selective electrode method, it can be concluded that the former method for determining micro quantities of cyanide in aqueous samples using computational densitometry is a simple, accurate, and adequately precise method without the involvement of sophisticated instrumentation.

Nitrogen-Doped Graphene Quantum Dots as “Off–On” Fluorescent Probes in Paper-Based Test Kits for Selective Monitoring of Cyanide in Food

We successfully developed a fluorometric paper-based test kit for the selective and sensitive determination of cyanide using nitrogen-doped graphene quantum dots (N-GQDs) as the fluorescent probe. Citric acid and tris(hydroxymethyl)aminomethane were precursors for the one-step synthesis of N-GQDs via in situ hydrothermal methods, providing a high quantum yield of 57.9%. The proposed mechanism uses a fluorescence turn-on approach. Specifically, the fluorescence of N-GQDs is quenched by the incorporation of Ag+ via a photoinduced electron transfer (PET). During the detection step, sulfuric acid converts cyanide (CN–) into hydrogen cyanide (HCN). The Ag+ species on the N-GQD surface then react with the evolved HCN via a coordination bond to form a silver cyanide complex, resulting in the fluorescence emission of the N-GQDs being turned back on. As a result, the fluorescence emission intensity of N-GQDs linearly increased with increasing CN– concentrations in the range of 0.5–25 mg L–1, with a limit of detection (LOD) of 0.08 mg L–1. Notably, the developed sensor has advantages in terms of simplicity, rapidity, low cost, and high selectivity toward CN–. The analytical performance of the test kit was also validated the performance of the test kit against a conventional precipitation titration method.

Enhancing the Cyanide Sensing Performance of the CuBi2O4 Nanoflakes by Polyaniline

Background: Cyanide (CN-) belongs to dangerous anion pollutants owing to its toxicity at low level. The development of an efficient method for the cyanide detection in aqueous solution is of tremendous importance for protecting the environment and human health. Polyaniline/CuBi2O4 composite modified electrode possesses good electro-catalytic activity towards cyanide. Objective: The aim is to synthesize polyaniline/CuBi2O4 nanoflakes by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials, and research the electro-catalytic activity towards cyanide of the composite nanoflakes. Methods: Polyaniline/CuBi2O4 nanoflakes were synthesized by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials. The structure, morphology, chemical bonding and electro-catalytic activity towards cyanide of the composite nanoflakes were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and electrochemical measurements. Results: The obtained composite nanoflakes are composed of tetragonal CuBi2O4 phase. Amorphous polyaniline nanoscale particles with the size of about 50 nm attach to the surface of the CuBi2O4 nanoflakes. The nanoflakes modified glassy carbon electrodes (GCEs) were used for the determination of cyanide. A pair of quasi-reversible cyclic voltammetry (CV) peaks are located at +0.25 V and +0.33 V, respectively at the polyaniline/CuBi2O4 nanoflakes modified GCE. The linear range and detection limit are 0.01-2 mM, 3.1 μM and 0.001-2 mM, 0.39 μM for CuBi2O4 nanoflakes modified GCE, and polyaniline/CuBi2O4 nanoflakes modified GCE, respectively. Conclusion: Polyaniline/CuBi2O4 nanoflakes modified GCE shows good reproducibility and stability for cyanide detection. The electro-catalytic activity towards cyanide of the CuBi2O4 nanoflakes modified GCE can be greatly enhanced by the polyaniline.