Gowda, H. Sanke

Keshavan, B.

English

NOPR

INDIAN J. CHEM., VOL. 15A, AUGUST 1977bear a linear relationship with the number of carbonatoms. This shows that the additive character ofRM is exhibited by these amino acids. The mecha-nism of separation of amino acids on silica gel-calcium oxalate layer is probably an adsorptionprocess which is influenced mainly by (i) reversiblehydrogen bond formation between the hydrogenatom of the amino group or carboxylic groupand the oxygen atom of the adsorbent (silica geland calcium oxalate), as has been proposed byBark and Graham? for the TLC separation ofphenols on polyamide impregnated layers of CElluloseand (ii) a weak bond formation by the donation oflone pair of electrons by N of NH2 group to thecalcium ion, as suggested by Yasuda" for the TLCseparation of aromatic amines on CdS04 impregnatedsilica gel plates. Besides the above two factors,the extent of adsorption is also influenced by stericand electronic effects of the substituent on theamino acid molecule. Further the possibility ofhydrogen bonding between the N of NH2 and theH of the hydrated silica in the same manner asproposed bv Pires and Roseira" cannot be ruled out.Hence the movement of spots, i.e. RF valuesdepend upon the above adsorption factors and thesolvation factor.ReferenceS1. SRIVASTAV.\,S. P. & DUA,v. K., Z. analyt.cso«, 275(1975), 29.2. SRIVASTAVA,S. P. & DUA,V. K., Z. analyt. Cheni., 276(1975). 382.3. SRIVASTAVA,S. P. & DUA,V. K., Z. analyt. Chem., 279(1976). 367.4. BARK,L. S. & GRAHAM,R. J. T., J. Chromatog., 27 (1967),109.5. YASUDA,K., J. Chromatog., 60 (1971), 144.6. PIRES,L. :\1. & ROSER!.",A.N., J. Chromatog., 56 (1971),59.Chlor'promazine Hydrochloride as aSpectrophotometric Reagent for Os(VIII) &Os(VI)H. SANKEGOWDA& B. KESHAVANDepartment of Postgraduate Studies &Research in Chemistry, University of MysoreManasa Gangotri, Mysore 570006Received 28 September 1976; revised 25 February 1977accepted 6 March 1977Chlorpromazine hydrochloride forms a red colouredspecies with Os(VIII) and Os(VI) in hydrochloric acidrnedium. The red species exhibits absorption maxi-mum at 530 nrri. A twelve-fold molar excess of thereagent is necessary for the full development of colourintensity. The sensitivity of the reaction is 0·015211~/cm2 for Os(VIII) and 0·0134 11~/cm2 for Os(VI).Beer's law is valid over the concentration range0.08-7.2 ppm for Os(VIII) and 0·04-8·6 pprn for Os(VI).The effects of acidity, time, order of addition ofreagents, temperature, rea~ent concentration anddiverse ions are reported.CHLORPRO:.\IAZINE hydrochloride (CPH)was proposed for the spectrophoto~etr!c deter-mination of Pd(II)l. A survey of chemical hterature762showed that no attempt has been made to studythe reaction between CPH and osmium. In thepresent investigation, the reaction of CPH withOs(VIII) and Os(VI) has been studied. On the basisof the results CPH is proposed as a sensitivereagent for the rapid spectrophotometric deter-mination of Os (VIII) and 03(Vl).Standard solution of Os (VIII) was prepared fromosmium tetroxide (Johnson Matthey) in 0·2211sodiumhydroxide. Standard solution of Os(VI) was pre-pared from potassinm osmate (Johnson Matthey)in doubly distilled water. The stock solutions werefurther diluted to give standard solutions containing30 flog/ml of Os(VIII) or Os(VI). A 0'2% aqueoussolution of CPH (May & Baker) was prepared andstored in the refrigerator. Solutions of acids anddiverse ions of suitable concentrations were pre-pared using analytical grade reagents.Procedure for the determination of Os (VIII) orOs(VI) - To an aliquot of the stock solutioncontaining 2 to 180 [Lg of Os(VIII) or 1 to 215 !-kgof Os(VI) were added 12·5 ml of 6J1 hydrochloricacid and 3 ml of 0·2% CPH solution and the volumemade up to 25 ml by adding doubly distilled water.The solution was mixed well and the absorbancewas measured at 530 nm against a reagent blankprepared in the same way. The amount of osmiumwas then deduced from the standard calibrationcurve.CPH is oxidized to red-coloured radical cation2,3by Os (VIII) or 03(VI) instantaneously in hvdro-chloric acid medium at room temperature (27°).Os(IV) docs not react with CPH. The red radicalcation formed in sulphuric acid medium is stablefor only 10 min. Nitric acid medium cannot beused as it slowly oxidizes CPH. Maximum absor-bance is achieved in 2·0-3'5211 hydrochloric acid.The absorbance values remain constant for 1 hr inhydrochloric acid medium. Hence, a hydrochloricacid strength of 3.11 was chosen for all subsequentstudies.The red species exhibit maximum absorbanceat 526-532 nm. The CPH and Os(VIII) or Os (VI)do not absorb around this wavelength. A 12-foldmolar excess of the reagent is required to obtainthe maximum intensity of colour. The absorbancereadings are constant in the temperature range4-50°. No change in the absorbance is observedwhen the order of addition of reactants was changed.Beer'S law is valid over the concentration range0,08-7,2 ppm of Os(VIII) Or 0·04-8·6 ppm of Os(VI).The optimum concentration ranges as evaluatedby Ringborn's method+" are 0·8-7,0 ppm for Os (VIII)and 0·8-8,0 ppm for Os(VI). According to Sandell'sexpression, the sensitivities of the reaction are 0·0152[Lg/cm2 for Os(VIII) and 0·0134 [Lg/cm2 for Os(VI).Sample solutions containing 4 flog/ml of Os (VIII)or Os (VI) prepared by the standard procedure gavea relative error of ± 0'5.%.The following amounts' (flog/ml) of diverse ionswhich commonly accompany Os(VIlI) are foundto give less than ± 2% error in the determinationof 4 flog/ml of osmium: rhodium(III) 14, iridium(III)13, platinumff v) 12, gold(III) 0·5, ruthenium(III)0'4, palladium(II) 0'4, nickel (II) 575, cobalt(II)·80, copper(II) 28, iron (III) 2, chloride 8000, bromide1790, fluoride 1350, nitrate 4625, acetate 4620,'phosphate 1285, EDTA 4350, sulphate 900 and'iodide 8.The method has been successfully utilized for thedetermination of Os(VIII) in synthetic mixturescorresponding to syserkite.The proposed method offers the advantages ofsimplicity, rapidity and sensitivity without the needfor extraction or heating. The sensitivity of theproposed method is found to be more than that ofother spectrophotometric reagents for Os(VIII) like2-mercaptobenzimidazole6, 2-mercaptobenzothiazole7,1-carbamidino-3-methyl-5-pyrazolene8, acenaphthene--quinone monoxime? and rubeanic acid'",.Rete rences1. SANKE GOWDA, H. & KESHAVAN, R, Z. analyt. cu,«,273 (1975), 31-2. DWIVEDI, P. c.. GURUDATH RAO, R., BHAT, S. N. &R.'l.O, C. :--I.R, Spectroctiini. Acta, 31A (1975), 129.3. PIETTE, L. H., BULOW, G. & YA~IAZAKI, I., Biocbim.Biophys. Acta, 88 (1964), 120.4. RINGBOM, A., Anaiyt. Chem., 115 (1938). 332.5. AYREs, G. H., Analyt. cte.«, 21 (1949), 652.·6. BERA, R C. & CHAKRABARTTY, :'1.1. ]\1., Analyt. cu«,38 (1966), 1419.7. BERA, B. C. & CHAKR_~BARTTY, ;\1. 1\1., Microcheni. I,11 (1966), 420.8. PODD_~R, S. N. & ADHYA, J. N., Sci. cuu., 30 (1964),50.9. SINDHWA~I, S. K. & SIl\'GH, R P., Microchem. I, 18(1973), 627 ..10. BHOWAL, S. K, Anal. Chim. Acta, 69 (1974), 465.Rapid Spectrophotometric Determination ofCe(IV). As(III) & Nitrite with PromethazineHydrochlorideH. SANKE GOWD,\ & K. X. THIM~IAIAHIDepartment of Postgraduate StudiesResearch in Chemistry, University of MysoreManasa Gangot ri , Mysore 570006Received 10 September 1976; revised 12 December 1976accepted 2 February 1977Promethazine hydrochloride is proposed as a newreagent for the spectrophotometric determination ofcerium(IV), arsenic(III) and nitrite. The reagentforms red-coloured product with Ce(IV) instantane--ousty in 3·9-5·3M phosphoric acid. The red colourexhibits absorption maxlrnum at 518 nm with molar.absorptivity 1·006 x 10' litre rnole'? crrr", Beer's lawis valid over the concentration range 0·40-15·6 ppm ofCe(IV). Foreign ions which commonly accompanyCe(IV) do not interfere. Arsenic(III) and nitrite areindirectly determined.SANKE GOWDA et aZ.1,2 proposed promethazine. hydrochloride (PH), 10-[2-dimethylaminopropyl]phenothiazine hydrochloride as redox indicator invanadametry- and cerimetry-. The authors havenow investigated the colour reaction between PHand cerium(IV) and proposed PH as a sensitivereagent for the spectrophotometric determinationof Ce(IY), As (III) and nitrite. The proposed methodNOTESoffers the advantages of simplicity, sensitivity andno need for extraction.Stock solutions of cerium(IY) sulphate in 0'5Msulphuric acid, sodium arsenite (prepared fromarsenic trioxide) and sodium nitrite were preparedand standardized by the known methods. A 0'2%solution of PH was prepared in doubly distilledwater and stored in an amber bottle in a refrigerator.Solutions of diverse ions of suitable concentrationswere prepared using analytical grade reagents.Beckman model DB spectrophotometer 'withstoppered silica cells of 1 em optical path was usedfor absorbance measurements.procedure for the determination of Ce(IV) - Analiquot of the stock solution containing 10-390 [J.gof Ce(IV), 11 ml of 10M phosphoric acid and 4 mlof 0·2% PH solution were taken and the solutiondiluted to 25 ml with doubly distilled water. Theabsorbance was measured at 518 nm against acorresponding reagent blank prepared in the samemanner. The amount of cerium was then deducedfrom the standard calibration curve.Procedure for the determination of arsenic(III)-Aliquots of 0·5, 1'0, 1'5, 2·0 ., 6·0 ml ofarsenic(III) solution (3'75-60 [J.g) were taken intwelve 25 ml volumetric flasks. A thirteenth 25ml flask was used for a simultaneous blank deter-mination. 2 ml of 2·5M sulphuric acid, 0·5 ml ofosmium(VIII) (1·2 l..I.g)and 2 ml of O'OOlM eeriesulphate were then added successively to eachflask. After shaking the solution, 11 ml of 10Mphosphoric acid and 4 ml of 0·2% PH solution wereadded and diluted to the mark with doubly distilledwater, shaken thoroughly and the absorbancesmeasured at 518 nm against distilled water. Theamount of arsenic(III) in a test solution was thendeduced from the standard calibration curve con-structed by plotting the concentration of arsenic(III) versus the difference in the absorbance read-ings between the blank (in thirteenth flask) andthe sample.Procedure for the determination Of nitrite - 2 mlof 2M sulphuric acid and 2 ml of 0'001M eerie sul-phate were taken in each of twelve 25 ml volumetricflasks. 4 ml of sodium nitrite solution containing1·25-43 [J.g of nitrite was transferred into eachvolumetric flask. After 5 min , 11 ml of 10Mphosphoric acid and 4 ml of 0'2% PH were addedand the volume made up to the mark with doublydistilled water. A blank containing all the reagentsexcept nitrite was prepared in the thirteenth flask.All the thirteen solutions were shaken thoroughlyand the absorbances measured at 518 nm againstdistilled water. The amount of nitrite in a testsolution was deduced from the standard calibrationcurve constructed as described in the determina-tion of As(III).Cerium(IV) readily oxidizes PH to red colouredspecies in sulphuric or phosphoric acid medium. Themaximum colour development takes place instanta-neously at room temperature (27°) in 3'9-5'3M phos-phoric acid solutions. The red coloured species assum-ed to be a radical cation shows maximum absorption at518 11m and the absorbance remains constant for20 min. The red colour is stable for about 5 min763

Chlorpromazine Hydrochloride as a Spectrophotometric Reagent for Os(VIII) & Os(VI)

http://nopr.niscair.res.in/bitstream/123456789/53181/1/IJCA%2015A%288%29%20762-763.pdf

Chlorpromazine Hydrochloride as a Spectrophotometric Reagent for Os(VIII) & Os(VI)

Abstract

Similar works

Full text

Available Versions

NOPR