Diphenic acid as an analytical reagent

Summary Diphenic acid can separate thorium completely from moderate amounts of ferrous iron and titanium in almost neutral solutions. As the reagent forms quantitative precipitates with ferric iron and zirconium, workable methods for their separation from thorium and their co-determinations in a mixture with the help of this reagent have also been developed. The reagent can separate thorium from zirconium by precipitating the latter below p_h2, and the same from iron(ic) can be accomplished by the use of ascorbic acid as a masking agent. Ferric iron can be precipitated from solution containing ascorbic acid, by the ammonium salt of the reagent. A convenient process for the estimation and separation of zirconium, thorium, iron(ic) and titanium, when present in a mixture, has also been described, which involves the proper control ofph and the use of ascorbic acid as a complexing agent for ferric iron.My sincere thanks are due to Dr. A.K. Mukherjee of the Indian Association for the Cultivation of Science, Calcutta for his valuable suggestions and to Dr. A. K. Ghosal, Principal, Darjeeling Government College for providing laboratory facilities.     

Rapid titrimetric determination of thorium with fluoride using SPADNS

Summary A rapid titrimetric method for the estimation of thorium in the range from 5 to 88 mg. in a 50 ml. of final volume has been developed which involves the adjustment of P_h at 3.0, addition of 2 ml. of 0.02% SPADNS indicator, dilution to volume and titration with standard NaF until the colour obtained matches a blank containing the buffered solution of the indicator alone. The method has been standardised against known amounts of thorium and a calibration curve relating the titre of the fluoride solution to thorium content has been prepared. Interferences of various cations and anions have also been studied. From the results, the quantitative nature of zirconium interference has been confirmed. The method for the determination of thorium is very rapid and the colour change being sharp from blue-violet to scarlet-red, the detection of endpoint is not at all difficult.The author wishes to thank Dr. A. K. Ghosal, Principal, Darjeeling Government College, for providing Laboratory facilities and Prof. P. Ray and Dr. A. K. Mukherjee of the Indian Association for the Cultivation of Science, Calcutta for their encouragement in the research work.     

Organic azo-dyes in quantitative analysis

Summary Chrom red brown 5RD was used as an indicator for complexometric titration of thorium. The change in the colour at the end-point was from wine-red to yellow. It is recommended that the thorium buffered aliquot should not contain less then 200 g thorium per 10 ml for a precise estimation. A range of p_H from 2.5 to 3.5 has been found satisfactory for such a titration. Ferri, ferro and zirconium ions interfere; they should be separated beforehand.Part I: Zaki, M. R., and K. Shakir: Z. analyt. Chem. 174, 274 (1960).     

Analytical aspects of some organic acids

Summary Back titrimetric procedures for the estimation of aluminium, zirconium, and thorium have been developed, which involved the adjustment of the concentration of the metallic salts, concentration of EDTA,ph, and temperature, addition of indicator solution (namely, 2-hydroxy3-naphthoic acid and back titration with standard 0.1 M ferric chloride solution. This method is based on the fact that the excess EDTA, which is added to the metal solutions may be back titrated with iron(III), which forms a highly coloured complex with the indicator, when present in slight excess. Quantities of aluminium, zirconium and thorium as small as 10.8, 4.6, 11.6 mg respectively, can be back titrated with in experimental error, when present in a volume of 100 ml.Part IV: See Z. analyt. Chem. 172, 356 (1960).     

Use of organic reagents in inorganic analysis

Summary Seven anilic acids obtained from phthalic anhydride and aromatic amines were studied for their quantitative precipitating action on zirconium. The anilic acids from p-toluidine, m- and p-nitranilines and -naphthylamine were only found effective for the quantitative determination of zirconium. Zirconium is completely precipitated at a little lowerph value with these reagents, than thorium. Compositions of the zirconium salts of these acids are not definite, so ignition of the precipitates to zirconia is necessary. Separation of zirconium from common elements like Cu, Al, Cr, Mg, Zn, Ti etc. may be done with ease. But for iron, uranium, cobalt and nickel double precipitation is essential. A considerable amount of thorium has been separated from zirconium, by extraction with amylacetate.     

Direct complexometric titration of thorium with versene using SPADNS

Summary The existing volumetric methods for the determination of thorium are indirect and unsatisfactory. A direct titrimetric method for the estimation of thorium has been developed which involves the adjustment ofph, addition of 1 ml. of 0.02% SPADNS indicator, dilution to volume and titration with versene. It is based on the fact that thorium forms a coloured complex with SPADNS and after the bulk of thorium has reacted with versene, the highly coloured thorium- indicator complex is destroyed, marking the end point. Quantity of thorium as small as 5 mg. can be titrated accurately when present in a volume of 50 ml. Determination of thorium can also be made in presence of large amount of iron by adding ascorbic acid prior to the titration. Interferences of various ions have also been studied. The method proposed for thorium is selective and should be of considerable use in many cases.The author's thanks are due to Dr. A. K. Ghosal, Principal Darjeeling Government College, for providing all laboratory facilities and Dr. A. K. Mukherjee, Indian Association for the Cultivation of Science, Calcutta for his kind help in the work.     

Gravimetric determination of thorium and zirconium

Summary Thorium and zirconium can be quantitatively precipitated by quinaldinic acid atph 2.7 and 3, respectively. As the precipitates are of nonstoichiometric composition they are to be ignited to oxides. By this reagent thorium can be quantitatively separated from arsenic (As³⁺), mercury (Hg²⁺), rare earths, manganese, magnesium and alkaline earths and zirconium from all the aforesaid ions excepting rare earths which contaminate to a slight extent.     

Conductometric estimation of thorium in dilute thorium chloride

Summary Conductometric titrations of thorium chloride against oxalic acid, ammonium oxalate and silver nitrate have been carried out at high dilutions (0.001, 0.0005 and 0.00033 M) of the chloride. Oxalic acid is found to be a suitable titrant for rapid estimation of thorium, the minimum error being +0.5%. The other titrants do not give good results. The titrations with ammonium oxalate indicate the step-wise ionisation of ThCl₄ into ThCl₂ ²⁺, ThCl³⁺ and Th⁴⁺. For mixtures of thorium chloride and cerous chloride, only the equivalence point corresponding to complete precipitation of both thorium and cerium is indicated.The authors express their sincere thanks to Prof. S. S.Joshi for his keen interest in this work and to Dr. G. S.Deshmukh for his advice and help in so many ways during the progress of these studies.     

Organic azo-dyes in quantitative analysis

Summary Chrom Red Brown 5 RD has been found as a sensitive reagent for the spectrophotometric determination of thorium. Concentrations as low as 1 g thorium/1 ml can be easily determined at wave length 485 nm. Sulphate, chloride, ferric and zirconium ions badly interfere, while Li, Na, K, Ni, Co, Cu²+, Cd, Ca, Mg and Cr³⁺ do not. U⁶⁺ and Ce⁴⁺ are permissible as traces.Part II: Zaki, M. R., and K. Shakir: Z. analyt. Chem. 177, 196 (1960).     

Analytical aspects of some azo dyes from chromotropic acid

Summary Nitroso-SNADNS-4, itself a yellow coloured dye in acid medium forms a reddish-pink colouration with thorium in weakly acid solution. The colour is stable for about 24 hours and to a temperature up to 50C. The thorium complex shows maximum absorbance at the wave length 520 m, while that of the dye occurs at 430 m. The maximum intensity of colour of the thorium complex is shown at aph 2.5. The colour system conforms to Beer's law in a wide range of concentration of thorium and presents a reliable method for the spectrophotometric determination of the metal even in presence of a large number of common ions, the ions interfering are: tin, iron, nickel, cobalt, cerium(IV), zirconium, gold, phosphate and fluoride. The average percentage of deviation of the absorbance index in the determination of thorium is 1.14.Part VI: See Z. analyt. Chem. 167, 105 (1959)     

Separations involving sulphides

Summary It has been shown that it is possible to separate and estimate quantitatively platinum, rhenium, gold or pentavalent antimony from zirconium by decomposing the thiosalts, formed by these elements with 2 N sodium sulphide reagent, with hydrochloric acid.Part I: Salaria, G. B. S.: Z. analyt. Chem. 179, 91 (1961).     

Diphenic acid as an analytical reagent

Summary Diphenic acid behaves as a selective reagent for the estimation of thorium in presence of phosphate, arsenate, molybdate, alkaline, earths, copper, cadmium, lead, bismuth, tin, aluminium, chromium, nickel, cobalt, zinc, manganese, magnesium and palladium. Thorium can be successfully separated from the cerite earths by the reagent from solutions having thoria: earth oxide ratio 126 by single precipitation and by double precipitation when the above ratio is 144. The reagent can separate thorium from solutions having ThO₂U₃O₈ ratio upto 180 by double precipitation. The metal can also be recovered from monazite sands.Thanks are expressed hereby to Dr. A. K. Ghosal, Principal, Darjeeling Government College and Dr. A. K. Mukherjee of Indian Association for the Cultivation of Science, Calcutta, for their kind encouragement and to the Government of India, Ministry of Natural Resources and Scientific Research for a gift of Indian Monazite for analysis.     

Analytical aspects of some azo dyes from chromotropic acid

Summary Complexometric titration of thorium with di-sodium versenate solution has been carried out using three dyes: SNADNS, di-SNADNS and nitroso-SNADNS obtained from chromotropic acid. Determinations are suitable with these dyes in the p_H range from 2 to 3, the colour changes at the end point are very distinct with nitroso-SNADNS and di-SNADNS while the colour change with SNADNS at the end point is very difficult to detect. Study of interferences revealed that quite a number of elements like, lead, zinc, mercury, cobalt, nickel etc. do not interfere, whereas heavy interference is caused by iron, zirconium, copper, gold and alkaline earths, Thorium may be separated from them by precipitating it with phthalanilic acid obtained from o-anisidine and the thorium salt on breaking with acid may be determined by versene by the same method. This titrimetric method is expected to become more accurate if the final measurement at the end point is made spectrophotometrically rather than visually.     

Analytical aspects of some organic acids Part III

Summary m-Phenylenedioxydiacetic acid gives a white precipitate with thorium even in the absence of an electrolyte which is quantitative up toph 4. Be²⁺, Mg²⁺, Ca²⁺, Zn²⁺, Pb²⁺ and Mn²⁺ ions are removed by single precipitation and Al³⁺, UO₂ ²⁺ and trivalent cerite earth ions are removed by double precipitation. Sn²⁺, Sn⁴⁺ and Cr³⁺ ions interfere.Part II: See. Z. analyt. Chem.165, 343 (1959).     

Synergistic effect of neutral donors on the extraction of zirconium(IV) by salicylaldoxime in dichloromethane

Liquid-liquid extraction of zirconium(IV) was investigated from dilute hydrochloric acid medium by salicyaldoxime (HA) in dichloromethane. The metal was spiked with ⁹⁵Zr and analyzed by its radioactivity. The effects of different donors, like trioctyl phosphine oxide (TOPO), triphenyl phosphine oxide (TPPO), tributyl phosphine oxide (TBPO), tributyl phosphate (TBP), trioctyl amine (TOA) and Amberlite LA-2 were studied. The adduct formation constants for both binary species (metal-ligand) and ternary species (metal-ligand-donor) were also calculated form the distribution data.One of the authors (S.B.) thanks The University of Burdwan for providing senior research fellowship to her. She also wishes to thank Dr. D. Mukherjee and Dr. S. Bhattacharya, B.U. for their valuable suggestions.     

Reversed Phase Extraction Chromatographic Separation Of Scandium With Amberlite LA-1 From Malonate Solutions

Abstract

Scandium was extracted at pH 5.0 from 0.01 M malonic acid on silica gel column impregnated with Amberlite LA-1. Nickel, zinc, cadmium, mercury, lead, tin, aluminium, and lanthanum in binary mixtures because they could not form malonato complexes. It was separated by the process of selective elution from elements such as zirconium, thorium, uranium, iron(III), gallium, indium, cerium(III), litanium by exploiting difference in stability of malonato complexes. Scandium was separated from multicomponent mixture containing yttrium, titanium, zironium, thorium, uranium and aluminium by a process of selective sorbtion and selective elution.     

Iron,copper and their proteins in substantia nigra of human brain during aging

Liquid-liquid extraction of zirconium(IV) was investigated from dilute hydrochloric acid medium by salicyaldoxime (HA) in dichloromethane. The metal was spiked with ⁹⁵Zr and analyzed by its radioactivity. The effects of different donors, like trioctyl phosphine oxide (TOPO), triphenyl phosphine oxide (TPPO), tributyl phosphine oxide (TBPO), tributyl phosphate (TBP), trioctyl amine (TOA) and Amberlite LA-2 were studied. The adduct formation constants for both binary species (metal-ligand) and ternary species (metal-ligand-donor) were also calculated form the distribution data.One of the authors (S.B.) thanks The University of Burdwan for providing senior research fellowship to her. She also wishes to thank Dr. D. Mukherjee and Dr. S. Bhattacharya, B.U. for their valuable suggestions.     

Gas-chromatographische Trennung und Bestimmung von Aminos?uren

Ohne ZusammenfassungHerrn Prof. Dr. Dr. E. Strack in Verehrung zum 65. Geburtstag gewidmet.I. Mitteilung: Wagner, J., u. G. Winkler: diese Z. 183, 1 (1961).