Gowda, H. Sanke

Ramappa, P. G.

English

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Efforts to increase the tolerance limit of cations bythe addition of masking agents were unsuccessful.The continuous variation! and slope ratio"methods failed to reveal any definite compositionfor Ru(III)-PH complex owing to the masking ofyellow colour of ruthenium at relatively low rangeof reagent concentration. However, the molar ratiomethod' shows a sharp break at the ruthenium toreagent ratio of 1: 2 in the presence of HCI orH2SO,. The apparent stability constant (log K) ofthe complex in 3M HCI and in 1·5M H2S04 at27° ± 1°C as evaluated by molar ratio method' is10'02±0'1 and 10·65±0·1 respectively.References1. SANKE GOWDA, H. & KESHAVAN, B., Indian J. Chem.,14 (1976), 293.2. BEAMISH, F. E., The analytical chemistry of the noble metals(Pergamon Press, London), 1966, 250.3. RINGBOM, A., Z. analyt, Chem., 115 (1938). 332.4. AYRES, G. H., Analyt. Chem., 21 (1949), 652.5. JOB, P., Ann. Chim., 9 (1928), 113.6. HARVEY, A. E. & MANNING, D. L., J. Am. chem . Soc., 72(1950), 4488.7. YOE, j. H. & JONES, A. L., Ind. Engng Chem., 16 (1944),111.Spectrophotometric Determination of Ru(III)with Trifluoperazine DihydrochlorideH. SANKE GOWDA & P. G. RAMAPPAPostgraduate Department of Chemistry, University of MysoreMysoreReceived 6 October 1975; accepted 11 December 1975A spectrophotometric method has been devised forthe determination of microgram amounts of Ru(III)utilizing the reaction between trifluoperazine dihydro-chloride and ruthenium(III) in strong sulphuric orhydrochloric acid. The orange-red complex hasabsorption maximum at 500 nm with molar absorpti-vity 4·285 x 103 litre mole= em>, The sensitivity is0·0233 I1g Ru cm! for log 1011=0.001. Beer's law isvalid over the concentration range 1·0-8·8 I1grutheniumml-l and the optimum range for the effective spectro-photometric determination is 2·0-8·0 I1gRu ml-l• Thecomposition of the complex is 1: 1. The influence ofsome common ions is reported.A WIDE variety of chromogenic reagents em-ployed for the spectrophotometric determinationof Ru(III) have been reviewedv+, Unfortunately,the formation of the complexes between rutheniumand the chromogenic reagents is quite slow inaqueous media at room temperature, and conditionsfor obtaining reproducible colour development areusually quite empirical, i.e. heating for a specifictime at a specific temperature is required.During the investigation+ on the spectrophoto-metric determination of Pd(II) with trifluoperazinedihydrochloride (TFP) , the latter was found to givean orange-red colour with Ru(III) instantaneouslyin the presence of sulphuric or hydrochloric acid.This has now been made the basis of a spectro-photometric method for the determination of micro-gram amounts of Ru(III). The proposed methodoffers the advantages of simplicity, reasonableNOTESsensitivity, insensitivity to temperature and rapiddetermination in higher acid concentration withoutthe need for extraction or heating.A stock solution of ruthenium was prepared bydissolving 0·9924 g of Ru(III) chloride (Mis JohnsonMatthey, London) in 500 ml of 1M hydrochloricacid and standardized gravimetrically by precipitat-ing ruthenium as the hydrated oxide, followed bycareful ignition in air and then reducing in hydrogenand cooling in an atmosphere of carbon dioxide.A stock solution of TFP (Smith, Kline & French)was prepared by dissolving O·50 g of TFP in 250 mlof doubly distilled water. This was stored in anamber-coloured bottle in a refrigerator.All other reagents were of analytical grade andwere used without further purification.Determination of Ru(III) - To a sample solutioncontaining 25-220 ILgof Ru(III) was added sulphuricacid so that the final solution was 1·5M in sulphuricacid. 5 ml of 0·2% TFP was added and the solu-tion diluted to 25 ml by adding doubly distilledwater. The solution was mixed thoroughly andthe absorbance measured at 500 nm against acorresponding reagent blank. The Ru(III) concen-tration of the sample solution was then deducedfrom the standard calibration curve.A detailed investigation of Ru-TFP complex hasshown that TFP forms an orange-red colouredcomplex instantaneously in the presence of sulphuricor hydrochloric acid (PH 0·0-3'5). The maximumcolour development takes place at room temperatureand requires no heating. The sensitivity of thereaction and the stability of the orange-red complexdepend on the nature and strength of the acidmedium. The sensitivity in four acid media is inthe order of HCl>H2SO,>HsPO,>AcOH. Themaximum colour development takes place imme-diately in hydrochloric or sulphuric acid medium andafter 10 min in phosphoric or acetic acid mediumafter mixing the reagents. The orange-red complexis stable in 1·5M H2S04, HCI, AcOH and HsPO, for40, 15, 10 and 5 min respectively. Hence thesulphuric acid medium has been selected. Nitricacid medium cannot be used as it oxidizes TFP to ared-coloured radical.The absorbance of the complex remains constantin 0·2-2·0M H2S04, At higher acid concentrations(>3·0M) the reagent slowly undergoes oxidationto a red- coloured radical.It was found that a nineteen-fold molar excess ofthe reagent was necessary in order to assure com-plete complexation. The orange-red complex exhi-bits absorption maximum at 500 nm at which pointthe reagent does not absorb. The absorbancevalues remained constant for 40 min and wereinsensitive to temperature in the range 5-60°C.The order of addition of reagents was not critical.Beer's law was obeyed in the concentration range1·0-8·8 (log Ru(III) ml'". The optimum concentra-tion range evaluated by Ringbom methodt-" was2·0-8·0 flg Ru(III) ml+, The molar absorptivity is4·285 X 103 litre mole+ em+ and the Sandell sensiti-vity index is 0·0233 p.g Ru(III) crrr".Composition and nature of , the complex - Thecomposition of the complex was studied by Job'smethod9,lo of continuous variation using equimolar631INDIAN J. CHEM., VOL. 14A, AUGUST 1976TABLE 1 - DETERMINATIONOF RUTHENIUMIN SYNTHETICMIXTURESCORRESPONDINGTOURANIUMALLOY(FUEL)Ru(III) U Mo Zr Pd Rh Ru(III)present ppm ppm ppm ppm ppm foundppm ppm0·40 19 0'5 0·02 0·01 0·01 0'400·80 38 1'0 0·04 0'02 0·02 0·801'20 57 1·5 0·06 0·03 0·03 1-191-60 76 2·0 0·08 0·04 0·04 1·542·00 95 2·5 0'10 0·05 0·05 1·89TABLE2 - DETERMINATIONOFRUTHENIUMIN Zn-Mg ALLOY(Av. of 5 determinations)Zinc Magnesium Ru(III) (\Lg)added addedmg mg Added Found30 4·00 4·0030 4·00 4·0015 15 4'00 3'9915 15 2'00 2·00solutions and mole ratio method-', Both themethods indicate the formation of 1: 1 complexbetween the metal and the reagent. The orange-redsolution of Ru-TFP was passed through Dowex50W-X8 cation exchange resin and Dowex 1-~8anion exchange resin. The orange-red solutionpassed through the anion exchange resin but theorange-red colour was retained on the cation ex-change resin. This indicated that the complex wascationic.Effect of diverse ions - The following amounts(flogmr") of foreign ions were found to give lessthan 3% error in the determination of 4 flogofRu ml'<: U02(I1) 800; Ni(I1) 1600; Cu(I1) 300;ce(II) 100; Fe(III) 8; Pt(IV) 6; Rh(I1I) 6; Os(VIII)4; Zn(I1) 1000; Mg(I1) 1000; Zr(IV) 10~; Mo(VI)50; chloride 2000; fluoride 2000; bromIde ~OOO;iodide 25; sulphate 2000; acetate 2000; nitrate.800; EDTA 1200. Thiosulphate, thiourea, Pd(II) ,Au(I1I), Ag(l), V(V) and Ce(IV) were found tointerfere at all concentrations.Analysis of synthetic samples - Fuel for the initial-core loading of the Experimental Breeder Reactor-II(EBR-II) is an alloy of 95% uranium, 2'5% molyb-denum, 2·0% ruthenium and smaller amounts ofzirconium, palladium and rhodium. In one phaseof the processing system devised for EBR-I1, moltenzinc and zinc-magnesium alloy are used as. solventsin the separation of uranium from rtrthenium andother fission products. Hence the analysis of ura-nium fuel and zinc-magnesium alloy is of greatimportance. Synthetic mixtures containing themetals corresponding to (1) the uranium alloy (fuel).and (2) zinc-magnesium alloy were prepared andruthenium content was determined. The results ofanalyses of synthetic mixtures are given in Tables 1and 2.References1. BEAMISH,F. E. & VANLOON,J. C., Recent advances in theanalytical chemistry oj the noble metals (Pergamon Press,Oxford), 1972, 306.-6322. BEAMISH,F. E., Analytical chemistry oj the noble metals(Pergamon Press, Oxford), 1966, 366.3. BOLTZ,D. F. & MELLON,M. G., Analyt, Chem., 46 (1974),234R; 44 (1972), 3OOR; 42 (1970), 152R; 40 (1968),255R; 38 (1966), 317R.4. BEAMISH,F. E. & McBRYDE, W. A. E., Analyt. chim.Acta, 9 (1953), 349; 18 (1958), 551.5. BEAMISH,F. E., Talanta, 12 (1965), 789.6. SANKEGOWDA,H. & RAMAPPA,P. G., J. Indian chem.Soc., 52 (1975), 1123.7. RINGBOM,A., Z. analyt. Chem., 115 (1938), 332.8. AYRES,G. R., Analyt. Chem., 21 (1949), 652.9. JOB, P., Ann. Chim., 9 (1928), 113.10. IRVING,H. & PIERCE, T. B., J. chem, Soc., (1959), 2565.11. YOE, J. H. & JONES,A. L., Ind. Engng Chem., 16 (1944),111.N-Substituted Phenothiazines as Reagents forthe Spectrophotometric Determination ofTraces of Au(III)H. SANKEGOWDA& K. N. THIMMAIAHPostgraduate Department of Chemistry, University of MysoreMysoreReceived 5 November 1975; accepted 26 December 1975Trifiupromazine hydrochloride, promethazine hydro-chloride and mepazine hydrochloride form colouredcompounds with gold(III) in hydrochloric acid medium.Absorption maxima and molar absorptivities of thesecoloured compounds are: for trifiupromazine hydro-chloride 503 om, 1·303 x 10'; for promethazine hydro-chloride 517 nm, 1·609 x 10'; and for mepazine hydro-chloride 514 om, 2·184 x 104 litre mole= cm", The firsttwo N -substituted phenothiazines give full developmentof colour intensity in hydrochloric acid media rangingfrom 2·0-4·0M and 2·5-4·0M respectively and the thirdone in an aqueous solution in the pH range 1·8-2·1.Beer's law is valid over the concentration range 0·32.14·22 ppm of Au for triftupromazine hydrochloride,0·20-11·90 ppm of Au for promethazine hydrochlorideand 0·24-12·64 ppm of Au for mepazine hydrochloride.SANKE GOWDA et al.1 proposed promethazinehydrochloride (PH) as redox indicator forvanadametry, Cavatorta- used the reaction ofPH with palladous chloride for the colorim~tricdetermination of PH. The present paper descnbestriflupromazine hydrochloride (TPH) , PH .a,ndmepazine hydrochloride (MH) as new sensitivereagents for the spectrophotometric determinationof Au(III).A stock solution of gold was prepared from Au(I1I)chloride (Baird & Tatlock, London) in. doublydistilled water and standardized gravimetrically''.Aqueous 0·2% solutions of TPH, PH and MHwere prepared and stored in amber-coloured bottlesin a refrigerator. .Solutions of diverse ions of suitable concentrationswere prepared using analytical grade reagents. .Procedure for the determination of Au(III): WtthTPH - To an aliquot of gold solution containing8,0-355·0 flogwere added 7·5 mlof 10M hydrochloricacid and 3 ml of 0·2% TPH. The solution .wasdiluted to 25 ml with doubly distilled water, mIxedthoroughly and the absorbance measured at 503nm against a corresponding reagent blank prepared

Spectrophotometric Determination of Ru(III) with Trifluoperazine Dihydrochloride

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Spectrophotometric Determination of Ru(III) with Trifluoperazine Dihydrochloride

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