Silver Dithizonate Research Articles

Determination of mercury by displacement substoichiometric extraction with labeled silver dithizonate in chloroform

A radiochemical displacement method for the determination of small amounts of mercury has been developed. The method involves the displacement of spiked ( 110mAg) silver from its dithizonate complex in chloroform. The effects of various ions on the extent of displacement are reported. By this process, ∼80 μg of Hg(II) can be determined. The results of this method are highly reproducible.

Silver Colloids and Macroemulsions of Metal Interfacial Colloidal Films: Interaction with Dithizone

We discuss macroemulsions stabilized by silver interfacial colloidal films and the effect of dithizone on them. These emulsions are characterized by a very sharp size distribution. We find that dithizone, which is known for its strong interaction with silver, strongly affects the state of flocculation of the colloid. The size of the flocs can be related quantitatively to the droplet size. Dithizone also affects the rate of nucleation of the colloid, which is also expressed in a measurable reduction in the droplet diameter. The adsorption of dithizone on silver hydrosols and organosols and its spectroscopy are also studied. Using Raman spectroscopy, we find that dithizone adsorbs on hydrosols in a structure similar to that of silver dithizonate. S-atom and azo-N-atom bonds with silver are formed in an end-on, perpendicular orientation. In the interfacial colloid the dithizone is present predominantly in a disulfide form.

Spectrophotometric Determination of Silver in Glass and Ceramic Materials by Foam Extraction

Abstract A simple spectrophotometric method has been developed for determination of silver in special glasses. The method involves decomposition of glass with hydrofluoric acid and nitric acid, formation of primary Ag(I)-dithizonate in 0.05 M nitric acid and 1 × 10−5 M dithizone, extraction of silver dithizonate on polyurethane foam, elution with acetone and measurement of absorbance at 500 nm of the colour formed by its secondary complex in ammoniacal acetone medium. The method obeys Beer's law from 0.1 μg Ag/ml to 6.0 μg Ag/ml. The molar absorptivity has been found to be 3.45 × 104l mole−1 cm−1 at 500 nm.

Photochromism of silver(I) and mercury(II) dithizonates : Effect of excess of free ligand on the return to ground state and effect of silver(I) dithizonate on the return of mercury(II) dithizonate

The energy of photons producing highest yield in the photochromic excitation of both silver(I) and mercury(II) dithizonate is shown to be centered around 520 nm. The effect of silver(I) dithizonate on the return of the excited form of mercury(II) dithizonate to the ground state is described. The accelerating effect of the silver complex is interpreted by an empirical kinetic model that takes into consideration the concurrent excitation and relaxation of both complexes. As observed in the photochromism of mercury(II) dithizonate, the presence of excess of ligand proportionally hastens the relaxation of silver(I) dithizonate to the ground state.

Colorimetric Determination of Acetylenic Hypnotics by Formation of Silver Acetylides

A colorimetric method is described for the determination of certain mono-substituted acetylenic hypnotic drugs--ethinamate, methyl pentnol carbamate, and ethchlorvynol. Silver acetylide is formed and extracted into isobutyl methyl ketone. After acidification, an equivalent amount of silver ions is liberated which is assayed colorimetrically as silver dithizonate (lambda mx. 472 nm). About 10--50 microgram compound could be assayed with good accuracy. The procedure is reproducible and precise (standard deviation 1.5--2.19%). The procedure was successfully applied to different pharmaceutical dosage forms.

Static and dynamic isotope exchange separations on hydrophobic organic phases immobilized in plasticized open-cell polyurethane foams

The preparation of TBP-plasticized polyurethane foam containing iodine or silver dithizonate was described. Rapid isotope exchange separations of radioiodide and radiosilver on the plasticized iodine and silver dithizonate foams, respectively, were achieved by batch and column techniques. The effect of various factors on the exchange yield of radioiodide and radiosilver on the proposed reagent foams were critically investigated. The mobility of iodide ion in the iodine foam was proved to be high enough so that all the iodine coated membranes of the foam material are participating in the isotope exchange reaction and the equilibrium attained rapidly.

Direct stripping voltammetric determination of lead, cadmium and zinc dithizonates

A procedure is described in order to determine lead, cadmium and zinc dithizonates by stripping voltammetry. The polarographic analysis is performed in a medium of methanol and benzene (chloroform) in a ratio of 7:1 and in the presence of silver dithizonate. Sodium nitrate was used as a base electrolyte. By carrying out these analytic conditions it is possible to perform directly the stripping voltammetric analysis in benzene (chloroform) solution of extracted dithizonates, without further treatment. Silver nitrate in methanol is added to dithizonates in order to free lead, cadmium, and zinc from their complexes, to be determined polarographically.

Studies with dithizone: Part XXV . The deterioration of stock solutions and the identification of two oxidation products

The deterioration of solutions of dithizone in organic solvents is reviewed and shown to be due to a multiplicity of photochemical and oxidative reactions. Bis-1,5-diphenylformazan-3-yl disulphide has been isolated and characterised as a product of the action ( inter alia) of aqueous iodine upon dithizone or silver dithizonate. Its spontaneous thermal cleavage to give an equimolar mixture of a meso-ionic compound 2,3-diphenyl-2,3-dihydrotetrazolium-5-thiolate and dithizone is shown to explain the partial regeneration of deteriorated solutions of dithizone when treated with reducing agents. The reactions of the disulphide towards a variety of reducing agents and to cleavage by metal cations is reported. The identity of Fischer's diphenylthiocarbazide, Bamberger's tetrazolium betaine and Ogilvie and Corwin's dehydrodithizone with the orange meso-ionic compound obtained from dithizone by using such oxidants as hydrogen peroxide, potassium permanganate, iodobenzenedichloride and iron (III) or thallium (III) was established by ultimate analysis and visual and infrared spectrometry. The behaviour of S-methyldithizone, dithizone, and its known oxidation products towards thin-layer chromatography with a range of solvents is described and the significance of the R F values discussed.

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

Studies of the solvent extraction of cadmium and silver dithizonates

An extensive study was made of the solvent extraction of cadmium and silver dithizonates into chloroform A few extractions of silver dithizonate were made into carbon tetrachloride. In most cases extraction curves of PH versus % metal extracted were obtained and reported in terms of the PH of 50% extraction. The shift of the extraction curves to higher PH values due to the effect of ions in the aqueous phase which complex with the cadmium or silver ions was investigated An equation was developed which would predict the PH of 50% extraction for the extraction from the solutions containing these complexing ions The effects of chloride, bromide and iodide ions on the extraction of cadmium and the effects of chloride, bromide, iodide, thiocyanate and thiosulfate ions on the extraction of silver. Extraction constants for the various extractions were determined.

Effects of temperature and non-aqueous solvent changes on silver dithizonate extractions

The extraction of 10 −7 M silver ion from aqueous solutions into non-aqueous solvents containing dithizone has been investigated. The effects caused by changing the temperature and non-aqueous solvent were studied. Values of the extraction constant for extractions into chloroform and carbon tetrachloride were obtained as a function of temperature. Plots of the logarithm of the constants versus the reciprocal of the absolute temperature were straight lines. A linear relation was found between the extraction constant and the ratio of the solubilities of silver dithizonate and dithizone in the non-aqueous solvent. This relation was found to hold for extractions in which the nonaqueous phase was dichloromethane, chloroform, carbon tetrachloride, benzene and chlorobenzene. Les auteurs ont effectué une étude sur l'extraction de l'argent dans des solvants non-aqueux renfermant de la dithiozone. Ils ont examiné l'influence de la température et de divers solvants. Es wird eine Untersuchung beschrieben über die Extraktion von Silber mit nicht-wässrigen Lösungsmitteln in Gegenwart von Dithiozon und der Einfluss von Temperaturänderungen und anderen Lösungsmittel geprüft.

Effects of temperature and non-aqueous solvent changes on silver dithizonate extractions

Effects of temperature and non-aqueous solvent changes on silver dithizonate extractions

Quantitative Isotopic Exchange Analysis. Determination of Silver with Radioactive Silver Dithizonate

分離容易な,しかもある限定された量の放射性試薬(金属塩)と金属との交換反応後試薬を分離し,その放射能をはかれば比放射能の減少からただちに,他に補助的な化学的定蚤手段を必要とせず,高感度で簡便に微量金属の定量が可能である。例として放射性銀-ジチゾン塩と銀との交換反応について可能性をしらべたが銀錯塩(四塩化炭素溶液)と銀(水溶液)との交換反応はすみやかに平衡に達し,0.1μg程度も交換定量が可能である。強酸酸性や共存物質の影響は受けやすいが,なんらかの妨害がある場合には二重実験によりその補正ができる。