Microdetermination of Cyanide

Abstract

A volumetric procedure is described for the micro-determination of cyanide. Small amounts of cyanide can be estimated even in presence of chloride if it is present in the electrolytic bath. N-Bromosuccinimide (NBS) is used to quantitatively oxidized cyanide to cyanate. The end point is reached when the rose red color of the bordeaux red is changed to distinct yellow. From 1–6 mg. of cyanide were analyzed with an average relative standard deviation of about 0.66%.     

Study of Cyano-Derivatives of Propene as Transfer Agents in Radical Polymerizations

ABSTRACT

A new procedure for determining transfer constants, depending on knowledge of the numbers of initiator fragments in the average molecules of appropriate polymers, has been applied to crotononitrile (1-cyano-1-propene) and allyl cyanide (3-cyano-l-propene) with methyl methacrylate and styrene at 60°C. Allyl cyanide is the more reactive of the two additives, but is less effective than allylbenzene (3-phenyl-1-propene); neither of the cyano-derivatives causes appreciable retardation.     

A New Spectrophotometry Determination of Cyanide by Solvent Extraction as Tris-(1,10-Phenanthroline)-Iron (II)-Thiocymate

Abstract

By shaking aqueous cyanide solution with nitrobenzene contained sulfur, thiocyanate is formed and is extracted into the nitrobenzene as an ion pair of thiocyanate anion and tris-(1,10-phenanthroline)-iron(II) chelate cation. By measuring the color intensity of the organic phase at 516 nm, cyanide is determined spectrophotometrically. A linear calibration curve is obtained up to 4 × 10^?5M of cyanide in the aqueous phase.     

Coulometric Determination of Total Cyanide in Effluent and Wastewater

Abstract

A simple procedure for the determination of low levels of total cyanide in effluent samples has been developed. After distillation of the cyanide from the sample, as hydrocyanic acid, the cyanide is determined with coulometrically generated iodine using a biamperometric end point detection system. As little as 0.06mg/l total cyanide can be measured using the procedure. The method obviates the need for calibration curves and does not require special reagents.

Silver (I) was determined to be an effective catalyst for the decomposition of bound cyanides in the distillation procedure.     

Didodecyldimethylammonium Bromide Bilayer Vesicle-Catalyzed and Uranine-Sensitized Chemiluminescence for Determination of Free Cyanide at Picogram Levels by Flow Injection Method

Abstract

A novel chemiluminescence system, didodecyldimethylammonium bromide-uranine-sodium hydroxide, is described for the determination of ultratraces of free cyanide by flow injection method. Organized surfactant assemblies(bilayer vesicles) incorporated with a sensitizer (uranine) permit the determination of free cyanide very selectively with a limit of determination of 1 pg (20-μ1 sample injection). Sulfide, the strongest CL inducer after free cyanide, provides a signal 0.1 % of that for free cyanide.     

Determination of Free Cyanide in Water by Released Flourescence of a Dissociated Ternary Complex

Abstract

A flourometric procedure for the analysis of free cyanide is described. The method is based on the dissociation of a ternary complex of silver-1, 10-phenanthroline-tetrabromofluorescein by cyanide to produce a fluorescent product. The fluorescence intensity is found to be directly proportional to the cyanide concentration. The method can reliably detect 0.02 μg/mL cyanide.     

Continuous Determination of Free Cyanide by Means of Membrane Diffusion of Gaseous HCN and An Electrode Indicator Technique

Abstract

A continuous measurement system for free cyanide has been developed based on the principle of diffusion across a gas-permeable membrane to affect the separation of hydrogen cyanide from the acidified sample solution. The cyanide absorbed in the alkaline indicator solution is subsequently analyzed by an indirect technique using a silver ion-selective electrode. In the concentration range of 30 to 400 μg CN^?/L, the accuracy and precision of this method is approximately two percent. The detection limit of this system is approximately 0.5 μg CN^?/L.     

THE REACTION OF O-SILYLATED α-KETOLS WITH TRIMETHYLSILYL CYANIDE

Abstract

The reactions of a series of O-silylated α-ketols with trimethylsilyl cyanide have been investigated. Formation of the expected 0-trimethylsilyl cyanohydrins as major products has been shown to be accompanied by the hitherto unsuspected formation of a disiloxane by a proposed intramolecular S_N2 displacement mechanism. The latter reaction is, surprisingly, independent of the substitution pattern in the silylated ketol. Formation of the side-product, however, increases in all cases with increasing dilution. The α,β-epoxynitrile 9, a second side-product expected, along with the observed disiloxane, by our proposed mechanism was synthesized by an unambiguous route. A control experiment showed the epoxynitrile to be completely destroyed under the usual conditions of reaction with trimethylsilyl cyanide. ¹³C NMR data have been obtained for most of the compounds in this study.     

Automated Colorimetric Method for Total Cyanide in Water and Wastewater

Abstract

An automated benzidine-pyridine method for the analysis of total cyanide is described. Cyanides are converted to cyanogen bromide by the reaction with bromine water. Cyanogen bromide reacts with benzidine in a dilute pyridine medium to form an intense red color directly proportional to the cyanide concentration. Cyanide often is found complexed with metals. Complex iron cyanides such as ferrocyanide or ferricyanide are difficult to decompose, but the conversion is hastened with mercuric chloride and magnesium chloride in a modified Serfass distillation.¹

Hydrogen cyanide is readily formed and absorbed in sodium hydroxide.     

An Atomic Absorption Analysis Method for Cyanide

Abstract

An atomic absorption analysis procedure for cyanide has been developed. The procedure is based upon the solubilization of copper(II) from a basic copper carbonate in an alkaline medium. The amount of copper complexed by the cyanide ion is determined by atomic absorption and a calibration curve is constructed concurrently. The stoichiometry of the cyanide-copper complex is 3:1, implying formation of the complex ion Cu(CN)^? ₃, with no formation of CuCN observed at the low concentration of cyanide used. The method is used primarily for analyzing low levels of cyanide; the sensitivity of the method extending down to 2.0 × 10^?5 M CN^?. The most likely interference, iron, is considered. Finally, recovery of cyanide from spiked samples is demonstrated.     

A highly selective and sensitive dual-channel chemosensor for cyanide based on sulfahydrazone derivative

A colorimetric and fluorescent cyanide probe bearing naphthol and sulfahydrazone groups has been designed and synthesized. This structurally simple probe displays a rapid response and high selectivity for cyanide in DMSO/EtOH (v/v = 2:8) solution. The addition of CN^? to the sensor p-toluenesulfonyl-2-hydroxy-1-naphthylhydrazone (L3) induced a remarkable color change from pale-yellow to yellow, and green fluorescence changed to yellow. The ¹H NMR titration and DFT calculations suggested that the selective sensing process is based on a nucleophilic addition reaction of cyanide to imine. Test strips based on sensor L3 were fabricated, which could act as a convenient and efficient test kit to detect CN^? for “in-the-field” measurements.     

A Fluorimetric Method for the Determination of Cyanide with Fluorescein and Iodine∗

Abstract

A rapid, simple and sensitive fluorimetric method has been developed for the determination of cyanide with fluorescein as fluorogenic reagent (λ_ex = 494 nm, λ_em = 514 nm) at pH 6.0–7.0. A linear calibration curve was obtained in the range 0.004–2.0 μg CN^?/25 ml. The detection limit is 0.004 μg CN^-/25 ml. The method was successfully applied to the determination of cyanide in waste water.

     

Cyanide by Prussian Blue Spot Formation

Abstract

A simple quantitative test for cyanide is described. Cyanide is released as the hydrocyanic acid and conducted through a prepared disk to form a prussian blue spot. This spot is visually or instrumentally compared to standard spots. Two μg of cyanide can be detected by this method.     

A Modified Method for Measuring Cyanide in Biological Specimens

Abstract

The use of cyanide generating substances for medical, home and business applications has necessitated the need for measuring sublethal levels of this substance because of the potential of inadvertent cyanide poisoning. The method we propose provides a means for more accurate recovery at an increased rate of reaction there by making its sensitivity more conducive to the measurement of minute quantities of cyanide.     

Determination of Cyanide Ion by Derivatization-Gas Chromatography

Abstract

A new gas chromatographic method is described for the determination of cyanide ion in water. Cyanide is converted to benzonitrile by reaction with aniline, sodium nitrite, and copper(II) sulfate. The resulting benzonitrile is extracted into chloroform and determined by gas chromatography with a flame ionization detector. The influences of several ions which may coexist with cyanide on this gas chromatographic method were investigated briefly.     

Argentometric Determination of Cyanide in the Presence of Dithionite

Abstract

Cyanide can be measured in the presence of dithionite and its decomposition products by the method of Liebig-Deniges after treatment of the sample with excess iodine, followed by sulfite. The iodine oxidizes dithionite, sulfite and thiosulfate to sulfate at pH 10. Any cyanide present in the sample will form iodine cyanide. Sulfite reduces excess iodine to iodide and converts cyanogen iodide to iodide and cyanide. A large amount of iodide in the sample shifts the end point of the titration significantly. An appropriate blank must be carried through the procedure to correct for the excess iodide.     

Lithium Perchlorate Mediated Three‐Component Preparation of α‐Aminonitriles Under Solvent‐Free Conditions

Abstract

A three‐component reaction between aliphatic or aromatic aldehyde, an amine and trimethylsilyl cyanide mediated by solid LiClO₄, gave amino nitriles in good to excellent yields. The reaction proceeded smoothly under solvent‐free conditions without any side products.     

Anilinopyridine–metal complexes for the selective chromogenic sensing of cyanide anion

Abstract

Probe 1, which contains an anilinopyridine chromophore and an aza-oxa macrocyclic subunit, presented an absorption band centered at 340 nm in acetonitrile. Addition of Fe(III), Cr(III) and Hg(II) induced the growth of a new absorption band at 430 nm (with color change from colorless to yellow), whereas in the presence of Cu(II), Zn(II) and Pb(II), less marked changes were observed. The color changes observed upon addition of Fe(III), Cr(III) and Hg(II) were ascribed to the formation of 1:1 stoichiometry complexes with probe 1. Coordination of Fe(III), Cr(III) and Hg(II) with the pyridine fragment of 1 induced an enhancement of the charge transfer character accompanied with a marked bathochromic shift that was reflected in a color change from colorless to yellow. The strength of the interaction between probe 1 and Fe(III) cation was modulated upon interaction with anions. Of all the anions tested, only cyanide was able to induce the bleaching of the yellow 1·Fe(III) complex solution. This bleaching was ascribed to the formation of 1·Fe(III)-CN complex that restored, to some extent, the optical features of the free probe allowing the chromogenic sensing of cyanide. Besides, 1·Fe(III) complex was used to detect cyanide in acetonitrile-water 90:10 v/v mixtures with good recoveries.     

Spectrophotometric determination of cyanide by chromogenic disulfide in water using micellar catalysis

A spectrophotometric method is developed for the determination of cyanide in aqueous solutions using chromogenic disulfide 4,4′-2bis(1-hydroxy-3,6-disulfo-8-chloro-2-naphthylazo)diphenyldisulfide (BAS-chlorine) in the presence of cetyltrimethylammonium chloride (CTMAC). The use of CTMAC allows diminishing the limit of detection for the spectrophotometric determination of cyanide to (7.2 ± 0.3) ng/mL (p = 0.95, n = 5, RSD = 29%).     

The Determination of Low Levels of Cyanide Ion Using a Silver Responsive Ion Selective Electrode

Abstract

An analysis of the potentiometric titration curves for the silver-cyanide system indicates two possible approaches to the determination of cyanide ion at low levels. Both involve an indirect measurement of the silver ion in equilibrium with argentocyanide complex. These procedures are considerably more sensitive than the conventional method using a “silver iodide” cyanide responsive electrode.