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THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICAL SOCIETYEDITORAL ADVISORY BOARD*Chairman: H. J. Cluley (Wembley)"L. S. Bark (Salford)R. Belcher (Birmingham)L. J. Bellamy, C.B.E. (Waltham Abbey)L. S. Birks (U.S.A.)E. Bishop (Exeter)L. R. P. Butler (South Africa)E. A. M. F. Dahmen (The Netherlands)A. C. Docherty (Billingham)D. Dyrssen (Sweden)J. Hoste (Belgium)H. M. N. H. Irving (Leeds)H. Kaiser (Germany)M. T. Kelley (U.S.A.)W. Kemula (Poland)"W. T. Elwell (Birmingham)"J. A. Hunter (€dinburgh)"G. F. Kirkbright (London)G. W. C. Milner (Harwell)G. H. Morrison (U.S.A.)"J. M. Ottaway (Glasgow)* G . E. Pen ket h (Billingham)"T. B. Pierce (Harwell)E. Pungor (Hungary)D. I. Rees (London)"R. Sawyer (London)P. H. Scholes (Sheffield)"W. H.C. Shaw (Greenford)S. Siggia (U.S.A.)A. A. Smales, O.B.E. (Harwell)A. Walsh (Australia)T. S. West (Aberdeen)A. L. Wilson (Medmenham)P. Zuman (U.S.A.)"A. Townshend (Birmingham)"Members of the Board serving on The Analyst Publications CommitteeR EG I0 N AL ADVl SO RY ED IT0 R SDr. J . Aggett, Department of Chemistry, University of Auckland, Private Bag, Aucltland, NEWProfessor G. Ghersini, Laboratori CISE, Casella Postale 3986, 201 00 Milano, ITALY.Professor L. Gierst, Universit6 Libre de Bruxelles, Facult6 des Sciences, Avenue F.- D. Roosevelt 50,Professor R . Herrmann, Abteilung fur Med. Physik., 63 Giessen, Schlangenzahl 29, GERMANY.Professor W. E. A. McBryde, Dean of Faculty of Science, University of Waterloo,Waterloo, Ontario,Dr. W.Wayne Meinke, KMS Fusion Inc., 3941 Research Park Drive, P.O. Box 1567, Ann Arbor,Dr. 1. Rubeska, Geological Survey of Czechoslovakia, Kostelni 26, Praha 7, CZECHOSLOVAKIA.Dr. J . RGiEka. Chemistry Department A, Technical University of Denmark, 2800 Lyngby, DENMARK.Professor K. Saito, Department of Chemistry, Tohoku University, Sendai, JAPAN.Dr. A. Strasheim, National Physical Research Laboratory, P.O. Box 395, Pretoria, SOUTH AFRICA.ZEALAND.Bruxelles, BELGIUM.CANADA.Mich. 481 06, U.S.A.Published by The Chemical SocietyEditorial: The Director of Publications, The Chemical Society, Burlington House,London, W1 V OBN. Telephone 01 -734 9864. Telex No. 268001.Advertisements: J. Arthur Cook, 9 Lloyd Square, London, WC1 X 9BA. Telephone 01 -837 631 5.Subscriptions (non-members): The Chemical Society Publications Sales Office, Blackhorse Road,Letchworth, Herts., SG6 1 HN.Volume 101 No 1204@ The Chemical Society 1976July 197

ISSN:0003-2654    

DOI:10.1039/AN97601FX025

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年代:1976

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ANALAO 101 (1 204) 497-592 (1 976)ISSN 0003-2654July 1976THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICAL SOCIETYCONTENTSREVIEW PAPERProperties and Uses o f the Colorimetric Reagents 2-Nitroso-5-dimethylaminophenoland 2-Nitroso-5-diethylaminophenol f o r Cobalt-Kyoji TBei and Shoji MotomizuORIGINAL PAPERS497512 Analysis o f Steroids. Part XXVII. Difference Spectrophotometric Determination o fOestrogens in Oily Injections in the Presence o f 4-Ene-3-ketosteroids-S6ndor GOrO6516 Determination o f Aluminium in Iron Ore and Iron Ore Sinter by a ComplexometricMethod-Samaresh Banerjee and R. K. Dutta51 9 Spectrophotometric Studies on the Determination o f 2.6-Dichlorophenol-J. LiptBk,J. Reiter and L. Toldy522 Colorimetric Determination o f Aniline in the Presence o f 4-Aminophenol and OtherOxidation Products-Josef Chrastil528 Spectrophotometric Determination o f Parathion and Paraoxon Using Alkaline Hydroxyl-amine for the Liberation o f 4-Nitrophenol-N.Ramakrishna and B. V. Ramachandran533 Ultraviolet Spectrophotometric and Thin-layer Chromatographic Determination ofPirimiphos-ethyl and Pirimiphos-methyl in Insecticide Formulations-S. H. Yuen540 Thin-layer Chromatographic Analysis of Some Triphenodioxazines (1,4-Benzoxazino-[2,3-b]phenoxazines)-S. K. Jain and R. R. Gupta543 Re-examination o f the Microanalysis o f Non-ionic Surfactants t h a t Contain Polyoxy-ethylene Chains by the Method Involving Solvent Extraction o f the Thiocyanato-cobaltate(l1) Complex-Akio Nozawa, Toshio Ohnuma and Tatsuya Sekine549 Rapid and Precise Determination of Nitroglycerin by the Schultze - Tiemann Method-Abdel Fattah Dawoud, A.Abdel Wahid and A. El-Damaty553 Analytical Optoacoustic Spectrometry. Part II. Ultraviolet and Visible OptoacousticSpectra o f Some Inorganic, Biochemical and Phytochemical Samples-M. J. Adams,B. C. Beadle, A. A. King and G. F. KirkbrightDetermination of Saccharin i n Soft Drinks by Molecular Emission Cavity Analysis-R. Belcher, S. L. Bogdanski, R. A. Sheikh and Alan TownshendDetection and Determination of Polynuclear Aromatic Hydrocarbons by LuminescenceSpectrometry Utilising the Shpol'skii Effect a t 77 K. Part 111. LuminescenceExcitation Spectra-R. Farooq and G. F. KirkbrightSimultaneous Extraction and Concentration of Cadmium and Zinc from Soil Extracts-A. H. C. Roberts, M. A. Turner and J. K. SyersVariation i n Ambient Temperature as a Source of Error i n Absorbance MeasurementsMade w i t h Single-beam Spectrophotometers-Paul J. Milham and Colin C. ShortCO M M U N ICATIO N S562566574579582 lonisation Interferences i n Carbon Furnace Atomic-absorption and Atomic-emissionSpectrometry-J. M. Ottaway and F. Shaw585 A Computerised Programmable Monochromator for Flexible Multi-element Analysisw i t h Special Reference t o the Inductively Coupled Plasma-P. W. J. M. Boumans,G. H. van Goo1 and J. A. J. Jansen587 Electrothermal Atomisers as Resonance Detectors-J. B. Dawson, E. Grassam andD. J. Ellis589 Book ReviewsSummaries of Papers in this Issue-Pages iv, v. vii x, xii, x i i iPrinted by Heffers Printers Ltd, Cambridge, EnglandEntered as Second Class a t New York, USA, Post Offic

ISSN:0003-2654    

DOI:10.1039/AN97601BX027

出版商:RSC    

年代:1976

数据来源: RSC

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iv SUMMARIES OF PAPERS I N THIS ISSUE July, I 9 76Summaries of Papers in this issueProperties and Uses of the Colorimetric Reagents2-Nitroso-5- dimethylaminophenol and 2-Nitroso-5-diethylaminophenolfor CobaltA ReviewSummary of ContentsIntroductionNitrosophenol and nitrosonaphthol derivativesSynthesis of nitroso-DMAP and nitroso-DEAPProperties of nitroso-DMAP and nitroso-DEAPCobalt complexes of nitroso-DMAP and nitroso-DEAPDetermination of cobalt with nitroso-DMAP and nitroso-DEAI’Determination of cobalt in pure nickel saltsSpectrophotometric determination in aqueous solutionSpectrophotometric determination by solvent extractionSpectrophotometric determination in aqueous solutionSpectrophotometric determination by solvent extractionDetermination of cobalt in iron and steelSpectrophotometric determination of trace amounts of cobalt in pure reagentchemicalsPreparation of sample solutionDetermination of cobaltDetermination of cobalt in sea water with nitroso-DEAPDetermination of cobalt in uranium oxide (U,O,), pure uranium and a uranylsaltPreparation of sample solutionProcedure I, for samples containing more than 5 p.p.m.of cobaltProcedure 11, for samples containing 0.5-5 p.p.m. of cobaltProcedure 111, for samples containing 0.01-0.5 p.p.m. of cobaltDetermination of cobaltConclusionReprints of this Review paper can be obtained from The Chemical Society,Publications Sales Officer, Blackhorse Road, Letchworth, Herts., SG6 lHN, a tk l per copy (with a 25 per cent. discount for six or more copies), post free.A remittance for the correct amount, made out to The Chemical Society,should accompany every order; these reprints are not available throughTrade Agents.KYOJI TOE1 and SHOJI MOTOMIZUDepartment of Chemistry, Faculty of Science, Okayama University, Tsushinia,Okayama-shi, Japan.Awalyst, 1976, 101, 497-511.Analysis of SteroidsOestrogens in Oily Injections in the Presence of 4-Ene-3-ketosteroidsA difference spectrophotometric method is described for the determinationof 2.5-5 mg ml-l amounts of oestrogens (esters of oestrone and oestradiol)in oily injections in the presence of a large excess of 4-ene-3-ketosteroids.The method is based on a bathochromic shift of the ultraviolet spectrum ofthe extracts of the samples in methanol in alkaline media.Any interferencecaused by co-extracted oil or by unsaturated ketosteroids is eliminated bycareful choice of pH settings (9.2 for the reference solution by using boratebuffer and the test solution 0.2 N in sodium hydroxide) and reduction withsodium borohydride, respectively. The difference between the results foundand the label claims for four formulations was less than 2% and the relativestandard deviations ranged between 1.1 and 1.7 yo.Chemical Works, Gedeon Richter Ltd., Gyoniroi u t 21, H-1475 Budapest, Hungary.Analyst, 1976, 101, 512-515.Part XXVII. Difference Spectrophotometric Determination ofs. GOROJuly, 1976 SUMMARIES OF PAPERS I N THIS ISSUEDetermination of Aluminium in Iron Ore and Iron Ore Sinterby a Complexometric MethodA complexometric method for the determination of aluminium in iron oreand sinter products has been developed.Iron, manganese, vanadium, etc.,are complexed with mercaptoacetic acid, and aluminium and other elementssuch as titanium, if present, are precipitated as R,O, with hexamethylene-tetramine (hexamine). The precipitate of R,O, is dissolved in hydrochloricacid and complexed with EDTA. The excess of EDTA is titrated withstandard lead solution using xylenol orange as indicator. The EDTA boundto the aluminium is released by boiling with ammonium fluoride and back-titrated with standard lead solution with xylenol orange as indicator andhexamine buffer. The method eliminates the usual solvent extraction pro-cedure and aluminium is separated from iron, manganese, vanadium, calciumand magnesium, etc., in a single step; it takes about 1-2 h and is suitable forroutine analysis.SAMARESH BANERJEE and R.K. DUTTAResearch and Control Laboratory, Durgapur Steel Plant, Durgapur-3, West Bengal,India.Analyst, 1976, 101, 516-518.Spectrophotometric Studies on the Determination of2,6 - DichlorophenolSimple, rapid and quantitative analytical methods are described for thedetermination of 2,6-dichlorophenol in instances when an ether of the samephenol is present in the sample by using near-infrared and ultraviolet spectro-photometry. The mechanism of a generally valid N-alkylating reaction wasestablished in kinetic studies by determination of the 2,6-dichlorophenolproduced by the reaction.J. LIPTAK, J.REITER and L. TOLDYResearch Institute for Pharmaceutical Chemistry, P.O. Box 82, Budapest 1325,Hungary.Analyst, 1976, 101, 519-521.Colorimetric Determination of Aniline in the Presence of4-Aminophenol and Other Oxidation ProductsThe extraction of aniline, followed by coupling it with 8-amino- l-naphthol-3,6-disulphonic acid, and the extraction of 4-aminophenol, followed by allowingits reaction with 1,2-naphthoquinone-4-sulphonic acid, were used for theseparation and determination of aniline and 4-aminophenol in admixture.This method facilitates the fast, accurate and specific determination of bothcomponents independently. It is suitable for the analysis of biochemicalor industrial mixtures containing coloured oxidation products, dyes, plastics,etc.JOSEF CHRASTILDepartments of Pharmacology and Pediatrics, Vanderbilt University School ofMedicine, Nashville, Tennessee 37232, USA.Analyst, 1976, 101, 522-527.Vi THE ANALYST July, 1976Reprints of Review PapersReprints of the following Review Papers published in The Analyst since 1967 are available fromthe Publications Sales Officer, The Chemical Society, Blackhorse Road, Letchworth, Herts., SG61HN (not through Trade Agents).The price per reprint is L1; orders for six or more reprints of the same or different Reviewsare subject t o a discount of 26%.The appropriate remittance, made out to The ChemicalSociety, should accompany any order.“Activation Analysis,” by R. F. Coleman and T.B. Pierce (January, 1967).“Techniques in Gas Chromatography. Part I. Choice of Solid Supports,” by F. J. Palframan“Heterocyclic Azo Dyestuffs in Analytical Chemistry,’’ by R. G. Anderson and G. Nickless“Determination of Residues of Organophosphorus Pesticides in Food,” by D. C. Abbott and“Radioactive Tracer Methods in Inorganic Trace Analysis: Recent Advances,” by J. W.“Gamma-activation Analysis,” by C. A. Baker (October, 1967).“Precipitation from Homogeneous Solution,” by- P. F. S. Cartwright, E. J. Newman and“Industrial Gas Analysis,” by (the late) H. N. Wilson and G. M. S. Duff (December, 1967).“The Application of Atomic-absorption Spectrophotometry to the Analysis of Iron and“Inorganic Ion Exchange in Organic and Aqueous - Organic Solvents,” by G.J. Moody and“Radiometric Methods for the Determination of Fluorine,” by J . K. Foreman (June, 1969).“Techniques in Gas Chromatography. Developments in the van Deemter RateTheory of Column Performance,” by E. A. Walker and J . F. Palframan (August, 1969).“Techniques in Gas Chromatography, Choice of Detectors,” by T. A. Gough andE. A. Walker (January, 1970).“Laser Raman Spectroscopy,’’ by P. J. Hendra and C. J . Vear (April, 1970).“Ion-selective Membrane Electrodes,” by Ern0 Pungor and KlAra T6th (July, 1970).“X-ray Fluorescence Analysis,” by K. G. Carr-Brion and K. W. Payne (December, 1970).“Mass Spectrometry for the Analysis of Organic Compounds,” by A. E. Williams and H. E.“The Application of Non-flame Atom Cells in Atomic-absorption and Atomic-fluorescence“Liquid Scintillation Counting as an Analytical Tool,” by J.A. B. Gibson and A. E. Lally“The Determination of Some 1,4-Benzodiazepines and Their Metabolites in Body Fluids, ”“Atomic-fluorescence Spectrometry as an Analytical Technique,” by R. F. Browner(October, 1974).“The Use of Precipitate Based Silicone Rubber Ion-selective Electrodes and Silicone RubberBased Graphite Voltammetric Electrodes in Continuous Analysis, ” by 2s. FBher,G. Nagy, K. T6th and E. Pungor (November, 1974).“The Examination of Meat Products with Special Reference to the Assessment of the MeatContent,” by D. Pearson (February, 1975).“Chemiluminescence in Gas Analysis and Flame-emission Spectrophotometry,” by J . H.Glover (July, 1976).“The Analytical Role of Ion-selective and Gas-sensing Electrodes in Enzymology,” byG.J. Moody and J. D. R. Thomas (September, 1975).“Thiazolylazo Dyes and Their Applications in Analytical Chemistry,” by HAvard R. Hovind(November, 1975).“Sample Preparation in the Micro-determination of Organic Compounds in Plasma or Urine, ”by Eric Reid (January, 1976).“Recent Advances in the Ring Oven Technique,” by Herbert Weisz (March, 1976).“The Radioimmunoassay of Drugs,” by J. Landon and A. C. Moffat (April, 1976).“Analysis and Assay of Polyene Antifungal Antibiotics,” by A. H. Thomas (May, 1976).and E. A. Walker (February, 1967).(April, 1967).H. Egan (August, 1967).McMillan (September, 1967).D. W. Wilson (November, 1967).Steel,” by P. H. Scholes (April, 1968).J.D. R. Thomas (September, 1968).Part 11.Part 111.Stagg (January, 1971).Spectroscopy,” by G. F. Kirkbright (September, 1971).(October, 1971).by J. M. Clifford and W. Franklin Smyth (May, 1974)July, 1976 SUMMARIES OF PAPERS I N THIS ISSUESpectrophotometric Determination of Parathion andParaoxon Using Alkaline Hydroxylamine Solution for theLiberation of 4-NitrophenolThe half-time for the liberation of 4-nitrophenol from parathion (diethyl4-nitrophenyl phosphorothionate) a t 20 "C in the presence of 0.5 M sodiumhydroxide solution is several hours, but this time can be reduced nearly a1 000-fold when the alkali is replaced with a mixture of 0.5 M sodium hydroxidesolution and 0.67 M hydroxylamine solution. The reaction is almost instan-taneous when the system also contains 33% of ethanol.A procedure isdescribed, based on these findings, for the spectrophotometric determinationof parathion and paraoxon via the 4-nitrophenol liberated. The method issimple and quantitative and does not involve the use of drastic chemicalprocedures such as those required for methods that are currently available.The sensitivity of the method is about 0.1 pmol of parathion. Mixtures ofparathion and paraoxon can be determined by using a selective extractionprocedure.N. RAMAKRISHNA and B. V. RAMACHANDRANIndian Drug Research Laboratory, Poona-411 005, India.Analyst, 1976, 101, 528-532.Ultraviolet Spectrophotometric and Thin-layer ChromatographicDetermination of Pirimiphos-ethyl and Pirimiphos -methylin Insecticide FormulationsTwo methods are described for determining pirimiphos-ethyl and pirimiphos-methyl with an error within &2%. In the ultraviolet spectrophotometricmethod, a solution of the sample in chloroform is purified by column chromato-graphy on Florisil.The insecticides are then hydrolysed in boiling hydro-chloric acid to 2-diethylamino-4-hydroxy-6-methylpyrimidine, which isextracted from the aqueous solution, buffered a t pH 6.5, into chloroformand determined absorptiometrically a t 298 nm in methanol. The thin-layerchromatographic method consists of development of the chromatogram onsilica gel GF25a with hexane - acetone (17 + 3). The isolated insecticide isextracted into methanol with a vacuum extractor and the absorbancemeasured at 248 nm.Results for pirimiphos-ethyl and -methyl obtainedon technical samples and emulsifiable concentrates by the proposed methodscompare favourably with those obtained by gas chromatography, but thethin-layer and gas-chromatographic methods, which are more specific thanthe ultraviolet spectrophotometry, are preferred for application to samplesthat have been stored under adverse conditions. Both proposed methodsare applicable to other formulations, such as powder seed dressings andgranules. Pirimiphos-ethyl and -methyl can be separated either by thin-layerchromatography or by gas chromatography.S . H. YUENImperial Chemical Industries Ltd., Plant Protection Division, Jealott's Hill ResearchStation, Bracknell, Berkshire. RG12 6EY.Analyst, 1976, 101, 533-539.Thin-layer Chromatographic Analysis of Some Triphenodioxazines(1,4-Benzoxazino[2,3- blphenoxazines)Thin-layer chromatographic procedures involving the use of silica-gel plateshave been developed for the separation and identification of tripheno-dioxazines in sub-microgram amounts using non-aqueous developing solventsystems. The compounds are detected by spraying the plates with con-centrated sulphuric acid.S. K. JAIN and R. R. GUPTADepartment of Chemistry, University of Rajasthan, Jaipur-4, India.Analyst, 1976, 101, 540-542.vi

ISSN:0003-2654    

DOI:10.1039/AN97601FP049

出版商:RSC    

年代:1976

数据来源: RSC

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Ju Ly , 19 76 THE ANALYST ix11 CLASSIFIED ADVERTISEMENTS 11The rate for classified advertisements i s 50p a line (or spaceequivalent of a line) u i f h a n extra charge of 20p for theuse of a Box Number. Semi-displayed classijedadvertisements are Lz.00 per single column centimetre(min. 3 cm.)Copy for classified advertisements required not later thanthe 18th of the month preceding the date of publication whichi s on the 16th of each month. Advertisements should beaddressed to J . Arthur Cook, g Lloyd Square, London,WCIX 9BA. Tel.: 01-837 6315FOR SALEAnalyst Vols., 82 (1957) to 100 (1975) Bound. Analytical AbstractsVols., l(1954) to 27 (1974) Bound. Perfect condition. Offers toBoxNo. 241, c/o J. Arthur Cook, 9, Lloyd Square, London WClX SBA.APPOINTMENT VACANTLANCASHIRE COUNTY COUNCIL(Grade A.P.5-S3,825-&4,095 p.a. +- 65312 p.a.Salary Supplement)Applications invited for the above post. Applicants should haveB.Sc.(Chemistry) or A.K.I.C. ,preferably with experience of food anddrugs chemistry.Application forms from Chief Executive/Clerk (Ref: 41/B JH) CountyHall, Preston, PR1 SXJ (Tel. No. Preston 54568, Ext. 666), to bereturned by 6th August 1976.COUNTY LABORATORY-ASSISTANT ANALYSTPlease mentionTHE ANALYSTwhen replying to advertisementsNEWES 676-1 Iron OreES 576-1 Ferro NiobiumES 084-1 Unalloyed SteelEURO-STANDARD SAMPLESDetails of these and theEu ro - Standards produced byBAM and I RSI D available from:Bureau o f Analysed SamplesLtd.Newham Hall, Newby,Middlesbrough, Cleveland TS8 SEATelephone: Middlesbrough 3721 6SPECIALIST ABSTRACTJOURNALSpublished byP.R.M.SCIENCE &TECHNOLOGY AGENCYLTD.Atomic Absorption and EmissionSpectrometry AbstractsVol. 8, 1976, bimonthly f40X-Ray Fluorescence SpectrometryAbstractsVol. 7, 1976, quarterly f 40Gas C h ro rn a to g rap h y- M assSpectrometry AbstractsVol. 7, 1976, quarterly f55Thin-Layer Chromatography AbstractsVol. 6, 1976, quarterly f40Nuclear Magnetic ResonanceSpectrometry AbstractsVol. 6, 1976, quarterly f40Laser-Raman & Infrared SpectroscopyAbstractsVol. 5, 1976, quarterly f40Neutron Activation Analysis AbstractsVol. 5, 1976, quarterly f40X- Ray Diffraction AbstractsVol. 4, 1976, quarterly f40Electron Microscopy AbstractsVol. 4, 1976, quarterly f 40Liquid Chromatography AbstractsVol.3, 1976, quarterly f40Electron Spin Resonance SpectroscopyAbstractsVol. 3, 1976, quarterly f 40Mossbauer Spectroscopy AbstractsVol. 1, 1976, quarterly f40Polarography AbstractsVol. 1, 1976, quarterly f40Sample copies on request from:P.R.M. SCIENCE &TECHNOLOGY AGENCYLTD.,787 HIGH ROAD,NORTH FINCHLEY,LONDON, N 1 2 8JT01-446 382X SUMMARIES OF PAPERS I N THIS ISSUERe-examination of the Microanalysis of Non-ionic Surfactantsthat Contain Polyoxyethylene Chains by the Method Involving SolventThe microanalysis of surfactants of the type R-(O-CH2-CH2),0H by useof a colorimetric method involving solvent extraction of the thiocyanato-cobaltate(I1) complex was re-examined for the pure compounds and formixtures.It was concluded that Beer’s law was not always obeyed, especiallywhen the composition of the mixture was simple, and that the shape of thecalibration graph was markedly dependent on the composition. The limitsof the practical application of the method were considered.AKIO NOZAWA, TOSHIO OHNUMAResearch and Development Department, Nihon Surfactant Industries, Hssune,I tabashiku, Tokyo, Japan.and TATSUYA SEKINEDepartment of Chemistry, Faculty of Science, Science University of Tokyo, Kagura-zaka, Shinjuku-ku, Tokyo, Japan.Analyst, 1976, 101, 543-548.July, 1916Extraction of the Thiocyanatocobaltate(I1) ComplexRapid and Precise Determination of Nitroglycerin by theSchultze - Tiemann MethodAn improved procedure for the quantitative determination of nitroglycerinby use of the Schultze - Tiemann method is described, in which the dis-advantages of the previous procedure are avoided.Thus, time consumedin drying the residue from the ether extraction to constant mass (16-24 h),and in carrying out the oxidation process (30-60 min), is saved by omittingthese two steps. The method is simple and its accuracy has been increasedby carrying out the analyses on larger samples containing from about 50 toabout 200 mg of nitroglycerin.ABDEL FATTAH DAWOUD, A. ABDEL WAHID and A. EL-DAMATYNational Institute for Standards, National Research Centre Building, El-TahrirStreet, P.O. Box 2343, Dokki, Cairo, Egypt.Analyst, 1976, 101, 549-552.Analytical Optoacoustic SpectrometryInorganic, Biochemical and Phytochemical SamplesSome preliminary studies concerned with the application of optoacousticspectrometry to chemical analysis are described and modifications made toimprove the performance of the spectrometer that was discussed in Part Iof this series are reported.This instrument has been used in the investigation of a variety of sampletypes ; several inorganic species, including rutile and anatase titanium(1V)oxide, organometallic and water-sensitive compounds have been examinedand optoacoustic spectra have been obtained from a series of haemoproteinsof biological origin and from botanical samples.Where comparisons arepossible the spectra obtained by using optoacoustic spectrometry are similarto those obtained by use of conventional transmission or reff ectance spectro-metry. In general, however, optoacoustic spectrometry has the advantage ofthe requirement of only small (microlitre or microgram) amounts of sample.Spectra obtained from fresh leaf tissue indicate that optoacoustic spectrometryhas a particular advantage over conventional techniques in that for hetero-geneous samples of this type it is possible to generate separate spectra fromdifferent compounds by observing spectra in a phase-delayed mode; this effectcan be used to advantage in the examination of surface layers without interfer-ence from substrate material.M.J. ADAMS, B. C. BEADLE, A. A. KING and G. F. KIRKBRIGHTDepartment of Chemistry, Imperial College, London, SW7 2AY.Part 11. Ultraviolet and Visible Optoacoustic Spectra of SomeAnalyst, 1976, 101, 553-561July, 1976 THE ANALYST xiSelected Annual Reviewsof the Analytical SciencesThree volumes in this series have now beenpublished, the most recent in December 1974Volume 3CONTENTS'Solvent Extraction in Inorganic AnalyticalChemistry,' by S.J. Lyle'Selective Ion-sensitive Electrodes,' byG. J. Moody and J. D. R. Thomas'The Application of Separated Flames inAnalytical Atomic Spectrometry,' by M. S.Cresser, P. N. Keliher and G. F. KirkbrightPp. vi + 162 f 6.00ISBN 0 85990 203 XEarlier volumes still available :Volume 7, 1977CONTENTS'Molecular-sieve Chromatography,' by D. M. W.Anderson, I. C. M. Dea and A.Hendrie'Photoluminescence and Chemiluminescence inInorganic Analysis,' by L. S. Bark and P. R. Wood'Recent Developments in Activation Analysis,' byT. B. Pierce'Atomic Absorption Spectroscopy,' by P. Platt'Catalytic Methods in Analytical Chemistry,' byG. SvehlaPp. vi + 269 ISBN 085990201 3 f 5.00Volume 2, 7972CONTENTS'The Techniques and Theory of Thermal AnalysisApplied to Studies on Inorganic Materials withParticular Reference to Dehydration and SingleOxide Systems,' by D. Dollimore'Developments in Ion Exchange,' by F. Vernon'Thermometric and Enthalpimetric Titrimetry,' byL. S. Bark, P. Bate and J. K. GrimePp. vi + 149 ISBN 085990202 I f 5.00Members' price f3.00 each volumeOrders should be sent through your usualbookseller or direct, enclosing remittance, to-The Publications Sales OfficerTHE CHEMICAL SOCIETYBlackhorse Road, Letchworth,Herts.SG6 IHN, EnglandMembers must write direct to the above addressenclosing the appropriate remittance.ELLIS HORWOOD SERIES INANALYTICAL CHEMISTRYConsultant Editor:Dr. R. A. Chalmers, University of AberdeenFounded as a library of fundamental books on important andgrowing subject areas in analytical chemistry, this series willserve chemists in industrial work andresearch, and in teachingor advanced study.PUBLISHED OR IN ACTIVE PREPARATION:HANDBOOK OF PROCESS STREAM ANALYSISK. J. Clevett, Crest Eng. (UK) Inc. $36.30/f16.50AUTOMATIC METHODS IN CHEMICAL ANALYSISJ. K. Foreman; P. Stockwell, Laboratory of the GovernmentChemist, London $33.00/€15.00PARTICLE SIZE ANALYSISZ.K. 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Vydra. J. Heyrovsky lnst. of Polarography, Prague; K.Stulik, Charles University, Prague; E. Julakova, The Statelnst. for Control of Drugs, Prague In PressLABORATORY HANDBOOK OF THIN LAYER ANDPAPER CHROMATOGRAPHYJ. Gasparic 8 J. Churacek, Universityof ChemicalTechnology,Pardubice In PressANALYTICAL APPLICATIONS OF COMPLEXEQUlLl BRlAJ. Inczedy, Univ. of Chem. Eng., VeszpremION SELECTIVE MEMBRANE ELECTRODESC. Liteanu and I.C. Popescu, University of Cluj, RumaniaHANDBOOK OF CHROMATOGRAPHIC AND ALLIEDSEPARATION TECHNIQUES 2nd (Revised) Ed.0. Mikes, Inst. of Organic 8 Biochem., Czechoslovakia,Academy of Sciences, Prague, et al. In PressAll these books are published byELLW HORWOOD LTD., CHICHESVER,and distributed by$41.80/f 19.00In Press$42.90/€19.50In PressIn PressJOHN WILEY & SONS LTDBaffins Lane Chichester * Sussex PO19 1 UD . Englanxii SUMMARIES OF PAPERS IN THIS ISSUEDetermination of Saccharin in Soft Drinks by Molecular EmissionCavity AnalysisSaccharin (20-800 p.p.m.) is assayed in soft drinks and soft drink concentratesby extraction into ethyl acetate and determination by molecular emissioncavity analysis, based on the S, emission generated by the saccharin, usinga nitrogen-diluted hydrogen - air flame.R.BELCHER, S . L. BOGDANSKI, R. A. SHEIKH and ALAN TOWNSHENDJULY, 1976Department of Chemistry, University of Birmingham, P.O. Box 363, Birmingham,B15 2TT.Analyst, 1976, 101, 562-565.Detection and Determination of PolynuclearAromatic Hydrocarbons by Luminescence SpectrometryPart 111. Luminescence Excitation SpectraAn apparatus has been constructed to permit the examination of the lumines-cence excitation spectra of polynuclear aromatic hydrocarbons that exhibitthe Shpol'skii effect in their low-temperature luminescence emission inn-alkane solvents at 77 K. Excitation spectra and detection limits fora range of polynuclear aromatic hydrocarbon components are presented.R. FAROOQ and G.F. KIRKBRIGHTUtilising the Shpol'skii Effect at 77 KDepartment of Chemistry, Imperial College of Science and Technology, London,SW7 2AY.Analyst, 1976, 101, 566-573.Simultaneous Extraction and Concentration of Cadmium andZinc from Soil ExtractsA method for the simultaneous extraction and concentration of cadmium andzinc from soil extracts is described and evaluated. The procedure, usingdithizone - carbon tetrachloride extraction at pH 4.5, is simple and reliable,giving an essentially quantitative recovery of cadmium and zinc added tocalcium chloride extracts of several contrasting soils. The method was usedto evaluate the effect of long-term superphosphate fertiliser addition on thecadmium and zinc contents of soil.A. H.C. ROBERTS, M. A. TURNER and J. K. SYERSDepartment of Soil Science, Massey University, Palmerston North, New Zealand.Analyst, 1976, 101, 574-578.Variation in Ambient Temperature as a Source of Error inAbsorbance Measurements Made with Single-beamSpectrophotometersSmall changes (&2 "C) in ambient temperature were found to affect the zeroabsorbance calibration of two dissimilar single-beam spectrophotometers ofmodular construction. The temperature-sensitive modules of each instru-ment were located and their thermal responses measured. When all moduleswere operated at ambient temperature (23-27 "C) and monochromator driftwas corrected, the thermal drifts were sufficiently large to cause a significanterror in applications in which it is not the normal practice to re-calibrate zeroabsorbance after each measurement, e.g., atomic-absorption and continuousautomated spectrophotometry.PAUL J. MILHAM and COLIN C. SHORTBiological and Chemical Research Institute, New South Wales Department ofAgriculture, Private Mail Bag 10, Rydalmere, N.S.W. 21 16, Australia.AHaZyst, 1976, 101, 579-58July, 1976 SUMMARIES OF PAPERS I N THIS ISSUEIonisation Interferences in Carbon Furnace Atomic-absorption andAtomic - emission SpectrometryCornrnunicatioizJ. M. OTTAWAY and F. SHAWDepartment of Pnre and Applicd Chemistry, University of Strathclyde, CathedralStreet, Glasgow, G1 1XL.Analyst, 1976, 101, 582-585,A Computerised Programmable Monochromator for FlexibleMulti-element Analysis with Special Reference to theInductively Coupled PlasmaComnzunicationP. W. J. M. BOUMANS, G. H. VAN GOOL and J. A. J. JANSENPhilips Rescarch Laboratories, Einclhoven, The Netherlands.Analyst, 1976, 101, 585-587.Electrothermal Atomisers as Resonance DetectorsConznzunicationJ. B. DAWSON, E. GRASSAM and D. J. ELLIS...X l l lUniversity of Leeds, Department of Medical Physics, The General Infirmary, Leeds,LSl 3EX.Analyst, 1976, 101, 587-588

ISSN:0003-2654    

DOI:10.1039/AN97601BP055

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

JULY 1976 The Analyst Vof. 101 No. 1204 Properties and Uses of the Colorimetric Reagents 2-Nitroso-5-dimethylaminophenol and 2-N itroso-5- diethylaminophenol for Cobalt A Review* Kyoji Tbei and Shoji Motomizu Department of Chemistry, Faculty of Science, Okayaina University, Tsushima, Okayama-shi, Japan Summary of Contents Introduction Nitrosophenol and nitrosoiiaphthol derivatives Synthesis of nitroso-DMAP and nitroso-DEAP Properties of nitroso-DMAP and nitroso-DEAP Cobalt complexes of nitroso-DMAP and nitroso-DEAP Determination of cobalt with nitroso-DMAP and nitroso-DEAP Determination of cobalt in pure nickel salts Spectrophotometric determination in aqueous solution Spectrophotometric determination by solvent extraction Spectrophotometric determination in aqueous solution Spectrophotometric determination by solvent extraction Determination of cobalt in iron and steel Spectrophotometric determination of trace amounts of cobalt in pure reagent chemicals Preparation of sample solution Determination of cobalt Determination of cobalt in sea water with niti-oso-DEAP Determination of cobalt in uranium oxide (U,O,), pure uranium and a uranyl salt Preparation of sample solution Procedure I, for samples containing more than 5 p.p.m.of cobalt Procedure 11, for samples containing 0.5-5 p.p.m. of cobalt Procedure 111, for samples containing 0.01-0.5 p.p.m. of cobalt Determination of cobalt Conclusion Introduction Cobalt is the 27th element and is situated a t the centre of the first long period in the Periodic Table. It belongs to the transition metal group and its properties resemble those of iron and nickel rather than those of rhodium or iridium.Cobalt usually co-exists with iron and nickel in the natural world. Its oxidation numbers are I1 and 111; as cobalt(I1) it forms mainly simple salts, while the complex salts are almost all cobalt(II1). A great many complex salts of cobalt are known and they are, in general, very stable, ie., they resist attack by acids and bases, and also oxidation and reduction. Almost all of the organic reagents for deter- mining metal ions are also useful for cobalt because cobalt ions can react with all electron- donating atoms such as oxygen, nitrogen and sulphur. Therefore, many organic reagents for cobalt have been reported. Among the organic reagents, nitrosophenol and nitroso- naphthol derivatives are specific for cobalt.Nitrosophenol and Nitrosonaphthol Derivatives The first synthetic organic reagent used for determining a metal ion was 1-nitroso-%naphthol, which was used for the separation of cobalt from nickel by Ilinski and von Knorrel in 1885. Since that time, the derivatives of nitrosonaphthol and nitrosophenol have been known to For details see summaries in advertisement pages. 497 * Reprints of this paper will be available shortly.498 T ~ E I AND MOTOMIZU : PROPERTIES AND USES OF Analyst, VoZ. 101 be specific for cobalt, and many of these derivatives have been proposed as colorimetric reagents for cobalt. The authors synthesised 25 derivatives of nitrosophenol and nitrosonaphthol (Fig. 1) , 2 9 3 which were all capable of reacting with cobalt to form complexes.Their spectrophoto- metric properties were determined4 and are listed in Table I. According to their structures, SO3 H (115 SO3 H OH CI (215 (316 (417 (5P NO (615 (9 l8 YO QJyH COOH (1 218 OH NO NO OH (1017 OH OH OH OH (2017 (211'0 &NO &NO @NO C I y ! q N O (H5 C2 12 N H3 c CH3 H3 CI CI (22) lo (2319 (241' (2519 Fig. 1. Configuration of nitrosonaphthol and nitrosophenol derivatives. These nitroso compounds were synthesised according to the literature reference indicated beside the configuration number.July, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW 499 they are classified into five groups: Group I consists of the derivatives of 2-nitroso-l-naphthol, Group I1 the derivatives of l-nitroso-2-naphthol, Group I11 the derivatives having a substituent at the 4-position of nitrosophenol, Group IV those having a substituent at the 5-position of nitrosophenol and Group V the derivatives of nitrosophenol substituted in two positions.TABLE I MOLAR ABSORPTIVITIES OF COBALT COMPLEXES Aqueous solution Extraction r L 'L I A Reagent pH* Group I- 1 5-8 2 5-8 3 7-8 4 5 5-8 - Group II- 6 4-6 8 6-7 9 5-6 10 7-8 11 6-7 12 6-7 13 6-8 7 4-6 Group III- - 14 15 16 - - Group I V- - 17 18 19 7 20 6 21 5-7 - 22 5-6 Grot@ V- - 23 24 25 - - x 1041 Amax./nm 1 mol-l cm-l pH* 368 3.3 7-8 368 3.8 5-7 368 3.3: 7-8 - 5-8 368 2.9: 5-8 - 410 416 410 450 400 450 430 424 3.8 3.5 3.5 3.6 3.7$ 3.5: 3.5 3.1: 4-7 5-6 5-8 5-7 7-9 6-9 4 7-8 - - 5-6 - 6-9 386 5.2 7 380 5.8 6-7 445 4.9 5-7 - 442 5.1 5-6 E x 1oq A,,,./nm 1 mol-l cm-l 368 4.0 368 3.9 362 3.3 361 3.5 3 62 3.5 410 424 420 456 410 456 428 414 3.4 3.6 3.5 3.6 3.4 3.1 3.1 3.4 352 3.4 352 3.4 356 3.0 368 3.6 363 3.2 383 4.5 392 4.9 456 6.0 462 6.1 366 3.2 361 3.8 370 3.3 Solventt CHCl, + 2 CHC1, + 2 CHCl, + 2 CHC1, + W CHCl, + W CHCl, + 2 CHC1, + 2 CHCl, + 2 CHC1, + Z CHCl, + 2 BA CHC1, + 2 CHCl, + W CHCl, + W CHC1, + W CHC1, + W CHCl, + W CHC1, + W CHCI, + W CHCI, + 2 DCE + W(HC1) DCE + W(HC1) or CHCl, + W(HC1) B + W CHC1, + W CHCl, + W * The pH range in which the absorbances of the complex were constant and a t a maximum when the concentrations of reagent and cobalt were 1 x t Extracting solvents : CHCl,, chloroform ; BA, benzyl alcohol ; DCE, 1,2-dichloroethane; B, benzene.2, The extraction was carried out in the presence of zephiramine (tetradecyldimethylbenzylammonium chloride).W, After the extraction, the organic phase was washed with 1 N sodium hydroxide or 1 + 2 hydrochloric acid. M and 1 x M, respectively. $ The mixture of water and 1,Cdioxan. In Table I the absorption maxima and molar absorptivities ( E ) of the cobalt complexes in aqueous and organic solutions are shown. The cobalt complexes of Group I and I1 derivatives have absorption maxima at about 370 nm and at higher than 400 nm, respectively, and their molar absorptivities are 3 4 x lo4. In Groups 111, IV and V, the wavenumber of the absorption maximum of the cobalt complex in chloroform is plotted against the Hammett (a) value (Fig. 2). The o m value is used in Group 111, and the ap value in Group IV.The a value determined for the compound with two substituents at the 3- and 4- positions (3-chloro and 4-methyl) is used for reagent 24.500 Analyst, VoZ. 101 In Fig. 2 results for two types of reagent are shown, one containing a halogen group and the other an electron-donating group. In both instances good linearity is obtained. From this result it appears that the smaller the a value the longer the wavelength of the absorption maximum becomes. Also, the molar absorptivity increases with the wavelength of the absorption maximum. On considering these results, 2-nitroso-5-dimethylaminophenol (nitroso-DMAP) and 2-nitroso-5-diethylaminophenol (nitroso-DEAP) are found to be the most sensitive reagents for cobalt. T ~ E I AND MOTOMIZU: PROPERTIES AND USES OF Synthesis of Nitroso-DMAP and Nitroso-DEAP Nitroso-DMAP and nitroso-DEAP are obtained by the nitrosation of NN-dimethyl-3-amino- phenol and NN-diethyl-3-aminophenol in solution in hydrochloric acid with sodium nitrite solution.1° Thirty-three grams of NN-dimethyl-3-aminophenol are dissolved in 35 ml of concentrated hydrochloric acid (sp.gr. 1.18). After cooling the solution to below 5 "C, a molar equivalent of sodium nitrite (17 g in 40 ml of water) is added dropwise with stirring. The precipitate is filtered and recrystallised three times from solution in hydrochloric acid. The purified nitroso-DMAP hydrochloride salt (nitroso-DMAP. HC1) consists of yellow, needle-like crystals. The elemental analysis is as follows. Found: C, 47.6; H, 5.7; N, 13.5%.Calculated for C,HllN202C1: C, 47.4; H, 5.5; N, 13.8%. Nitroso-DEAP is obtained in the same way as nitroso-DMAP. These yellow, needle-like crystals are singly hydrated (CloH15N,02C1.H,0). The elemental analysis is as follows. Found: C, 48.2; H, 6.6; N, 11.4%. Calculated for CloH,,N20,C1: C, 48.3; H, 6.9; N, 11.3%. Properties of Nitroso-DMAP and Nitroso-DEAPI1J2 is stable for at least 1 month.- Nitroso-DEAP is also stable less stable than nitroso-DMAP in aqueous solution. Nitroso-DMAP.HC1 and nitroso-DEAP.HC1 dissociate in Nitroso-DMAP hydrochloride is stable for at least 2 years. However, the aqueous 10-4 M solution at pH 6 is not so stable so that the absorbance of the reagent decreases with time, the decrease being about 1.5% in 4 h. Nitroso-DMAP dissolved in 0.01 M hydrochloric acid in acidic soluti6n but is a little aqueous solution as follows : u 6x2 H2R (yellow) HR (red) Q- I ?- R (red) where X is a methyl or ethyl group.The pKa1 and pKa2 values are obtained spectrophoto- metrically and are shown in Table 11. Nitroso-DMAP and nitroso-DEAP can be extracted into 1 ,Z-dichloroethane. The absorb- ance spectra of the reagents in the organic phase, following extraction from the aqueousJuly, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW TABLE I1 CONSTANTS OBTAINED FOR NITROSO-DMAP AND NITROSO-DEAP 501 Nitroso-DXAP Nitroso-DE AP p K a 1 ( p = 0.1) . . . . . . . . 2.69 2.83 pKa2 ( p = 0.2) . . .. . . . . 8.40 8.38 A,,,. (MR,) (in aqueous solution, pH 6.3) . . 442 nm Amax. (HR) (in 1,2-dichloroethane) .. 404 nm 408 nm Amax. (MR,) (in 1,2-dichloroethane) . . 456 nm 462 nm E Y R ~ (in 1,2-dichloroethane) . . . . 6.0 x lo4 (456 nm) 6.2 x lo4 (462 nm) 1ogDRR ( p = 0.1) . . . . . . . . 1.42 2.35 log KYR3 ( p = 0.1) . . . . .. . . 26.8 24.7 445 nm logK ( p = 0.1) . . . . .. . . 0.42 -0.21 10gDMR~ * - .. . . .. . . 3.1 7.4 S M R 3 . * . . . . . . .. . . 6.5 x l o - 5 ~ 3.6 x 10-6R.r phase at various pH values, are all of the same type and show the same absorption maxima a t 404 (nitroso-DMAP) and at 408 nm (nitroso-DEAP), respectively. The distribution ratio of nitroso-DMAP or nitroso-DEAP, qR, is measured spectrophoto- metrically and the relationship between log qR and pH is shown in Fig. 3. 3.0 1 'E 2.8 0 . * 2.6 x, n 5 2.4 C 2.0 - -0.8 -0.4 0 0.4 0.8 Hammett ( 0 ) value Fig.2. Graph of wave- number of absorption maximum of the cobalt complex in chloro- form against Hammett (u) value. The number indicates the nitroso compound in Table I. 3.0 B 1 2.0 1 .o [r 0 - g o -1 .o -2.0 -3.01 4 I 1 I I 0 2 4 6 8 1 0 1 2 1 4 PH Fig. 3. Graphs of log qR vwws pH. A, Nitroso- DMAP; and B, nitroso-DEAP. The graph of log q R against pH has break points at pKal and pKa2 and the lines below pK,, and above PKa, are straight with slopes of 1 .O and -1 .O, respectively. Between pKal and pKa2 the slope is zero and the value of qR corresponds to the partition coefficient, DHR. From Fig. 3, the regions in which the reagent is more than 99% in the aqueous phase are below pH -0.8 or above pH 12 (nitroso-DMAP), and below pH -1.5 or above pH 13 (nitroso- DEAP). Hence, the reagent in the organic phase can be removed by addition of sodium hydroxide solution or concentrated hydrochloric acid.Cobalt Complexes of Nitroso-DMAP and Nitroso-DEAP11J2 The cobalt ion reacts with nitroso-DMAP and nitroso-DEAP at a neutral pH to form red complexes. In Figs. 4 and 5 the absorbance spectra of the complexes and the reagents in aqueous solution and in 1,2-dichloroethane are shown. These cobalt complexes, both in aqueous solution and when extracted into 1,2-dichloro- ethane, are found to be of 1 : 3 composition by the molar ratio and continuous variation methods. The formation constants, KHRB, of these cobalt complexes are determined spectro- photometrically; the constants obtained are shown in Table 11.502 T ~ E I AND MOTOMIZU: PROPERTIES AND USES OF Analyst, VoZ.101 Wavelength/nm Fig. 4. Absorption spectra of nitroso- DMAP and its cobalt complex. A, reagent concentration 3 x 1 0 - s ~ , pH 6.3; B, re- agent concentration 3 x M, cobalt concentration 1 x M, pH 6.3; C, reagent concentration 5 x M ; D, reagent blank; and E, cobalt concentration 1 x 10-5 M. Reference solvent (l-cm cell) : A and B, aqueous solution; C-E, 1,Z-dichloro- ethane [D and E washed out with hydro- chloric acid - water (1 + S)]. 340 380 420 460 500 540 580 Wavelengthhm Fig. 5. Absorption spectra of nitroso- DEAP and its cobalt complex. A, reagent concentration 3 x M, pH 6.3, 10-cm cell; B, reagent concentration 3 x ~ O - S M , cobalt concentration 1 x 10-6 M, pH 6.3, 10-cm cell; C, reagent concentration 5 x M, l-cm cell; D, reagent blank, l-cm cell; and E, cobalt concentration 1 x 10-6 M, l-cm cell.Reference solvent: A and B, aqueous solution ; C-E, 1,2-dichloroethane [D. and E washed out with hydrochloric acid - water (1 + l)]. The cobalt complexes, once formed in aqueous solution, are stable even in strongly acidic solutions such as 3 N sulphuric acid or 1 . 5 N hydrochloric acid for about 1 d, and are not decomposed, even by the addition of EDTA. Cobalt, however, does not form complexes with nitroso-DMAP and nitroso-DEAP at all when EDTA is present or when the solution is strongly acidic. The cobalt complexes extracted into 1,2-dichloroethane are stable for at least 1 week and are not decomposed when the organic phase is washed with 1 N potassium hydroxide solution, 1 + 2 hydrochloric acid or EDTA solution.Cobalt - nitroso-DMAP and - nitroso-DEAP complexes are slightly soluble in water. The solubilities, &R3, of cobalt - nitroso-DMAP and - nitroso-DEAP complexes in water are 6.5 x and 3.6 x 1 W 6 ~ , respectively. From Fig. 3, it can be seen that most of the reagent is present in the organic phase in the pH range between pKBl and pKa2. The complex formed is also readily extracted into the organic phase. The following equilibrium is therefore considered. When pK,, < pH < pKrt2, M(a) + 3HR,o) + MR3,o) + 3H(a) From equation ( l ) , equation (1') can be derived: [MR310 = log K + 3pH . . .. . . (1') [MI a [HRI o log K' = log The graph of log K' against pH shows good linearity and the slope is about 3. The calcu- lated values of log K for nitroso-DMAP and nitroso-DEAP are 0.42 and -0.21, respectively.The partition coefficient of the cobalt complex, &R3, is calculated from equation (2) : The calculated values of log DMR3 for nitroso-DMAP and nitroso-DEAP are 3.1 and 7.4, respectively (Table 11). log DYR3 = log K - log KYB3 + 3pKa2 + 3 log DnR . . ' * (2)July, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW 503 Determination of Cobalt with Nitroso-DMAP and Nitroso-DEAP Although the reagents react quantitatively with cobalt, some metal ions, such as iron(III), iron(II), copper(I1) and nickel(II), can also react with the reagents and the resulting complexes are extracted into the organic phase to some extent. In most instances, the effect of the foreign ions is effectively eliminated by the addition of citric acid buffer solution (pH 5.3), and by the solvent extraction procedure.The maximum permissible concentration of these ions is shown in Table 111. The effect of the other co-existing ions is shown in Table IV. TABLE I11 EFFECT OF NICKEL, COPPER, IRON(II) AND IRON(III) IONS Cobalt solution, 1 x M ; nitroso-DMAP solution, 5 x M. Citric acid buffer solution, 2 M (pH 5.3); aqueous phase, 5 ml of cobalt solution + buffer solution + nitroso-DMAP solution; organic phase, 5 ml of 1,2-dichloroethane. Buffer Permissible Metal ion solution/ml Reagentlml concentration/M Ni2+ 1 1 5 x 10-2 3 3 1 x 10-1 CU2f 1 1 2 x 10-4 Fe2+ 1 1 3 x 10-4 Fe3+ 2 2 2 x 10-1 1 1 1 x 10-1 The excess of nitroso-DMAP or nitroso-DEAP in the organic phase can be eliminated with 1 M sodium hydroxide solution or with 1 + 2 hydrochloric acid.The cobalt complexes, however, remain stable in the organic phase. The absorption spectra (E) and (D) in Figs. 4 and 5 are those of the complex and the reagent blank after removal of the reagent, respectively. The absorbance maxima of the complexes of nitroso-DMAP and nitroso-DEAP occur at 456 and 462 nm, respectively, while that of the reagent blank is negligible. TABLE IV EFFECT OF CO-EXISTING IONS Cobalt, 1 x 10-5 M; nitroso-DMAP, 1 x 10-4 M; extracting solvent, 1,2-dichloroethane. Permissible concentration/M Ions 10-2 2+, Hg+ 10-4 Cr3+, A13+, Pb2+ 10-5 Sna+ Above 10-1 Alkali metal ions, NO3-, C1-, C104-, Sod2-, SCN-, F-, Br- 10-3 ~~~'Bc,"S:r'AHggc, Zn2+, Cd2+, Mn2+ A further merit of nitroso-DMAP is seen when the reagent has to be used in aqueous solution.In this event, the absorption of the co-existing reagent is not so small at the absorption maximum of the complex. In order to minimise the absorption of the reagent, the solution is acidified after the cobalt complex has formed at about neutral pH, and then the absorption is measured at a longer wavelength than that of the maximum, at which the absorption of the reagent is very small. Even at that wavelength (530 nm) the sensitivity is greater than that of the other 2-nitrosonaphthols, such as nitroso-R salt. Determination of Cobalt in Pure Nickel Salts Cobalt will, in the natural world, co-exist with iron, copper and nickel. In commercial pure nickel salts, micro-amounts of cobalt (about 0.02% or more) will also be present.Therefore, in the presence of nickel ions cobalt was determined by extraction as the thio- cyanate.13-ls Generally, as the chelating and complexing agents with which the cobalt ion reacts also react with the nickel ion, the determination of cobalt in the presence of nickel is very difficult. However, the determination of cobalt according to the following procedures is very simple and precise.504 Analyst, VoZ. 101 Spectrophotometric Determination in Aqueous SolutionL6 Dissolve about 0.1-0.2 g of a nickel salt of analytical-reagent grade or about 0.05 g of extra-pure reagent in distilled water and dilute the solution to 50 ml. Pipette 5 ml of the sample solution into a stoppered test-tube and to it add 1 ml of citric acid buffer solution (2 M, pH 5.3), allowing the mixture to stand for 10 min.Add 1 ml of a 5 x M aqueous solution of nitroso-DMAP, mix thoroughly and allow the mixture to stand for 10 min. Next add 3 ml of 1 + 1 hydrochloric acid and again mix. Then, measure the absorbance against the reagent blank at 530 nm in a cell of l-cm path length. For a reagent blank, use a solution that is prepared by mixing 5 ml of the same sample solution and 3 ml of 1 + 1 hydrochloric acid, adding 1 ml each of buffer solution and the nitroso-DMAP solution to it. The calibration graph is made by using solutions containing known amounts of cobalt [(04) x MI. The results obtained by use of the proposed method for determining cobalt in commercial nickel salts are given in Table V. This method can conveniently be applied to pure nickel salts con- taining about 0.002~0 or more of cobalt.However, the absorbance of the reagent blank is slightly larger than that obtained when using solvent extraction (absorbance at 530nm, 0.04). TGEI AND MOTOMIZU : PROPERTIES AND USES OF TABLE V DETERMINATION OF COBALT I N NICKEL SALTS I N AQUEOUS SOLUTION Sample Supplier A A B B C C D Salt NiSO, . 6H,O Ni(N03),.6Hz0 NiS0,.6H20 Ni(N03), .6Hz0 NiC1,. 6H,O Ni( NO,), .6H,O NiS0,.7H20 Amount taken/ Grade* g per 50 ml a 0.203 7 a 0.198 5 a 0.202 1 a 0.204 8 e 0.040 4 e 0.036 9 e 0.041 7 Absorbance 7 0.574 -J= 0.001 0.556 f 0.005 0.285 -J= 0.001 0.414 * 0.001 0.506 5 0.001 0.449 0 0.576 f 0.002 Cobalt content, yo 0.054 f 0 0.053 f 0.001 0.027 f 0 0.038 f 0.001 0.238 f 0 0.232 f 0 0.263 f 0.001 * a and e denote analytical-reagent grade and extra-pure reagent, respectively.t Reference, reagent blank. Spectrophotometric Determination by Solvent Extraction1' Dissolve about 0.1 g of an analytical-reagent grade nickel salt, or the equivalent amount of extra-pure reagent, in distilled water and dilute the solution to 100 ml. Pipette 5 ml of the sample solution into a stoppered test-tube and add to it 1 ml of citric acid buffer solution (2 M, pH 5.3) ; mix the solutions thoroughly. Add 1 ml of nitroso-DMAP solution (5 x 10-3 M) and again mix, then allow the mixture to stand for about 5 min. Shake this mixed solution with 5 ml of 1,2-dichloroethane for 30 s and back-extract the excess of the reagent and the nickel and other metal ions with 5 ml of 1 + 2 hydrochloric acid.Then, filter the organic phase through a dry filter-paper (5 cm diameter) and measure the absorbance at 456 nm in a cell of l-cm path length. The calibration graph is made by using solutions containing known amounts of cobalt [(O-1.4) x MI. The results obtained by using the proposed method for determining cobalt in commercial nickel salts are given in Table VI. This method is somewhat more troublesome than the determination in aqueous solution. However, it has some advantages over the aqueous method; the reagent blank is very small (about 0.004), the sensitivity is high, and when 3 ml of buffer and nitroso-DMAP solutions are used, cobalt at a level of about 0.001% in nickel salts can be determined. Determination of Cobalt in Iron and Steel Cobalt in iron and steel was determined colorimetrically with nitroso-R salt ,1538 2-nitroso- l-naphthol,lg l-nitros0-2-naphthol~~ and isonitrosomalonylguanidine.21 The methods using these reagents give molar absorptivities of (14) x lo4. Compared with these methods, that using nitroso-DMAP possesses many advantages. The procedures are as follows.Spectrophotometric Determination in Aqueous SolutionL6 Dissolve about 0.4-0.8 g of the iron or steel samples containing about O.Olyo of cobalt, orJuly, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW TABLE VI DETERMINATION OF COBALT IN NICKEL SALTS BY SOLVENT EXTRACTION Sample 505 Supplier A A B B C C D Salt Grade * NiS0,.6H20 a Ni(NO3),.6H,O a NiSO,. 6H,O a Ni(N0,),.6H20 a NiCl, .6H,O e Ni(N0,),.6H20 e NiSO4.7H,O e Amount taken/ g per 100 ml 0.080 0 0.080 0 0.100 0 0.100 0 0.020 0 0.020 0 0.020 0 Absorbancet 0.439 & 0.001 0.526 & 0.003 0.272 f 0.002 0.408 & 0 0.514 & 0.001 0.493 f 0.005 0.542 0.003 Cobalt content, yo 0.054 0.065 0.027 0.041 0.254 0.245 0.268 * a and e denote analytical-reagent grade and extra-pure reagent, respectively.t Reference, reagent blank. less than 0.4 g of samples containing more than 0.02% of cobalt, in 3-6 ml of aqua regia, using heat to aid dissolution. After evaporating until salts are precipitated, add about 1 ml of concentrated hydrochloric acid and redissolve the salts. Dilute this solution to 100 ml with water and use it as a sample solution. The amount of cobalt in the sample solution is deter- mined by using the same method as in the solution of the nickel salts.The results obtained are given in Table VII. The proposed method can conveniently be applied to iron and steel samples containing more than 0.01% of cobalt. However, the reagent blank is relatively large because the iron(II1) ion has its maximum absorption at 530 nm. When the solution 0.1 M in iron(II1) ion was used, the absorbance of the reagent blank was about 0.08. TABLE VII DETERMINATION OF COBALT IN IRON AND STEEL IN AQUEOUS SOLUTION Amount taken/ Cobalt Absorbance* content found, yo NBS 55e (0.007%) . . .. 0.805 5 0.143 & 0.001 0.006 8 f 0.000 1 NBS 126b (0.032%) . . .. 0.202 2 0.168 0.001 0.031 5 f 0.000 2 Sample (cobalt content) g per 100 ml NBS 19g (0.012%) . . .. 0.502 8 0.151 f 0 0,011 4 f 0 NBS lOle (0.18%) .. .. 0.104 6 0.521 f 0.002 0.190 f 0.001 * Reference, reagent blank. Spectrophotometric Determination by Solvent Extraction22 Dissolve 0.5-1 g of the iron or steel samples containing about O . O l ~ o of cobalt, or less than 0.5 g of samples containing more than 0.02% of cobalt, in 3-5 ml of aqua regia, using heat to aid dissolution. Dilute this solution to 100 ml with water, then pipette 5 ml into a stoppered test-tube, add to it 1 ml of citric acid buffer solution (2 M, pH 5.3) and mix. Next add 1 ml of nitroso-DMAP solution (5 x 10-3 M), again mix thoroughly and allow the mixture to stand for 5 min. Shake the mixture with 5 ml of 1,2-&chloroethane for 30 s and back-extract the excess of reagent, and the chelates of other metals, with 5 ml of 1 + 2 hydrochloric acid.Filter the organic phase through a dry filter-paper and measure its absorbance at 456 nm. The results obtained are given in Table VIII. This method is again more troublesome than TABLE VIII DETERMINATION OF COBALT IN IRON AND STEEL BY SOLVENT EXTRACTION Amount taken/ Cobalt content found, yo NBS 55e (o.oo7y0) . . .. 0.504 1 0.350 & 0.004 0.006 8 f 0.000 1 NBS 126b (0.032%) . . .. 0.222 2 0.667 & 0.003 0.032 8 f 0.000 1 NBS lOle (0.18%) . . .. 0.030 0 0.564 0.006 0.185 f 0.002 Sample g per 100 ml Absorbance* NBS 19g (0.012%) . . .. 0.503 9 0.577 & 0.002 0.011 3 f 0.000 1 * Reference, reagent blank,506 Analyst, VoZ. 101 the determination in aqueous solution. However, it is sensitive and the absorbance of the reagent blank is very small.When 2 ml of citric acid buffer and nitroso-DMAP solutions are used, cobalt at a level of 0.001% can be determined by this method. T ~ E I AND MOTOMIZU: PROPERTIES AND USES OF Spectrophotometric Determination of Trace Amounts of Cobalt in Pure Reagent Chemicals23 Trace amounts of cobalt are contained in pure reagent chemicals, such as alkali metal salts (10-7-10-870), iron(II1) salts (more than and hydrochloric acid. Cobalt in these pure chemicals was determined by, for example, spectr~photometry,~~ emission spectro~copy~~ and spectrographic analysis,26 following solvent extraction or co-precipitation. By use of solvent extraction - spectrophotometry and nitroso-DMAP, trace amounts of cobalt in com- mercial pure chemicals were determined as follows.Preparation of Sample Solution Sodium and potassium salt solutions, 10-30 g per 100 ml. Dissolve the required amounts of sodium and potassium salts in distilled water. Ammonia, sodium hydroxide and hydrochloric acid solutions. Dilute or dissolve ammonia solution and sodium hydroxide in distilled water and then neutralise the solutions with hydrogen chloride from a gas cylinder. Dilute hydrochloric acid with distilled water and then neutralise it with the ammonia or sodium hydroxide solution, the cobalt content of which is known. Iron(I1I) salts. Weigh the required amounts of iron(II1) salts into a beaker and add citric acid buffer solution (pH 7 buffer, sodium citrate concentration 40 g per 100 ml), the cobalt in which has been removed previously by extraction (20 ml of buffer solution per 100 ml of sample solution), and the distilled water.Stir the mixture until the salts are dissolved. Determination of Cobalt Transfer three 100-ml portions of the sample solution (or smaller portions when a large amount of cobalt is present) into separating funnels. Then introduce 5 ml of distilled water into one of the funnels and 5ml of solutions containing known amounts of cobalt into the other two funnels. Transfer 5ml each of the citric acid buffer (pH 7) and nitroso-DMAP solutions into each funnel. [For iron(II1) salts and sodium citrate solution, no buffer solution was necessary, and with iron(II1) salts 10 ml of the nitroso-DMAP solution were added.] Mix the solutions, allow them to stand for 10 min and then shake them with 5 ml of 1,2-di- chloroethane for 5 min.Next wash the organic phases twice with 5 ml of 1 N potassium hydroxide solution and once with 1 + 2 hydrochloric acid solution and filter the organic phase through a dry filter-paper. Measure the absorbance of each organic phase in a cell of 50-mm path length at 456 nm against the reagent blank. The concentration of cobalt is determined by the standard additions method. The results obtained are given in Tables IX and X. Determination of Cobalt in Sea Water with Nitroso-DEAPZ Cobalt is one of the most interesting trace ions in sea water and is very difficult to deter- mine. Most of the methods that have been used necessitate pre-concentration, such as by co-crystallisation,~~~9 co-pre~ipitation,~~-~~ solvent extraction34 and use of chelating resins.35J6 These procedures require the use of large volumes of sample solution and are time con- suming, By using spectrophotometry following solvent extraction with nitroso-DEAP, about 0.1 pg 1-1 of cobalt can be determined.The procedure is as follows. Filter the sea water samples through a 0.45-pm membrane filter and put a 2-1 (or 1-1) portion of each into a separating funnel (about 2.3-1 capacity). To this, add 10 ml (or 5 ml) of sodium citrate solution (pH 7, concentration 40 g per 100 ml), the cobalt in which has been removed beforehand by extraction, and 20ml (or 10ml) of nitroso-DEAP solution (0.2% aqueous solution). Mix the solutions thoroughly and allow them to stand for 30 min, then add 10 ml (or 5 ml) of aqueous 10% EDTA solution and 20 ml (or 10 ml) of 1,2-dichloro- ethane.Shake the separating funnel for 10 min with a mechanical shaker. Next transfer the organic phase into a stoppered test-tube and back-extract the excess of the reagent,JuIy, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW TABLE IX DETERMINATION OF COBALT IN SODIUM AND POTASSIUM SALTS AND IN MIXTURES INVOLVING AMMONIA SOLUTION, HYDROCHLORIC ACID AND HYDROGEN CHLORIDE GAS Sample t A -l Type Compound Salts NaCl .. . . N+SO, .. . . NaNO, . . .. KC1 . . . . &SO, .. .. KNOs .. .. Sodium citrate Mixtures5 NH, . . NH, .. + ~Cl'(gas) + HCl'(gas) HCl .. + NHs* NaOH .. .. + HC1 (gas) HC1 . . .. + NaOH .. .. .. .. .. .. .. .. .. .. .. .. Grade* a e a e a e a e a e a e a e a e e a a a a Amount taken per 100 ml 31.7 g 28.6 g 30.2 g 27.9 g 28.9 g 28.9 g 26.6 g 28.4 g 14.8 g 14.6 g 25.3 g 27.6 g 38.5 g 35.8 g 43.3 ml 44.5 ml 7.3 ml 6.0 ml 20.1 g 41.3 ml 19.3 g Absorbancet 0.083 0.031 0.067 0.004 0.037 0.012 0.070 0.054 0.050 0.269 0.002 0.021 0.349 0.270 0.279 0.036 0.133 0.149 0.177 Cobalt content, % 3.1 x 10-7 1.7 x 10-7 2.8 x 10-7 1.7 x 10-7 3.1 x 10-7 2.3 x 10-7 4.6 x 10-7 - 7.3 x 10-8 2.1 x 10-6 8.7 x lo-* 1.1 x 10-6 1.0 x 10-6 7.1 x 10-7: 9.0 x 10-8: 1.5 x 10-8 - 507 7.7 x 10-7 8.0 x 10-8: * a and e denote analytical-reagent grade and extra-pure reagent, respectively. t Obtained by using the sample solution to which cobalt was not added.Reference, reagent blank. S In each instance, the first compound mentioned was neutralised with the second. 1 % miv. and the chelates of other metals, successively with three 5-ml portions of 1 + 2 hydrochloric acid, one 5-ml portion of 1 M potassium hydroxide solution and one 5-ml portion of 1 + 2 hydrochloric acid.Filter the organic phase through a dry filter-paper and measure the absorbance at 462 nm in a cell of 50-mm path length. Obtain the reagent blank by adding EDTA solution to another portion of sample before the sodium citrate solution. With sea water samples to which concentrated hydrochloric acid has been added (1 ml per 1 1 of TABLE X DETERMINATION OF COBALT IN IRON(III) SALTS Sample Salt Amount iakenj Cobalt Grade* g per 100 ml Absorbance? content, yo Fe2(S0,),(NH4),S0,.24H,0 . . a (i) 4.062 4.835 10.30: a (ii) 2.502 4.709 a (iii) 1.022 e (i) 1.6605 Fe(NO,),.SH,O . . .. . . a (i) 2.1155 FeCl,.6H20 .. . . . . a (i) 0.3405 e (i) 0.090§ 0.149 0.172 0.340 0.247 0.489 0.297 0.105 0.233 0.323 0.245 3.5 x 10-8 3.4 x 10-6 3.1 x 9.0 x 10-6 9.2 x 3.9 x 10-6 5.9 x 10-5 2.6 x 10-5 4.5 x 10-4 1.3 x 10-3 * a and e denote analytical-reagent grade and extra-pure reagent, respectively, and (i), (ii) and (iii) t Obtained by using the sample solution to which cobalt was not added. $ Twenty millilitres of the nitroso-DMAP solution were added. S Twenty millilitres of sample solutions were used and 2 ml of the nitroso-DMAP solution added. different suppliers.508 T ~ E I AND MOTOMIZU : PROPERTIES AND USES OF Analyst, Vol. 101 sea water) , wash the membrane filter by filtering 500 ml of 0.01 M hydrochloric acid solution before filtering the sea water, and neutralise the sea water sample with about 4 ml (or 2 ml) of 1 + 2 ammonia -water (optimum pH 5.5-7.5).When unfiltered sea water samples are used, the organic phase is withdrawn after shaking and centrifuged at about 2 000 rev min-I for 5 min before being placed in the stoppered test-tube. Sample" Seashore, May 26th, 1972t$ Seashore, June 14th, 1972t: Seashore, June 26th, 1972t Offshore, July 19th, 1972t: Same sample, untreated . . Same sample, filtered only: Same samplet .. TABLE XI COBALT CONTENT OF SEA WATER Volume taken/l .. 2 .. 2 . . 2 . . 2 . . 1 . . 1 .. 1 Absorbance 0.133 f 0.003 0.096 f 0.005 0.117 f 0.004 0.121 0.272 f 0.014 0.230 0.240 Cobalt found/pg 1-1 0.102 f 0.003 0.071 f. 0.004 0.089 f 0.004 0.092 0.155 f 0.008 0.139 0.144 * Samples taken at Shibukawa, Okayama Prefecture, Japan.t Samples contained 1 ml of concentrated hydrochloric acid per litre, and 0.009 pg ml-l of cobalt : Samples were filtered through a membrane filter. was subtracted from the value obtained from the calibration graph. A calibration graph was constructed by using sodium chloride solution (35.2 g l-l), the cobalt in which had been removed beforehand by extraction. The results obtained by use of the proposed method are given in Table XI. The reproducibility was sufficient for the determination of trace amounts of cobalt in sea water samples when 1-1 or 2-1 samples were used (Table XII). TABLE XI1 REPRODUCIBILITY OF ABSORBANCE OF COBALT IN SEA WATER Ten determinations. 2-1 sample 1-1 sample Mean absorbance . . .. . . 0.096 0.272 Standard deviation .. .. .. 0.004 0.008 Relative standard deviation . . 4% 3% Determination of Cobalt in Uranium Oxide (U308), Pure Uranium and a Uranyl Salt3' Cobalt is one of the most undesirable impurities in the fuel and materials of nuclear reactors because of its large cross-section of neutron absorption. The cobalt in a sample of uranium has been determined spectrophotometrically by use of a variety of method^.^-^^ These methods, however, are not sufficiently sensitive to determine micro-amounts of cobalt in uranium samples. By means of a solvent-extraction - spectrophotometric method using nitroso-DMAP, cobalt in samples containing more than 0.01 p.p.m. can be determined. The procedures are as follows. Preparation of Sample Solution Weigh the required amount of sample (uranium oxide or pure uranium) into a 50-ml beaker.Add 4 ml of concentrated nitric acid (sp. gr. 1.42) and dissolve the solid by heating the mixture. Following dissolution, evaporate the liquid nearly to dryness, dissolve the residue in distilled water and dilute the solution to the required volume with distilled water. A sample of a uranyl salt is dissolved in 0.1 N nitric acid solution and used without further treatment. Procedure I, for Samples Containing More Than 5 p.p.m. of Cobalt Transfer up to 15 ml of the sample solution (less than 40 pg of cobalt) into a 25-ml cali- brated flask. To this solution add 2.5ml of buffer solution A (citric acid buffer solution,July, 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW 509 2 M, pH 5.3), mix the solutions and allow the mixture to stand for 10 min.Then add 2 ml of nitroso-DMAP solution (0.2%), again mix and allow to stand for 10 min. Add 5ml of 1 + 1 hydrochloric acid and dilute to the mark with water. Measure the absorbance at 530 nm in a cell of l-cm path length. Procedure 11, for Samples Containing 0.5-5 p.p.m. of Cobalt Transfer up to 10 ml of the sample solution (less than 4 pg of cobalt) by pipette into a 25-ml, glass-stoppered test-tube, add distilled water and dilute the solution to 10 ml. Add 2 ml of buffer solution A, mix thoroughly and allow the mixture to stand for 10 min. Next add 1 ml of nitroso-DMAP solution and again mix and allow to stand for 10 min. Into this tube, transfer 5 ml of 1,2-dichloroethane, then shake the tube for 1 min by hand.Back- extract the excess of the reagent and other metal chelates with 1 + 2 hydrochloric acid and 1 N sodium hydroxide solution. Filter the organic phase through a dry filter-paper and measure the absorbance at 456 nm. Procedure 111, for Samples Containing 0.01-0.5 p.p.m. of Cobalt In this method, ten-fold concentration was achieved. The absorbances of the cobalt complex in 1,2-dichloroethane were measured in a cell of either 10-mm path length [Pro- cedure III(a)] or 50-mm path length [Procedure III(b)]. Transfer up to 50 ml of the sample solution, by pipette, into a 100-ml, glass-stoppered test-tube or separating funnel, and dilute to 50 ml with distilled water if necessary. To this solution add 10 ml of sodium citrate solution (trisodium citrate dihydrate, 40 g per 100 ml), the cobalt in which has been removed beforehand by extraction, mix thoroughly and allow the mixture to stand for 10 min.Add 5 ml of nitroso-DMAP solution, again mix and allow to stand for 10 min. Transfer 5 ml of 1,2-dichloroethane to the mixture and shake it for 10 min with a mechanical shaker, then back-extract the excess of the reagent and the chelates of other metals with hydrochloric acid and sodium hydroxide solutions. Filter the organic phase through a dry filter-paper. Measure the absorbance of the filtrate at 456 nm in a glass cell of either 10-mm path length [Procedure III(a)] or 50-mm path length [Procedure III(b)]. TABLE XI11 DETERMINATION OF COBALT IN URANIUM OXIDE AND PURE URANIUM Sample Amount of cobalt, p.p.rri. solution -----Tz Sample Sample solution Procedure taken/ml Absorbance* in U30, JAERI-U2 1.912 g per 50 ml 0.994 0 g per 50 ml 0.491 0 g per 100 ml 0.501 2 g per 100 in1 JAERI-U1 (No.4) 4.935 g per 100 ml 5.132 g per 50 ml 5.039 g per 100 ml JAERI-Ul (No. 5) 5.052 g per 100 ml 5.118 g per 100 ml 4.756 g per 100 ml 5.335 g per 100 ml 0.933 g per 50 ml 0.904 g per 50 ml 1.754 g per 50 ml JAERI-U4 (pure uranium) * Reference, reagent blank. I I1 111 (a) I11 (b) I1 111 (a) I11 (b) I11 (b) I11 (b) I11 (b) I11 (b) I11 (b) I11 (b) I11 (b) 6 10 5 10 20 5 10 15 5 10 5 10 5 10 25 20 50 20 50 25 50 50 50 0.030 f 0.001 0.054 f- 0.000 0.147 f 0.003 0.078 f 0.001 0.152 f- 0.000 0.183 f 0.003 0.367 f 0.001 0.554 0.049 f- 0.001 0.099 f- 0.001 0.109 & 0.001 0.216 f- 0.004 0.255 f 0.001 0.518 f 0.005 0.054 0.042 f 0.003 0.076 0.003 f 0.002 0.069 0.040 0.010 0.006 0.013 7.1 f 0.0 6.6 0.0 6.4 f 0.1 6.4 f 0.0 6.4 f 0.0 6.4 f 0.1 6.4 f 0.1 6.5 0.85 f 0.01 0.87 f 0.01 0.84 f 0.00 0.85 f 0.01 0.89 f 0.00 0.91 0.01 0.04 0.04 f 0.01 0.03 0.03 f 0.00 0.03 0.03 - - - 8.4 -& 0.0 7.8 f 0.0 7.5 f 0.1 7.5 f 0.0 7.5 & 0.0 7.5 f 0.0 7.5 f 0.1 7.6 0.99 f 0.01 1.02 & 0.01 0.98 & 0.00 0.99 f 0.01 1.04 & 0.00 1.06 f 0.02 0.04 0.04 &- 0.01 0.03 0.04 f 0.01 0.03 0.03 0.009 0.007 0.007510 Analyst, VoZ.101 Determination of Cobalt The results obtained by use of the procedures I, 11, III(a) and III(b), for micro- and trace amounts of cobalt in samples such as JAERI-U2, JAERI-U4 (pure uranium) anduranium nitrate, are given in Tables XI11 and XIV.T ~ E I AND MOTOMIZU: PROPERTIES AND USES OF TABLE XIV DETERMINATION OF COBALT IN URANYL NITRATE [PROCEDURE III(b)] Supplier Grade* Sample takenlg Absorbance? Amount of cobalt, p.p.m. a 0.001 A 3.754 0.005 5.005 0.008 0.001 B a 2.513 0.080 0.028 2.485 0.080 0.029 5.026 0.151 0.026 4.966 0.155 0.028 * a, Analytical-reagent grade. t Reference, reagent blank. Conclusion Nitrosonaphthol and nitrosophenol derivatives are well known to be sensitive to, and specific for, cobalt ; twenty-five of their derivatives were synthesised by the authors and the potential of each for the colorimetric determination of cobalt was examined. Among these compounds, the cobalt complexes of nitroso-DMAP and nitroso-DEAP were found to have the highest molar absorptivities (about 6 x lo4) and these reagents were used successfully as colorimetric reagents for the determination of a minute amount of cobalt in pure nickel salts, various pure chemicals, iron and steel, sea water and uranium.Nitroso-DMAP and nitroso-DEAP are not only specific for cobalt, but also the interference from co-existing ions is readily eliminated by simple procedures, such as a masking reaction with citrate buffer solution and an extraction procedure. The synthesis of nitroso-DMAP and nitroso-DEAP is very simple and the crystals of the reagents are easily obtained by recrystallisation from solution in hydrochloric acid as the hydrochlorides. The crystals are stable for at least 2 years. The reagents are soluble in 0.01 M hydrochloric acid, and in the determination of cobalt they are used in aqueous solution or with an extraction procedure involving the use of an organic solvent.A higher molar absorptivity than those of cobalt complexes of nitroso-DMAP and nitroso- DEAP was seldom found among the other organic reagents. The cobalt complexes of some pyridylazo compounds are known to have higher molar absorptivities, viz., 4-(2-pyridyl- azo)resorcinol ( E = 6.2 x lo4 1 mol-l cm-l at 530 nm),45 4-(5-chloro-2-pyridylazo)-1,3-di- aminobenzene (E = 1.13 x lo5 1 mol-l cm-l at 570 nm)46 and N-methylanabasineazodi- ethylaminophenol (E = 7.8 x lo4 1 mol-l cm-l at 440 nm).47 Also, the cobalt complex of Chromazurol S has a molar absorptivity of 1.09 x lo5 1 mol-l cm-I at 654 nm in the presence of hydroxydodecyltrimethylammonium bromide.** These reagents are sensitive to, but not specific for, cobalt.As they can also react with co-existing ions, many pre-treatments are necessary in order to eliminate the disturbance caused by the co-existing ion. Nitroso-DMAP and nitroso-DEAP are recommended as colorimetric reagents for cobalt because they are highly sensitive to, and specific for, cobalt and little pre-treatment is neces- sary in order to eliminate the effects of co-existing ions. A very small amount of cobalt in various materials can be determined by use of these reagents, down to the parts per billion ( lo9) level. References 1. 2. 3. 4. 5. 6. 7. Ilinski, M., and von Knorre, G., Ber. Dt. Chem. Ges., 1885, 18, 699. TBei, K., and Motomizu, S., Nippon Kagaku Zasshi, 1971, 92, 92. Korenaga. T., Motomizu, S., and TBei, K., Nippon Kagaku Kaishi, 1972, 2445.TBei, K., and Motomizu, S., Japan Analyst, 1973, 22, 1079. Witt, 0. N., and Kaufmann, H., Ber. Dt. Chem. Ges., 1891, 24, 3157. Henriques, R., and Ilinski, M., Bey. Dt. Chem. Ges., 1885, 18, 704. Kostanecki, V., Ber. Dt. Chem. Ges., 1889, 22, 1342.8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 1976 COLORIMETRIC REAGENTS FOR COBALT. A REVIEW 51 I Lagodzinski, K., and Hardine, D., Ber. Dt. Chem. Ges., 1894, 27, 3075. Shimura, H., A . Rep. Wakayama Prefectural Inst. Publ. Hlth, 1959, 11, 1. M(ihlau, R., Ber. Dt. Chem. Ges., 1892, 25, 1055. Motomizu, S., Analytica Chim. Acta, 1971, 56, 415. Motomizu, S., Talanta, 1974, 21, 654.Young, R. S., and Hall, A. J., Ind. Engng Chem., Analyt. Edn, 1946, 18, 264. Yokosuga, S., Japan Analyst, 1967, 6, 690. Snell, F. D., and Snell, C. T., “Colorimetric Methods of Analysis,” Third Edition, D. Van Nostrand Motomizu, S., Japan Analyst, 1973, 22, 695. Motomizu, S., Nippon Nagaku Zasshi, 1971, 92, 726. Koch, K. H., Ohls, K., Sevastiani, E., and Riemer, G., 2. Analyt. Chem., 1970, 249, 307. Needleman, M., Analyt. Chem., 1966, 38, 915. Kawahata, M., Mochizuki, H., and Misaki, T., Japan Analyst, 1960, 9, 1023. Boulin, R., and Leblond, A. M., Analytica Chim. Acta, 1971, 56, 45. Motomizu, S.. Japan Analyst, 1971, 20, 1607. Motomizu, S., Analyst, 1972, 97, 986. Marczenko, Z., Mikrochim. Acta, 1965, 281. Babko, A. K., Kuz’min, N. M., Listskaya, G. S., Ourutskii, M. I., and Freger, S. V., Ukr. Khinz. KO, R., and Anderson, P., Analyt. Chem., 1969, 41, 177. Motomizu, S., Analytica Chim. Acta, 1973, 64, 217. Weiss, H. W., and Reed, J. A., J . Mar. Res., 1960, 18, 185. Riley, J. P., and Topping, G., Analytica Chim. Acta, 1969, 44, 234. Ishibashi, M., Rec. Oceanogr. Wks Japan, 1953, 1, 88. Thompson, T. G., and Laevastu, T., J . Mar. Res.. 1960, 18, 189. Forster, W., and Zeitlin, H., Analytica Chim. Acta, 1966, 34, 211. Krishnamoorthy, T. M., and Viswanathan, R., Indian J . Chem., 1969, 6, 169. Armitage, B., and Zeitlin, H., Analytica Chim. Acta, 1971, 53, 47. Riley, J. P., and Taylor, D., Analytica Chim. Acta, 1968, 40, 479. Abdullah, M. I., and Royle, L. G., Analytica Chim. Acta, 1972, 58, 283. Motomizu, S., Analyst, 1975, 100, 39. Bane, R. W., in Rodden, C. J., Editor, “Analytical Chemistry of the Manhattan Project,” McGraw- Chilton, J. M., Rep. Congr. U S . Atom. Energy Commn, AECD-3607, 1953. Bane, R. W., and Grimes, W. R., in Rodden, C. J., Editor, “Analytical Chemistry of the Manhattan Project,” McGraw-Hill Publishing Co., New York, 1950, p. 415. Motojima, K., and Tamura, N., Analytica Chim. Acta, 1969, 45, 327. Suzuki, M., and Takeuchi, T., Japan Analyst, 1960, 9, 179. “Analysis of Uranium Oxide,” JAERI 4053, The Committee on Analytical Chemistry of Nuclear Hashitani, H., Yoshida, H., and Adachi, T., Bunseki Kagaku, 1975, 24, 452. Okochi, H., Japan Analyst, 1972, 21, 51. Shibata, S., Furukawa, M., Ishiguro, Y., and Sasaki, S., Analytica Chim. Acta, 1971, 55, 231. Martirosov, A. E., Talipov, S. T., and Dzhiyanbaeva, R. K., Nauch. Trudy Tashkent Gos. Univ., Shijo, Y., Takeuchi, T., and Yoshizawa, S., Japan Analyst, 1969, 18, 204. Co. Inc., New York, 1958, p. 355. Zh., 1967, 33, 828. Hill Publishing Co., New York, 1950, p. 430. Fuels and Reactor Material, Japan Atomic Energy Research Institute, 1970, p. 90. 1968, 323, 74. Received December loth, 1975 Accepted December 30th, 1975

ISSN:0003-2654    

DOI:10.1039/AN9760100497

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

512 Analyst, July, 1976, Vol. 101, $9. 512-515 Analysis of Steroids Part XXVII.* Oestrogens in Oily Injections in the Presence of 4- Ene-3-ketosteroidst Difference Spectrophotometric Determination of Sandor Gorog Chemical Works, Gedeon Rich.ter Ltd., Gyomroi ut 21, H-1475 Budapest, Hungary A difference spectrophotometric method is described for the determination of 2.5-5 mg ml-1 amounts of oestrogens (esters of oestrone and oestradiol) in oily injections in the presence of a large excess of 4-ene-3-ketosteroids. The method is based on a bathochromic shift of the ultraviolet spectrum of the extracts of the samples in methanol in alkaline media. Any interference caused by co-extracted oil or by unsaturated ketosteroids is eliminated by careful choice of pH settings (9.2 for the reference solution by using borate buffer and the test solution 0.2 N in sodium hydroxide) and reduction with sodium borohydride, respectively.The difference between the results found and the label claims for four formulations was less than 2% and the relative standard deviations ranged between 1.1 and 1.7 "/o. In addition to the general problems encountered in the analysis of oily solutions the spectro- photometric determination of oestrogens in oily injections is made even more difficult by the fact that these injections are usually administered in low doses and accompanied by a large excess of unsaturated ketosteroids (progestogens or androgens). Although the im- portance of chromatographic methods (mainly gas-chromatographicl-3, in this field, has greatly increased, optical methods are more often used for the assay of the oestrogenic components of such injections.Of the optical methods the classical colorimetric procedure^^,^ and their modernised developments6-8 are still most often used. Much less attention has been paid to the simplest possibility, namely determination on the basis of the natural ultraviolet absorption of the oestrogen. A rare example is the ultraviolet difference spectrophotometric method of USP XVII-XIX4-11 for the determination of oestradiol valerate in oily injections, which is based on the bathochromic displacement of the spectrum of the phenolic ring A in an alkaline medium. James12 has pointed out that this method can only be applied if the oestrogen content of the injection exceeds 10 mg ml-l and unsaturated ketosteroids are not present.Thus, in its original form, the USP method cannot be applied to the great majority of practical pro- blems. The present paper is an attempt to extend the field of application of the USP method to almost all kinds of oestrogenic preparation intended for injection. This finding has been confirmed in our laboratory. Experimental Reagents All materials and solvents were analytical-reagent grade and were used without further purification. Sodium borohydride. Methanol. Ethyl methyl ketone. Sodium hydroxide solution, 1 N -@yo. Boric acid solution, 0.1 M. Apparatus A Spektromom 202 spectrophotometer (MOM, Budapest, Hungary) was used in order to * For Part XXVI of this series, see J . Chromat., 1976, 118, 411. t Presented at the 26th Pittsburgh Conference, Cleveland, Ohio, March 3rd to 7th, 1975.GOROG 513 obtain the absorbance readings while the spectra were recorded with a Pye Unicam SP1800 recording spectrophotometer.Formulations Investigated sunflower oil (Oleurn helianti). The formulations investigated are listed in Table I. The oily injections were prepared using Procedure A 2-ml injection solution is cautiously stirred with 50 ml of methanol for 5 min. The methanol layer is decanted through a filter, care being taken that the bulk of the oil does not come into contact with the filter-paper. This extraction is then repeated with two further 20-ml portions of methanol stirred for 2-min each. (Being a non-oily injection, Limovanil emulsion is directly dissolved in the methanol.) A 1-ml volume of 1 N sodium hydroxide solution and 0.1 g of sodium borohydride are added to the combined methanolic extracts and the mixture is refluxed for 5 min.Following the addition of 1 ml of ethyl methyl ketone the solution is next refluxed for a further 2 min; after cooling it is diluted with methanol to 100 ml. Water (5 ml) and 5 ml of 0.1 M boric acid solution are added to a 25-ml aliquot of this stock solution and the volume of the mixture is adjusted to 50 ml with methanol. The resulting solution, with a pH of about 9.2, is placed in the reference cell. The test solution is prepared in a similar manner from the same stock solution, the only difference being that instead of 5 ml of water, 5 ml of 1 N sodium hydroxide solution is added.The difference absorbance is then measured at a wavelength of 300nm. For injections with an oestrogen content of 5mgml-1 or more, 1-cm cells are used, whereas for lower concentrations, 2-cm cells are necessary. The oestrogen content of the sample is calculated on the basis of the absorbances of standard solutions run simultaneously. Results and Discussion As was mentioned above the basis of the difference spectrophotometric assay of oestrogens is the bathochromic shift of their spectra in strongly alkaline media. The absorption maxi- mum of oestradiol, with an undissociated phenolic hydroxyl group (in 80% V/V methanol below pH 9.5), occurs at 280 nm (A:% = 75) while that of the ionised form (above pH 13) occurs at 298nm (Aig = 104). The difference spectrum obtained by placing the former solution in the reference cell and the latter one in the sample cell can be seen in graph A of Fig.1. Graph B is the difference spectrum of Ambosex injection obtained by use of the USP method for oestradiol valerate.ll It can be seen that a high background appears with a broad band at 370 nm, which is too high to be corrected for at the maximum of the difference spectrum. On examining the reasons for this high background we have found that inappropriate pH values have been selected for both sample and reference solutions. In a difference spectro- photometric method intended to eliminate a background absorption the pH values of the solutions must be selected as close to each other as possible, the only prerequisite being that a completely dissociated form should exist in one solution and a completely undissociated form in the 0ther.1~ As oestrogens are very weak acids, they begin to dissociate at about pH 9.5 and dissociation is complete at an alkali concentration of 0.2 N.In the USP method the pH of the reference solution is below 2 and the alkali concentration of the test solution is about 0.6 N. As the spectrum of the oestrogens does not change between pH 2 and 9.5, nor between alkali concentrations of 0.2 and 0.6 N, whereas the non-specific absorptions origin- ating from the accompanying materials co-extracted from the oil do, the effect of the latter can be eliminated by adopting a pH of 9.2 for the reference cell and a sodium hydroxide con- centration of 0.2 N in the sample cell ; any spectrophotometrically active acidic impurities with a pK value of less than 8 are already ionised in the reference cell and thus do not interfere.The yellow colour (absorbance maximum at 370 nm) of the solutions that is obtained when analysing formulations containing 4-ene-3-ketosteroids by use of the USP method is supposed to be due to autoxidation of the steroid, in the strongly alkaline medium used, to 4-ene-3,6-514 GOROG: ANALYSIS OF STEROIDS. PART XXVII Analyst, Vol. 101 -0.1 ' I I 1 I I I 300 340 380 420 Wavelength/nm Fig. 1. Difference spectra: graph A, 3 mg per 100 ml of oestradiol solution in 80% V/V methanol, reference solution pH 9.2, test solution 0.2 N sodium hydroxide solution; B, Ambosex injection, reference and test solu- tions prepared according to the USP method; C, Ambosex injection, reference and test solutions prepared according to the proposed method.dione, which exists in the enolate form (6-hydroxy-4,6-diene-3-one) at this high pH and shows an absorption maximum at the same wavelength as the 4-ene-3-keto compound.14-16 This supposition has been proved, and at the same time the problem solved, by reducing the 3-keto group with sodium borohydride prior to mea~urement,l~-~l as the reduced species formed (4-ene-3-01) is no longer sensitive to atmospheric oxygen. The reduction is carried out by boiling the methanolic extract with a sodium hydroxide - sodium borohydride reagent, as a result of which the esterified 3-hydroxy groups are also hydrolysed. The excess of sodium borohydride is made to react with ethyl methyl ketone.22 Graph C of Fig.1 shows the difference spectrum obtained by using the above described modifications to the USP method. The interference can be seen to have been eliminated and the graph corresponds, in both qualitative and quantitative respects, to the difference spectrum of pure oestradiol (graph A). The results obtained by use of the proposed method are summarised in Table I. TABLE I ANALYSIS OF VARIOUS OESTROGENS IN INJECTIONS Oestrogenic Preparation active ingredient Limovanilt Oestradiol benzoate Limovanilt Oestradiol benzoate Ambosext Oestradiol benzoate Hogivalt Oestrone acetate (oily injection) (aqueous emulsion) Oestradiol phenyl- propionate Label concen- tration/ mg ml-I 2.5 2.5 4.0 5.0 Relative Found, standard yo of label deviation*, 98.2 1.4 claim % 99.5 1.1 100.2: 1.7 102.0 1.4 * Calculated from six parallel runs.t Richter trade names. Sum of the two oestrogens referred to a similarly composed standard. 4-Ene-3- ketos teroid active ingredient1 mg ml-1 Progesterone, 12.6 Progesterone, 12.5 Testosterone esters, 100 - Although the method gives no indication of the stabilities of the solutions involved, it has proved suitable for the rapid routine assay of oestrogenic injection preparations.July, I 9 76 GOROG: ANALYSIS OF STEROIDS. PART XXVII 515 The author is grateful to Mrs. M. Markus and Mrs. M. KapAs for their technical assistance. 1. 2. 3. 4. 6. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. References Talmage, J . M., Penner, M. H., and Geller, M., J .Pharm. Sci., 1965, 54, 1194. Moretti, G., Cavina, G., and Sardi di Valverde, J., J. Chromat., 1969, 40, 410. Cavina, G., Moretti, G., and Siniscalchi, P., J. Chromat., 1970, 47, 186. Haenni, E. O., J . Am. Pharm. Ass., Scient. Edn, 1950, 39, 544. “British Pharmacopoeia 1973,” The Pharmaceutical Press, London, 1973, p. 330. “Pharmacopoeia Helvetica VI. Deutsche Ausgabe,” Band 111, Verlag Eidgenossische Druckzachen Sjostrom, E., and Nykanen, L., J . Am. Pharm. Ass., Scient. Edn, 1957, 46, 321. UrbAnyi, T., and Rehm, C. R., J. Pharm. Sci., 1966, 55, 601. “United States Pharmacopeia XVII,” Mack Publishing Co., Easton, Pa., 1965, p. 242. “United States Pharmacopeia XVIII,” Mack Publishing Co., Easton, Pa., 1970, p. 242. “United States Pharmacopeia XIX,” USP Convention Inc., Rockville, Md., 1976, p. 181. James, T., J . Ass. Off. AnaZyt. Chern., 1971, 54, 1192. Gorog, S.. “Proceedings of the Second Conference on Applied Physical Chemistry, VeszprCm,” Pesez, M., Poirier, P., and Bartos, J., “Pratique de I’Analyse Organique Colorimetrique,” Masson, Mayer, A. S., J. Org. Chem., 1955, 20, 1240. Langenbach, R. J., and Knoche, H. W., Steroids, 1968, 11, 123. Gorog, S., Steroids, 1968, 11, 93. Gorog, S., J. Pharm. Sci., 1968, 57, 1737. Gorog, S., and CsizCr, I?., Acta Chim. Hung., 1970, 65, 41. Chafetz, L., Tsilifonis, D. C., and Riedl, J. M., J. Pharm. Sci., 1972, 61, 148. Chafetz, L., Tsilifonis, D. C., and Moran, C., J. Pharm. Sci., 1974, 63, 1771. Gorog, S., J. Phamm. Pharmac., 1969, 21, 46s. und Materialzentrale, Bern, 1971, p. 338. Volume 1, Akad6miai Kiad6, Budapest, 1971, p. 323. Paris, 1966, p. 275. NOTE-References 17, 18, 19 and 22 are to Parts VII, VIII, XI and XI1 of this series, respectively. Received January 26th, 1976 Accepted February 23rd, 1976

ISSN:0003-2654    

DOI:10.1039/AN9760100512

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

516 Analyst, J d y , 1976, Vol. 101, pp. 516-518 Determination of Aluminium in Iron Ore and Iron Ore Sinter by a Complexometric Method Samaresh Banerjee and R. K. Dutta Research and Control Laboratory, Durgapuv Steel Plant, Durgapur-3, West Bengal, India A complexometric method for the determination of aluminium in iron ore and sinter products has been developed. Iron, manganese, vanadium, etc. , are complexed with mercaptoacetic acid, and aluminium and other elements such as titanium, if present, are precipitated as R,O, with hexamethylene- tetramine (hexamine). The precipitate of R,O, is dissolved in hydrochloric acid and complexed with EDTA. The excess of EDTA is titrated with standard lead solution using xylenol orange as indicator. The EDTA bound to the aluminium is released by boiling with ammonium fluoride and back- titrated with standard lead solution with xylenol orange as indicator and hexamine buffer.The method eliminates the usual solvent extraction pro- cedure and aluminium is separated from iron, manganese, vanadium, calcium and magnesium, etc., in a single step; it takes about 1-2 h and is suitable for routine analysis. Of all the common elements in iron ore and sinter products, aluminium is probably the most difficult to determine accurately because of interference by other elements present in the ore. The standard gravimetric methods are not suitable for routine analysis. During recent years, complexometric method~l-~ have attracted much attention. With iron ore, the major difficulty arises from the high percentage of iron present in the ore and even in complexometric procedures the iron has been removed by a preliminary extraction with diethyl ether or isobutyl methyl ketone.g Although the bulk of the iron can be removed by solvent extraction, this step makes the method both lengthy and expensive to operate and it would thus have limited scope in plant control laboratories where a large number of iron ore and sinter products have to be analysed within the shortest possible time.We have previously used mercaptoacetic acid for complexing the iron present when deter- mining titanium and aluminium in bauxite, ilmenite and ferrotitanium' by a gravimetric procedure. A method has now been developed for the determination of aluminium in iron ore and iron ore sinter in which iron, manganese and vanadium (if present) are complexed with mercaptoacetic acid and R,O, is precipitated with hexamethylenetetramine (hexamine).The precipitate of R?O, is dissolved in hydrochloric acid and boiled with excess of EDTA. The excess of EDTA is back-titrated with a standard lead solution using hexamine buffer and xylenol orange as indicator. The EDTA bound to aluminium is then released by boiling with ammonium fluoride and titrated with standard lead solution. Experimental Reagents Mereaptoacetic acid (1 + 1 V/V). Ammonium juoride solution, 10% m/V. Neutralise the solution with ammonia to methyl red indicator and store in a polythene bottle. Hexamine. Xylenol orange solution, 0.1% m/V in water. Prepare freshly every week. Washing sol.ution. Mix ammonium chloride (2% m/V) and mercaptoacetic acid (2% m/V) solutions in equal proportions and add ammonia solution dropwise until a faint smell of ammonia persists.Prepare freshly every week. Standard lead solution, 0.01 M. Weigh 2.0721 g of lead (purity 99.99%) into a 125-ml Erlenmeyer flask. Add 5 ml of water followed by 5 ml of concentrated nitric acid. Cover the flask and boil gently. Add 2-ml increments of water and heat until the dissolution is complete. Add 50 ml of water and boil gently for 2 min, cool, add 1 drop of methyl red and add sodium hydroxide (5% m/V) until the pink colour is just discharged. Transfer theBANERJEE AND DUTTA 517 solution quantitatively into a 1-1 calibrated flask, add 2-3 drops of concentrated nitric acid and make up to volume with distilled water.Standard EDTA solution, 0.01 prz. Dissolve 3.72 g of disodium dihydrogen ethylenediamine- tetraacetate dihydrate (EDTA) in water and dilute to 1 1 with distilled water. Store in a polythene bottle. Procedure Transfer 0.5 g of the prepared sample into a 400-ml beaker, add 15 ml of hydrochloric acid (sp. gr. 1.19) and heat below boiling-point until the ore starts to dissolve, then add 5 ml of nitric acid (sp. gr. 1.42). Evaporate the solution to dryness on a hot-plate and dry the residue by heating it for 15 min. Dissolve the dried residue in hydrochloric acid (1 + 1). Boil for 1 min, then filter to remove silica and retain the filtrate. Transfer the filter-paper containing the insoluble residue to a platinum crucible, dry and then bum the paper at a low temperature and ignite the residue at 950-1 000 "C.Allow the crucible to cool, moisten the contents with a few drops of sulphuric acid (1 + 1) and 5-10 ml of hydrofluoric acid (sp. gr. 1.13) and evaporate on a hot-plate. Continue to heat the solution until all traces of sulphur dioxide are removed. Cool, add about 3 g of potassium pyrosulphate, fuse the residue and allow to cool. Place the crucible in a 250-ml beaker, add warm water and a small volume of hydrochloric acid (1 + 1) and heat gently until dissolution of the melt is complete. Remove the crucible, rinse it with water and add the solution to the original filtrate from the dissolution of the sample. Transfer this solution into a 250-ml calibrated flask and make up to volume with distilled water.Transfer by pipette a suitable aliquot of the sample solution (150, 100, 50 or 25ml for aluminium contents of 0.1, 1, 3 or 5%, respectively) into a 400-ml beaker, add 1 g of am- monium chloride and heat to boiling. Add 15-20 ml of mercaptoacetic acid and stir with a glass rod. When the colour of the solution has discharged, add ammonia solution dropwise until the pink colour of the iron - mercaptoacetic acid complex in ammoniacal solution appears. Add 2 g of hexamine and some filter-paper pulp, boil for 1 min and then gently for a further 2 min and filter through a Whatman No. 41 filter-paper. Wash the precipitate with the washing solution until the filtrate is free from pink colour and discard the filtrate. Heat 5 ml of hydrochloric acid (sp. gr. 1.19) to boiling in the beaker in which precipitation took place, pour the acid dropwise over the filter-paper and collect the filtrate in a 500-ml Erlenmeyer flask.Wash the filter-paper several times with hot distilled water and add the washings to the filtrate. Return the filter-paper into the beaker and macerate it to a pulpy mass using a glass rod. Add 10 ml of hydrochloric acid (1 + l), boil for 1 min, filter through a Whatman No. 41 filter-paper and collect the filtrate in the Erlenmeyer flask. Wash the beaker and filter-paper several times with hot distilled water. Add an excess of 0.01 M EDTA to the filtrate and neutralise the solution with ammonia using methyl red as indicator. Add about 2 g of hexamine and boil gently for 3 4 min. Cool and titrate the excess of EDTA with standard lead solution using xylenol orange as indicator.The volume of lead solution used need not be recorded. Add 10 ml of ammonium fluoride, boil for 3 4 min and cool. Titrate with 0.01 M lead solution to the same end-point as in the first titration. The volume added in the second titration corresponds to the amount of aluminium present in the solution. Carry out a blank determination on the reagents in the absence of the sample. Calculate the aluminium content from the following equation : (V, - V2) x 0.000 27 x 100 m Al(%) = where Vl is the consumption of 0.01 M lead solution in the sample titration; V2 is the consump- tion of 0.01 M lead solution in the blank titration; m is the mass of sample present in the aliquot taken of the sample solution; and K = lOO/(lOO - A ) , A(%) being the moisture content of the sample.Results and Discussion Typical results for some standard iron ore samples are shown in Table I. In the present method, silica was removed by a single dehydration with hydrochloric acid and the method should be used for the determination of aluminium only. If both aluminium518 BANERJEE AND DUTTA and silica are to be determined, silica should be removed either by double dehydration with hydrochloric acid or by a single-stage dehydration with perchloric acid. If perchloric acid is used for dehydration of silica, the residue left after digestion with hydrofluoric acid should be fused with sodium hydrogen sulphate instead of potassium pyrosulphate. TABLE I ALUMINIUM CONTENT OF SOME STANDARD IRON ORE SAMPLES Aluminium, % Sample Riported Found Titanium, % Marcona ... . . . 0.35" 0.35 <0.01 0.33 0.66 2.33 1.74 3.48 3.82 Krivoj . . . . .. . . 0.65* 0.65 <0.01 Minette . . . . .. .. 2.38* 2.36 0.05 BCS 377 .. .. . . 1.80t 1.68 0.11 Iron ore sinter, BCS 303 . . 3.60t 3.51 0.18 BCS 302 .. .. . . 3.84t 3.80 0.21 * Average A1 content reported using IS0 gravimetric procedure.8 t A1 content reported on certificate. Solutions of synthetic iron ores having different percentages of aluminium were prepared. To these synthetic sample solutions, standard titanium solution (1 mg ml-1) was added in different proportions and the aluminium content was determined by the present method. It was observed that both the fluoroaluminium and fluorotitanium species released the corre- sponding equivalent amount of EDTA bound with both aluminium and titanium from the aluminium and titanium chelates.Thus, when analysing iron ore containing titanium, the titanium content must be determined separately by the colorimetric method and the figure for aluminium must be corrected for titanium (1 mg of titanium corresponds to 2.1 ml of the EDTA solution). We thank Sri G. Chatterjee, Chief Metallurgist, Research and Control Laboratory, for his interest and encouragement and Sri K. K. Mukhopadhyaya, General Superintendent, Durgapur Steel Plant, for encouragement and for permission to publish this paper. References 1. 2. 3. 4. 5. 6. 7. 8. International Standardisation Organisation, Draft prepared by Committee ISO/TC102/SC2, Vanninen, E., and Ringbom, A., Analytica Chim. Acta, 1955, 12, 308. Schwartzenbach, G., "Complexones," Uetikon Chemical Co., Zofingen, Switzerland, 1953. Sajo, I., A d a Chim. Hung., 1955, 6, 233. Nestoridis, A., Analytica Chim. Acta, 1970, 49, 335. Pfibil, R., Talanta, 1965, 12, 926. JIS M 8220, Japanese Industrial Standard Methods for the Determination of Aluminium Oxide Banerjee, S., and Dutta, R. K., Indian J. Technol., 1973, 11, 317, in Iron Ore, Japanese Standards Association, Tokyo, 1964. ISO/TClO2 (Ze-$j-')265E. Received Sefitember loth, 1975 Accepted January 20th, 1976

ISSN:0003-2654    

DOI:10.1039/AN9760100516

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

Analyst, Jab, 1976, Vol. 101, pp. 519-521 519 Spectrophotometric Studies on the Determination of 2,6 - D ic h I or0 p henol J. Liptak," J. Reiter and L. Toldy Research Institute for Pharmaceutical Chemistry, P.O. Box 82, Budapest 1325, Hungary Simple, rapid and quantitative analytical methods are described for the deterinination of 2,6-dichlorophenol in instances when an ether of the same phenol is present in the sample by using near-infrared and ultraviolet spectro- photometry. The mechanism of a generally valid N-alkylating reaction was established in kinetic studies by determination of the 2,6-dichlorophenol produced by the reaction. It has been reported1s2 that a new type of N-alkylating reaction occurs when aryl alkyl ethers are heated with primary or secondary amines, yielding the corresponding alkylamines and phenols, respectively : CI CI H3C--NANH + R - 0 9 c_f H3C-N n N-R + HO-@ U u CI CI 1 2 3 4 R = -CHZ-CHZ-CH~-CH~ The reaction mechanism was suggested on the basis of preparative and mass-spectrometric investigations.3~~ Nevertheless, whether the reaction was SN1 or SN2 in character remained to be decided.If an SN2 reaction takes place the reaction rate should depend on the molar concentrations of both [ l ] and [2], whereas if it is an SN1 reaction it should depend only on the concentration of [2]. In order to solve the problem the mode of reaction shown above was chosen as a model. To follow the reaction a rapid, selective and quantitative analytical method for determining one of the compounds was required. Experimental Reaction Procedure The N-alkylating reaction was carried out in thick-walled, sealed, glass tubes at 200 "C in a heating block.Three series of sealed test-tubes containing the starting materials, [l] and [2], in 0.5: 1, 1 : 1 and 2: 1 molar ratios, respectively, were heated, the amount of 2,6-dichlorophenyl butyl ether [2] being 0.01 mol in each instance. The results of pre- liminary experiments showed that the reaction mixture remained practically unchanged until the temperature reached 200 "C, so the time at which this temperature was achieved was considered to be the zero point of the reaction (4 min). Samples were taken from the three different series at the kinetic zero point and after 15, 30, 60, 120 and 720 min, and the concentration of [a] was determined.Determination of 2,6-Dichlorophenol by an Ultraviolet Method After cooling and opening the sealed tubes the reaction mixtures were dissolved in carbon tetrachloride to give a volume of 50 ml. A 5-ml volume of that solution was then extracted with three 10-ml portions of 0.1 N sodium hydroxide solution. The three aqueous layers were combined, centrifuged at 5 000 rev min-l in a laboratory centrifuge and, after adequate dilution with 0.1 N sodium hydroxide solution, assayed spectrophotometrically at 302 nm * Present address : Institute of Pharmacognosy, Semmelweis Medical University, UlMi ~t 26, 111, H-1085 Budapest, Hungary.520 LIPTAK, REITER AND TOLDY : SPECTROPHOTOMETRIC Analyst, V d . 101 using a Unicam SP700 instrument. A blank solution was prepared by carrying out the extraction on a volume of carbon tetrachloride containing the same amounts of starting materials.The calibration graph was produced in a similar way. Determination of 2,6-Dichlorophenol by a Near-infrared Method The mixture containing the phenol and the phenol ether was dissolved in carbon tetra- chloride. Its infrared spectrum was obtained by means of a Unicam SP700 instrument in a l-cm cell between 3 600 and 35OOcm-l. The calibration graph had been prepared previously. Results and Discussion By using the spectroscopic methods it was possible to measure the infrared absorption peak of the phenolic -OH group of 2,6-dichlorophenol [4], which appears at 3 530 cm-1 in solution in carbon tetrachloride and which differs significantly from the -NH- stretching vibration of N-methylpiperazine [l], appearing at 3 675 cm-l (Fig.1). 2,4-Dichlorophenol was similarly determined in industrial waste water sample^,^ at concentrations of 6 x 10-6- 5 x 1 0 - 3 ~ . r-3 43C-NuN-H Cl (j-'- I 3 500 3 600 3 700 Wavenum ber/cm-' Fig. 1. Near-infrared spectrum of compounds [l) and [4]. The other two components of the reaction, [2] and [3], show no absorption in this region, and in the calibration solutions it was possible to monitor whether any of components [1]-[3] influenced the intensity of the phenol peak at 3 530 cm-1. It can be shown (Table I) that the intensity of the phenol peak in solution in carbon tetra- chloride is independent of the concentration of 2,6-dichlorophenyl butyl ether [2] over a wide range; however, it is influenced by the presence of N-methylpiperazine [l].The intensity of the phenolic -OH peak at 3 530 cm-l decreased with increasing concentration of N-methyl- piperazine [l], which can be explained by consideration of the interaction between 2,6-di- chlorophenol [4] and N-methylpiperazine [l]. When the concentration of [l] was kept stable, the intensity of the phenol peak followed the Lambert - Beer law up to 0.2 mg of [4]. This method is of general use for the determination of a phenol if an ether of that phenol is present; nevertheless, it could not be used to solve the kinetic problem of this reaction. TABLE I ABSORPTION VALUES OF PHENOL AT DIFFERENT CONCENTRATIONS OF [I] AND [2] Piperazine* / Phenol Phenol Phenol moll-' absorbance ether t /moll-' absorbance 0 0.256 0 0.923 0.66 x 10-3 0.251 0.5 x 10-3 0.931 1.1 x 10-3 0.238 1.0 x 10-3 0.93 1 2.2 x 10-3 0.226 2.0 x 10-3 0.93 1 4.4 x 10-3 0.179 4.0 x 10-3 0.926 * Concentration of phenol, 1.23 x 10-3 moll-'.f Concentration of phenol, 4.0 x mol I-'.JuZy, 1976 STUDIES ON THE DETERMINATION OF 2,6-DICHLOROPHENOL 521 Of the compounds participating in the reaction only 2,6-dichlorophenyl butyl ether [Z] and 2,6-dichlorophenol [4] showed a strong absorption in the ultraviolet region: for [2], Amax. = 274 nm, log E = 2.78 and Amax. = 281 nm, log E = 2.77; for [4], A,,,. = 280 nm, log E = 3.4 and A,,,. = 287 nm, log E = 3.39. According to the significantly different intensities of aromatic absorption of [2] and [4], a direct, selective assay of [4] in the mixture is theoretically possible.The difference in ultraviolet absorbance between compounds [2] and [a] can be increased significantly if the spectra are measured in 0.1 N sodium hydroxide solution. Under these conditions the spectrum of [Z] remains almost unchanged, while the spectrum of the phenolate ion formed from [4] appears with a strong bathochromic shift and an increased Amax. of 302 nm (log E = 3.71), thus facilitating the selective determination of the latter compound. In this way a rapid, accurate and simple method for following the reaction was derived. Our results (Table 11) proved unequivocally that the reaction rate depends on the molar concentrations of both starting materials [l] and [2] , thus the investigated N-alkylating reaction proceeds via an SN2 mechanism. TABLE I1 RESULTS OF KINETIC INVESTIGATION Values shown are the absorption values of the reaction solution. Ratio of reagent [l] to reagent [2] A I \ Timelmin 1 : 0.5 1 : l 1:2 30 0.064, 0.054 0.088, 0.084 0.107, 0.107 60 0.102, 0.102 0.154, 0.160 0.205, 0.211 120 0.180, 0.182 0.314, 0.328 0.394, 0.408 720 0.460, 0.480 0.840, 0.848 1.140, 1.150 References 1. 2. 3. 4. ti. Reiter, J., SohAr, P., and Toldy, L., Tetrahedron Lett., 1970, 17, 745. Reiter, J., Toldy, L., Acta Chim. Hung., 1974, 82, 99 and 107. Reiter, J., Toldy, L., Acta Chim. Hung., 1975, 87, 69. Tamas, J., Reiter, J., and Toldy, L., Acta Chim. Hung., 1975, 86, 255. Dufek, L., Paper presented at the 7th Analytical Conference in Transdanubium, Sz6kespehdrvAr, Received October 14th, 1974 Amended December 30th, 1975 Accepted January 27th, 1976 1972.

ISSN:0003-2654    

DOI:10.1039/AN9760100519

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

522 A.tzdyst, Jdy, 1976, V O ~ . 101, pp. 522-527 Colorimetric Determination of Aniline in the Presence of 4-Aminophenol and Other Oxidation Products Josef Chrastil Departments of Pharmacology and Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA The extraction of aniline, followed by coupling it with 8-amino- l-naphthol- 3,6-disulphonic acid, and the extraction of 4-aminophenol, followed by allowing its reaction with 1,2-naphthoquinone-4-sulphonic acid, were used for the separation and determination of aniline and 4-aminophenol in admixture. This method facilitates the fast, accurate and specific determination of both components independently. It is suitable for the analysis of biochemical or industrial mixtures containing coloured oxidation products, dyes, plastics, etc.Aniline and 4-aminophenol are commercially important materials, being used in the rubber, dyeing, plastics, petroleum and textile industries. They are very susceptible to oxidation, with the formation of dark coloured products. Thus, it is often necessary to determine aniline in industrial research laboratories in a mixture with these dark coloured oxidation products. Except ior some gravimetric, titrimetric and chromatographic methods, methods which make use of the oxidation of aniline in order to obtain different coloured products are not usable in these instances. Colorimetric methods, such as reaction with 2,4-dinitrophenylamine,l direct coupling of the diazonium salt in a slightly alkaline or strongly acidic medium with N-l-naphthylethylenediamine,2v3 N-ethyl-1-naphthylamine* or 3-hydroxynaphthalene-2,7-di- sulphonic acid,s are not suitable for the determination of aniline in the presence of 4-amino- phenol and other indophenolic oxidation products of aniline. In these laboratories we have studed, for example, the widely used and adapted6-10 method of Bratton and Marshall,2 which involves the use of the coupling reaction with N-l-naphthyl- ethylenediamine in an acidic medium.When used for the determination of aniline this method has several disadvantages : the reaction rate is relatively slow ; the colour (the absorp- tion peak of the purple- violet colour occurs at 530nm) is unstable for about 2 h before it becomes constant ; and the coupling reaction often results in cloudy solutions, requiring the addition of alcohol before reading the colour intensity.Some other reagents have been used for the colorimetric determination of aniline, e.g., 4-dimethylaminobenzaldehyde,ll and for the determination of 4-aminophenol, e.g., silver nitrate in solution in acetone,12 but they are not usually sensitive or specific. The methods described in this paper are suitable for the determination of aniline and/or 4-aminophenol in biological and other material. Both methods have been used successfully for the determination of aniline and 4-aminophenol in metabolic reactions in the liver in v i t ~ 0 . 1 ~ They lack most of the disadvantages of other methods that are described above in that the colour reactions are less widely applicable and the extraction in benzene or ethyl acetate is more specific than extraction in ether, the compounds under determination being stable in these solvents.The methods can also be used for the determination of aniline and/or 4-aminophenol in industrial mixtures containing water-soluble oxidation prodiicts of aniline or 4-aminophenol. Methods Chemical Analysis of Aniline Two millilitres of a solution of aniline, the concentration of which is not in excess of 300 nmol rnl-l, are mixed with 0.5 ml of 0.5 M sodium hydroxide solution, and 1 g of sodium chloride and 20 ml of benzene are added. The mixture is shaken for 10 min and then centri- fuged. A 15-ml portion of the benzene layer is transferred into a conical tube containing 3 ml of 1 M hydrochloric acid. The tube is shaken for 5 min, centrifuged, and 2 ml of theCHRASTIL 523 clear hydrochloric acid layer are transferred to a cold test-tube containing 0.5 ml of 0.2% sodium nitrite solution; the contents of the tube are mixed and kept in a refrigerator (0-5 "C) for 10 min.A 1% solution of ammonium sulphamate (0.5 ml) is next added, mixed with the contents of the tube, and 2 ml of 30% sodium acetate solution are then added and mixed. Finally, 1 ml of a 0.1 yo solution of 8-amino-l-naphthol-3,6-disulphonic acid (sodium salt) (H-acid) is added, the tube contents are again mixed, and the colour is read after 60 min at a wavelength of 530 nm against a reagent blank (without aniline). The last three operations can be carried out quickly at room temperature while the tubes are still cold.A 100 nmol ml-l solution of aniline is used as a standard. Caution-Great care should be exercised in the use of benzene. Chemical Analysis of 4-Aminophenol Two millilitres of a solution of 4-aminophenol, the concentration of which does not exceed 1 pmol ml-l, are mixed with 1 ml of 0.5 M phosphate buffer (pH 7.5) and 1 g of sodium chloride and 20 ml of ethyl acetate are added. The mixture is shaken for 15 min and then centrifuged. A 15-ml portion of the ethyl acetate layer is transferred into a test-tube containing 3 ml of 1 M hydrochloric acid. The tube is shaken for 5 min, centrifuged, and 2 ml of the clear hydrochloric acid layer are transferred to a test-tube containing 1 ml of 10 M sodium hydroxide solution and mixed. A 0.5% solution of 1,2-naphthoquinone-4-~~1- phonic acid (1OOpl) is next added, mixed with the contents of the tube, and the colour read after 5 min at a wavelength of 500 nm against a reagent blank (without 4-aminophenol).A 300 nmol ml-l solution of 4-aminophenol is used as a standard. Analysis of Mixtures of Aniline and 4-Aminophenol Industrial samples, blood, urine or organ homogenates can usually be analysed without previous treatment. However, mixtures containing more than about 300 nmol ml-l of aniline or 1 pmol ml-l of 4-aminophenol must be correspondingly diluted and mixtures containing benzene-soluble coloured products cannot be used. A mixture of the coloured oxidation products of aniline or 4-aminophenol was prepared by heating (for 1 h at 80 "C) 0.01 M solutions of the hydrochlorides of these compounds with a 5% solution of ammonium cerium(1V) sulphate in 0.5 M sulphuric acid (1 + 2).These coloured products were insoluble in benzene and did not significantly affect the determination of aniline. Also, the coloured oxidation products of 4-aminophenol did not significantly affect the method for 4-aminophenol. Results and Discussion The Bratton and Marshall method for determining aromatic compounds with a primary amino group2 lacks specificity. For example, 4-aminophenol reacts and forms a blue colour, and sulphanilamide forms a purple colour. Some biochemically important compounds decrease the colour intensity of aniline significantly (Table I). Another disadvantage of this method is that the colour depends strongly on the pH (Table I ) ; a higher pH before coupling with the Bratton and Marshall reagent results in changes in the spectral characteris- tics of the colour and a decrease in specificity.Thus, the method is sensitive but lacks specificity in the presence of 4-aminophenol, coloured or insoluble products and some bio- chemically important compounds. We have abandoned also the colorimetric method of Brodie and Axelrod6 or Kato and Gillette14 for the determination of 4-aminophenol in admixture with aniline because this ether extraction method is unspecific in the presence of some other compounds (Table 11), which are not completely separated by ether extraction and which deplete the development of the blue colour or react to form another colour. The extraction of 4-aminophenol from solution in phosphate buffer at pH 7.4 into ether and from ether into alkaline phenol solution is not complete.Moreover, aniline and also 4-aminophenol are very unstable in ether and large errors can occur (Fig. 1). We have used 1,2-naphthoquinone-4-sulphonic acid as a reagent for 4-aminophenol. This colour reaction is less sensitive, but more specific, than the reaction with phenol (Table 11). Of the many coupling compounds, the reagent described in Methods (H-acid) had the best characteristics for the reaction with aniline in admixture with 4-aminophenol. For524 CHRASTIL: COLORIMETRIC DETERMINATION OF ANILINE IN THE AnaZyst, VoZ. 101 TABLE I COLOUR REACTION WITH ANILINE AT DIFFERENT pH The standard solutions of aniline and 4-aminophenol were analysed using both methods.The pH of a solution was adjusted by addition of 0.1 M phosphate buffer (1 + 1) plus hydrochloric acid or sodium hydroxide solution just before the coupling reagent was added. In the method described in this paper, sodium acetate (30%) was added before the coupling reagent. By Bratton and Marshall’s method, aniline and also 4-amino- phenol reacted and different colours were formed, with large differences of absorbance a t 530 nm (not shown here). The second method did not give significant differences in colour and absorbance a t 530 nm. PH 0.1 1 2 4 6 8 10 12 I Bratton and Marshall’s method Colour with Colour with A \ / aniline 4-aminophenol Violet Blue Violet Blue Purple Purple Orange Orange Yellow Orange Yellow Red Yellow Red Yellow Red Described method Colour with aniline Purple Purple Purple Purple Purple Purple Purple Purple -%i&zz 4-aminophenol Colourless Colourless Colourless Colourless Colourless Colourless Colourless Colourless TABLE I1 COMPARISON OF THE SPECIFICITY OF THE METHODS FOR THE DETERMINATION OF ANILINE OR 4-AMINOPHENOL The methods suffer interference from compounds listed in this table.However, with the last three methods the influence of these compounds is limited by their solubility in benzene, ether or ethyl acetate. Aniline and 4-aminophenol standard solutions (100 nmol ml-l and 300 nmol ml-l) were determined in the presence of different compounds (300 common compounds, carbohydrates, amino-acids, phenols, amines, heterocyclic compounds and biochemically important substrates were used). The compounds listed interfered in the determinations (by increasing or decreasing the absorbance of standards) when present in the mixture in a concentration of 50% of that of aniline or 4-aminophenol.All other compounds did not influence the determinations in concentrations up to 1 O O O ~ o of the standards. Aniline 4-Aminophenol A L #. \ r * Bratton and Marshall’s method Most phenols Most aromatic amines Most quinones All oxidation products of aniline Most indole derivatives m o l e Retinal Tocopherol Adenine Uric acid Xanthine Riboflavine Guanine Thymine Thiamine 4-Aminophenol Caffeine Pyridine Benzimidazole Benzphetamin e Brucine Kato and Gillette’s Described method method Most aromatic amines Most phenols Benzoxazole Most aromatic amines Benzene soluble oxidation Most quinones products of aniline Glyoxylic acid Ethanolamine Thiamine Phenylpyruvic acid Indene N-Acetylcysteine Thioctic acid G1 yoxal Benzofuran Sugar trioses Antipyrine Benzothiazole Indole derivatives Ether-soluble oxidation products of aniline and 4-aminophenol Described method Most phenols Most quinones Indole derivatives Benzothiazole Antipyrine Benzofuran Ethyl acetate-soluble oxidation products of aniline and 4-aminophenolJU&, 1976 PRESENCE OF 4-AMINOPHENOL AND OTHER OXIDATION PRODUCTS 525 \ \ \ 4 \ \ \ a \ \ B \ \ 4 \ \ \ .. ------ I 200 100 Time/h Fig.1. Stability of 4-aminophenol in peroxide- free ether (B) and in ethyl acetate (A). Astandard solution of 4-aminophen01(300 nmol ml-l) in phos- phate buffer (0.5 M, pH 7.5) was extracted with a ten-fold volume of peroxide-free ether or ethyl acetate.The ether or ethyl acetate layers were separated and analysed after different time intervals a t room temperature; 15-ml aliquots were extracted with 3 ml of 1 M hydrochloric acid and analysed as described under Methods. Dup- licate samples of ether were also analysed by the method of Brodie and Axelrod.6 Similar insta- bility in ether was found with both methods. I0 Time/ m i n Fig. 2. Colour development : determination of aniline. A 200 nmol ml-1 concentration of aniline was analysed as described under Methods. Following the extraction procedure and coupling reaction the colour was read at 530 nm after different time intervals a t room temperature against water as blank. An Acta IV (Beckman) spectrophotometer was used for determinations.example, 2-naphthol-3,6-disulphonic acid (R-acid) , 2-naphthol-6,8-disulphonic acid (G-acid) , 8-aminonaphthalene-2-sulphonic acid (Cleve’s acid), 4-hydroxynaphthalene-2-sulphonic acid (J-acid), etc., did not give colour reactions with aniline under the pH conditions of this method, or they reacted to give colours that were less intense and/or much less specific when in admixture with 4-aminophenol and other interfering compounds. Development of the colour takes 30-50 min (Fig. 2) and the colour is then stable for many hours. The colour intensity is linear up to concentrations of aniline of 300 nmol ml-1. The TABLE I11 RECOVERY OF ANILINE AND 4-AMINOPHENOL FROM BIOLOGICAL MIXTURES AND OXIDATION PRODUCTS Aniline and 4-aminophenol standards in water were mixed (1 + 1) with rat liver homogenates (1:3 in tris buffer, 0.1 M, pH 7.4) or with the neutral solution of oxidation products prepared as described under Methods.The mixtures were analysed by the methods for aniline (A) and 4-aminophenol (B). The recovery was measured as a percentage of the absorbance a t 530 nm (A) and a t 500 nm (B). Recovery from Water Compound or Amount/ mixture pmol ml-1 A, % B, yo Aniline . . .. 0 0 0 Aniline . . .. 0.1 100 1 Aniline + 4-Aminophenol . . 0.3 1 100 4-aminophenol 0.1 + 0.3 100 101 Liver homogenate - A, % B, % 0 0 100 0 1 100 103 102 v Oxidation products - A, yo B, yo 0 0 100 0 2 100 102 99526 CHRASTIL : COLORIMETRIC DETERMINATION OF ANILINE IN THE AutaZyst, VoZ. 101 recovery of aniline from tissue homogenates or from the oxidation products was very good (Table 111).Under the conditions described in Methods, more than 98% of aniline was extracted into benzene and more than 98% of aniline wa,s extracted back from the benzene into hydrochloric acid. The solution of aniline in benzene was stable at room temperature for several days. Blanks were either very low or zero. The method described in this paper for the determination of aniline has relatively good specificity (Table 11) and is not sensitive to changes in pH (Table I). 4-Aminophenol does not react and does not interfere in the reaction because it is insoluble in benzene. Time/min Fig. 3. Colour stability: determination of 4- aminophenol. A 1 pmol ml-l concentration of 4-aminophenol was used for determination of the colour stability of the reaction of 4-amino- phenol with 1,2-naphthoquinone-4-sulphonic acid as described under Methods.Following the ex- traction procedure, the colour was read on an Acta IV (Beckman) spectrophotometer at 500 nm against water as blank. The colour reaction of 1,2-naphthoquinone-4-sulphonic acid with 4-aminophenol also has relatively good specificity (Table 11). Another advantage of the described method is that 4-aminophenol in ethyl acetate is a very stable solution (remaining stable for several days). This would not be true of the solution obtained in the above-mentioned ether extraction method (Fig. l).6J4 The colour intensity increases linearly with concentration up to 1 pmoI ml-1 of 4-aminophenol. At room temperature the colour develops immediately, fading very slowly (Fig.3). Aniline does not interfere in this reaction. More than 95% of TABLE IV DETERMINATION OF ANILINE AND/OR 4-AMINOPHENOL IN MIXTURES The standard solutions of aniline or 4-aminophenol were prepared in water and analysed by different methods. Determination of Determination of aniline 4-aminophenol Kato and Described Described Gillette's method, Bratton and Marshall's method, method, f A > f A > Compound or Amount/ absorbance a t method, absorbance absorbance at absorbance at 620 nm 0.006 mixture pmol ml-l 530 nm at 530 nm 600 nm Aniline 0.01 0.030 0.050 Violet 0.004 Aniline + 4-aminophenol 0.01 + 0.01 0.033 0.076 Blue - violet 0.012 0.025 Aniline 0.1 0.302 0.471 Violet 0.002 0.018 4-Aminophenol 0.1 0.002 0.232 Blue 0.073 0.168 Aniline + 4-aminophenol 0.1 + 0.1 0.312 0.705 Blue - violet 0.07 1 0.181 Aniline 0.3 0.906 1.280 Violet 0.003 0.021 4-Aminophenol 0.3 0.003 0.612 Blue 0.210 0.485 Aniline + 4-aminophenol 0.3 + 0.3 0.926 1.803 Blue - violet 0.225 0.519 4-Aminophenol 0.01 0.001 0.021 Blue 0.010 0.021J d Y , 1976 PRESENCE OF 4-AMINOPHENOL AND OTHER OXIDATION PRODUCTS 527 the 4-aminophenol was extracted into the ethyl acetate and more than 95% was extracted back from the ethyl acetate into hydrochloric acid. Blanks at 500nm were either very low or zero.Both methods, for aniline and for 4-aminophenol, need no special pre-treatment of the samples or tissue homogenates. Usually, after appropriate dilution, samples can be used directly for analysis. The possible nitrosobenzene or 4-nitrosophenol are determined together with the aniline or 4-aminophenol and cannot be distinguished from them.Aniline and 4-aminophenol can be present in the mixture without interfering with each other (Table IV). The enhanced specificity for both materials and the decreased possibility of systematic errors is the basic advantage of this method. This work was supported by grants from the NIH (GM-15431, GM-21949). 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. References McIntire, F. C., Clements, L. M., and Sproull, M., Analyt. Chem., 1953, 25, 1757. Bratton, A. C., and Marshall, E. K., J . BZoZ. Chem., 1939, 128, 537. Montgomery, M., and Freed, V. H., J . Agric. Fd Chem., 1959, 7, 617. Kratochvil, V., 2. AnaZyt. Chem., 1961, 183, 267. Daniel, J. W., Analyst, 1961, 86, 640. Brodie, B. B., and Axelrod, J., J . Pharmac. Exp. Therap., 1948, 94, 22. Kiese, M., Arch. Pharmak. Exp. Path., 1963, 244, 387. Kampffmeyer, H., and Kiese, M., Arch. Pkarmak. Exp. Path., 1964, 246, 397. Lange, G., Arch. Pharmak. Exp. Path., 1967, 257, 230. Clarke, E. G. C., “Isolation and Identification of Drugs,” Pharmaceutical Press, London, 1971. Kupfer, D., and Bruggeman, L. L., AnaZyt. Biochem., 1966, 17, 502. Balasiewicz, W., and Bellen, Z., Chemia Analit., 1969, 14, 267. Chrastil, J., and Wilson, J . T., Biochem. Med., 1975, 13, 89. Kato, R., and Gillette, J. R., J . Pharmac. Exp. Therap., 1965, 150, 279. Received November l l t h , 1975 Accepted February 9th, 1976

ISSN:0003-2654    

DOI:10.1039/AN9760100522

出版商:RSC    

年代:1976

数据来源: RSC

摘要:

528 Analyst, J d y , 1976, Vol. 101, $+. 528-532 Spect,rophotometric Determination of Parathion and Paraoxon Using Alkaline Hydroxylamine Solution for the Liberation of 4-Nitrophenol N. Ramakrishna and B. V. Ramachandran Indian Drug Research Laboratory, Poona-411 005, India The half-time for the liberation of 4-nitrophenol from parathion (diethyl 4-nitrophenyl phosphorothionate) at 20 "C in the presence of 0.5 M sodium hydroxide solution is several hours, but this time can be reduced nearly a 1 000-fold when the alkali is replaced with a mixture of 0.5 M sodium hydroxide solution and 0.67 M hydroxylamine solution. The reaction is almost instan- taneous when the system also contains 33% of ethanol. A procedure is described, based on these findings, for the spectrophotometric determination of parathion and paraoxon via the 4-nitrophenol liberated. The method is simple and quantitative and does not involve the use of drastic chemical procedures such as those required for methods that are currently available. The sensitivity of the method is about 0.1 pmol of parathion.Mixtures of parathion and paraoxon can be determined by using a selective extraction procedure. For the study of the metabolism, both activative and degradative, of parathion (diethyl 4-nitrophenyl phosphorothionate) it was necessary to have a simple and~reasonably accurate method for the extraction and determination of parathion and its toxic oxygen analogue paraoxon (diethyl 4-nitrophenyl phosphate) in aqueous suspensions and enzymic digests. The colorimetric methods available at present for parathion are time consuming and involve the use of drastic chemical procedures.These methods are not suitable when it is necessary to analyse a large number of samples. For example, in the procedure described by Averill and Norrisl reduction of the nitro group to an amino group in the presence of zinc dust and acid is followed by diazotisation and coupling with a chromogenic reagent ; and in the method of Buckley and Colthurst2 parathion is refluxed with alcoholic sodium hydroxide solution and the liberated 4-nitrophenol is determined spectrophotometrically. In a recent paper, Ehagwat and Ramachandran3 reported that in the instance of EPN (ethyl 4-nitrophenyl phenylphosphonothionate) , which is also determined by the procedures mentioned above, the substitution of alkali by a mixture of alkali and hydroxylamine greatly hastened the liberation of 4-nitrophenol and the reaction could be carried out at room tempera- ture.In the present paper the catalytic effect of hydroxylamine on the hydrolysis of the 4-nitrophenol moiety has been applied in the determination of parathion, and a method is described for the colorimetric assay of parathion after its extraction from aqueous sus- pensions with 2-methylpropan-1-01 - benzene (1 + 1). Also, a procedure has been developed for the determination of paraoxon in the presence of parathion, which is based on the easy extractability of the former into alkaline hydroxylamine solution from a solution of both analogues in cyclohexane. Experimental Apparatus Bausch and Lomb, Spectronic 20, s9ectrophotometer.Use with cuvettes of 1-cm light path. Reagents Stock solution of parathion, 100 pmol ml-l. Dissolve 0.728 g of parathion [98% pure, obtained through Bayer (India) Ltd., P.O. Box No. 1436, Bombay-1] in 25ml of acetone and store the solution in a refrigerator. Stock solution of paraoxon, 100 pmo1 ml-l. Dissolve 0.688 g of paraoxon (obtained from Sigma Chemical Co., St. Louis, Mo., USA) in 25 ml of acetone and store the solution in a refrigerator. 4-Nitrophenol solution. Dissolve 0.139 g of 4-nitrophenol (AnalaR grade) in 5 ml of ethanolRAMAKRISHNA AND RAMACHANDRAN 529 and dilute to 100 ml with water. Then dilute 5 ml of this solution to 500 ml with 0.05 M sodium hydroxide solution to give a final concentration of 4-nitrophenol of 0.1 pmol ml-1.Hydroxylammonium chloride solution, 2 M. Dissolve 139 g of the pure substance in water and dilute to 1 1. Filter and store the solution in a refrigerator. Sodium hydroxide solution, approximately 3.5 M. Dissolve 140 g of pure sodium hydroxide pellets in water and dilute to 11. Store the solution in a refrigerator. Sodium hydroxide solution, approximately 0.05 M. Obtain by dilution of the 3.5 M solution. Alkaline hydroxylamine solution. Prepare freshly by mixing equal volumes of 2 M hydroxyl- ammonium chloride solution and 3.5 M sodium hydroxide solution. These solutions are stored in a refrigerator in order to avoid generation of heat on mixing. The mixture is stable for not more than 1 h. Hydrochloric acid, a@roxirnately 0.1 and 0.2 M.2-Methylpropan-1-01 - benzene mixture. Mix equal volumes of the analytical-reagent grade solvents. Caution-Benzene is highly toxic. Pipetting of this solvent should be carried out by means of a dispenser. Re-distilled cyclohexane (boiling range 80-82 "C) . Ethanol, 96-99yo. Triton X-100 solution, log/,. Dissolve 5 g of Triton X-100 in water and dilute to 60 ml. Prepare fresh solutions weekly. Tris - hydrochloric acid bufer solution, 0.05 M in tris, pH 7.6. Dissolve 6.05 g of pure tris(hydroxymethy1)aminomethane in about 250 ml of water distilled in all-glass apparatus. Add 384 ml of 0.1 M hydrochloric acid and dilute to 2 1. Check the pH and make minor adjustments by using a suitable pH meter. Preparation of Calibration Graph for 4-Nitrophenol Pipette 5, 10, 15, 20, 25, 30, 35 and 40 ml of 4-nitrophenol solution into 100-ml calibrated flasks.Add 10 ml of ethanol to each flask and make up to the mark with 0.05 M sodium hydroxide solution. Determine the absorbance of the solutions at 410 nm. Using the average of two determinations of the absorbance at each concentration, plot the calibration graph. Prepare a second calibration graph in the same way but without the addition of ethanol. The standard solutions contained 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 and 0.4 pmol of 4-nitro- phenol in 10 ml, which is the volume used in the methods described below. At these con- centrations the presence of ethanol increases the absorbance of 4-nitrophenol by about 4% and as ethanol is required in the liberation of 4-nitrophenol from parathion and paraoxon by alkaline hydroxylamine solution the appropriate amount has been included in the solutions used in the preparation of the calibration graph.When alcohol is not used in a determination the other calibration graph is used. The amounts of parathion and paraoxon in a sample can be read in micromoles from the calibration graph for 4-nitrophenol. Determination of Free 4-Nitrophenol in a Sample of Parathion Pipette 1 ml of the stock solution of parathion into a stoppered measuring cylinder con- taining 1 ml of 10% Triton X-100 in 0.1 M hydrochloric acid. Adjust the volume to 100 ml with hydrochloric acid and shake the cylinder and contents well in order to obtain a uniform suspension. Extract 10 ml of the suspension with 10 ml of 2-methylpropan-1-01 - benzene by shaking in a separating funnel for 1 min.Add 10 ml of 0.05 M sodium hydroxide solution and shake the funnel for 15s. Withdraw the lower layer and filter through fluted paper. The corresponding value for the concentration, divided by ten, is the amount of free 4-nitrophenol in 1 ml of parathion suspension. Free 4-nitrophenol in paraoxon can be determined in a similar manner. Determination of Parathion Dry the 2-methylpropan-1-01 - benzene layer by shaking with about 1 g of anhydrous sodium sulphate. Pipette three 0.4-ml aliquots of the solution to dry test-tubes (approxi- mately 15 x 1.8 cm) and evaporate to dryness in an air oven at 120 & 5 "C (3045 min). Cool the test-tubes to room temperature and add 1 ml of ethanol followed by 2 ml of alkaline hydroxylamine solution to each test-tube.After a period of not less than 5 min dilute each Discard the lower layer. Determine the absorbance of the filtrate at 410nm.530 RAMAKRISHNA AND RAMACHANDRAN : SPECTROPHOTOMETRIC AnaZyst, VoZ. 101 solution to 10 ml with water. Filter through fluted paper and determine the absorbance of the filtrate at 410 nm. The corresponding value for the concentration, multiplied by 2.5, gives the parathion content of 1 ml of suspension. Determination of Parathion and Paraoxon in Mixtures Make separate suspensions of parathion and paraoxon by dispersing 1 ml of the stock solution in 100 ml of 0.1 M hydrochloric acid containing 0.1% of Triton X-100. Prepare mixtures of the parathion and paraoxon suspensions so that they contain approximately 25, 60 and 75% of paraoxon and are of total volume 40 ml.Pipette 5 ml of suspension mixture and 5 ml of 2-methylpropan-1-01 - benzene into a separating funnel and shake well. Remove any free 4-nitrophenol as described above and dry the 2-methylpropan-1-01 - benzene layer with anhydrous sodium sulphate. Pipette six 0.4-ml aliquots of the solution into test-tubes and evaporate to dryness at 120 "C. To three of the test-tubes add 1 ml of ethanol and 2 ml of alkaline hydroxylamine solution and determine the 4-nitrophenol liberated. The value read from the calibration graph for solutions of 4-nitrophenol that contain ethanol gives a value for parathion plus paraoxon. To the other three test-tubes add 1 ml of cyclohexane and 2 ml of alkaline hydroxylamine solution.Shake the test-tubes manually or mechanically for at least 5 min. Dilute the aqueous layer to 10 ml, separate, filter and determine the absorbance of the filtrate. The value read from the calibration graph for solutions of 4-nitrophenol without ethanol gives a value for para- oxon only. The parathion content of the mixture is determined by difference. The values obtained must be multiplied by 2.5 in order to obtain the parathion and para- oxon contents of 1 ml of the original mixture. The shaking time can be reduced to 3 min if 0.1% Triton X-100 is incorporated in the alkaline hydroxylamine solution. Application of the Method to Technical Parathion Formulations and Enzymic Digests The methods described are intended primarily for the extraction and determination of parathion, paraoxon and 4-nitrophenol in enzymic digests. However, these methods can also be applied to the analysis of technical parathion and formulations.For parathion dusts extract a suitable amount with ethanol or acetone and add the extract to 0.1 M hydrochloric acid containing 0.1% of Triton X-100 in order to form a suspension. Emulsions should also be dispersed in Triton X-100, as the emulsifier in commercial prepara- tions is found to be insufficient to give a uniform suspension. For technical parathion dissolve the sample in ethanol or acetone. Analyse the suspensions as described above. Although a dilute ethanolic solution of parathion can be treated directly with alkaline hydroxylamine solution in order to liberate 4-nitrophenol, the values obtained are invariably high, presumably owing to the dark condensation products in the samples which interfere in the spectrophoto- metric determination. Therefore, it is necessary to disperse the solution in Triton X-100 and hydrochloric acid, and to extract with 2-methylpropan-1-01 - benzene.A typical enzymic digest is prepared and treated in the following way. Prepare a suspension that is 2 x M in parathion by dispersing 1 ml of stock solution in 45 ml of tris - hydro- chloric acid buffer solution containing 0.5 ml of 10% Triton X-100. After equilibration at 37 "C add 5 ml of a 10% mouse-liver homogenate in the same buffer solution. Withdraw 5-ml aliquots at 10-min intervals and add to 5 ml of 0.2 M hydrochloric acid and 10 mi of 2-methylpropan-1-01 - benzene in a separating funnel.Extract by shaking gently for about 1 min and separate as much of the 2-methylpropan-1-01 - benzene layer as possible, with a brief centrifugation if necessary. Dry this layer and determine as described above the amount of free 4-nitrophenol, paraoxon and parathion in aliquots of the solution. Results and Discussion The non-enzymic hydrolysis of parathion by alkali to diethylphosphorothioic acid and hitrophenol is a slow proces~,~ the half-life being several hours, depending upon the strength of the alkali and the temperature. In the official method of assay5 parathion is refluxed for 30 min in 75% ethanol that is 0.5 M in potassium hydroxide. In the present work the half-lives of parathion and paraoxon were determined at 20 "C in various alkaline media and the results are given in Table I.The details of the methods used are the same as those previously given for EPN.3 It can be seen that the reaction rate is about 1 000 times faster if, instead of a purely aqueous system that is 0.5 M in alkali, a medium that is 0.5 M in alkaliJuly, 1976 DETERMINATION OF PARATHION AND PARAOXON TABLE I RATE OF HYDROLYSIS OF PARATHION AND PARAOXON IN VARIOUS MEDIA 53 1 Values calculated from first-order rate constants as in reference 3. average of 2 to 4 determinations. Medium Temperaturel'C 0.05 M Sodium hydroxide solution . . . . 20 0.5 M Sodium hydroxide solution* . . . . 20 33% ethanolict .. . . .. .. 20 0.67 M hydroxylamine, aqueousx . . .. 20 33% ethanolic . . .. .. .. . . 20 0.5 M Sodium hydroxide and 25 30 Results given are the Half -1ifelmin Parathion Paraoxon Too slow 26.6 3821 3.7 616 2.6 74.3 Too rapid 3.7 Too rapid 1.7 - 1 Too rapid - * One volume of parathion or paraoxon suspension in 0.3% Triton X-100 and water added to 2 volumes of a 1 + 1 mixture of 3.6 M sodium hydroxide solution and 2 M hydrochloric acid. t One volume of organophosphate solution in ethanol added to 2 volumes of the alkali - acid mixture.1 One volume of parathion or paraoxon suspension in 0.3% Triton X-100 and water added to 2 volumes of a 1 + 1 mixture of 3.5 M sodium hydroxide solution and 2 M hydroxylam- monium chloride solution. and 0.67 M in hydroxylamine and that contains 33% of ethanol is used. The reaction rate is much faster at 25 "C and almost instantaneous at 30 "C.With paraoxon the reaction rate with alkali is uniformly rapid and the reduction of half-life due to the presence of hydroxylamine is not so marked as for parathion. The actual mech- anism of "hydroxylaminolysis' ' is not clear. The concentration of hydroxylamine used in these studies is 0.67 M, which is the concentration employed in ester analysis in the well known Hestrin procedure* and used by Bhagwat and Ramachandran for the routine deter- mination of malathion.' It is likely that the concentration needed for optimum catalysis may be different. Preliminary experiments indicated that 2-methylpropan-1-01 - benzene, which was intro- duced by Martin and Doty8 for the extraction of molybdophosphoric acid, can extract parathion, paraoxon and 4-nitrophenol from slightly acidic media (pH below 3).The free 4-nitrophenol can be leached out from this solvent with 0.05 M alkali.3 As this solvent does not show volume changes on mixing with water, aliquots can be pipetted out for evaporation and assay. Neither parathion nor paraoxon can be extracted from this solvent by prolonged shaking with alkali or alkaline hydroxylamine solution. No loss of parathion or paraoxon occurred during evaporation at 120 5 5 "C for up to 60 min, which was the maximum period tried. There are no convenient methods for the quantitative determination of parathion and paraoxon in mixtures. The available methods are based on paper or thin-layer chromato- graphygJ0 and are only semi-quantitative. Even as late as 1974, Rhee and Plapp4 used the differential effect of alkali on parathion and paraoxon as the basis for their quantitative determination.Preliminary experiments indicated that whereas parathion can be quanti- tatively recovered from slightly acidic aqueous suspensions by means of a single extraction with an equal volume of cyclohexane, paraoxon was extractable only to the extent of 83-88%. Taking advantage of such differences in solubility, Bhagwat and Ramachandran developed methods for the quantitative determination of the pairs malathion and malaoxonll and EPN and EPNO (the oxygen analogue of EPN).3 The same principle has been applied in the procedure described in this paper for the assay of paraoxon and parathion in mixtures. Table I1 gives the results of shaking parathion and paraoxon solutions in cyclohexane with alkaline hydroxylamine solution for various periods of time.It can be seen that whereas the whole of paraoxon is leached out as 4-nitrophenol in about 5 min, there is no measurable decomposition of parathion even after 30 min. The time required for extraction of paraoxon into alkaline hydroxylamine solution can be further shortened by incorporating 0.1 % of Triton X-100 in the alkaline hydroxylamine solution. A temporary emulsion is formed, thereby facilitating a rapid reaction, which is virtually complete in 2 min.532 RAMAKRISHNA AND RAMACHANDRAN TABLE I1 RATE OF DECOMPOSITION OF SOLUTIONS OF PARATHION AND PARAOXON IN CYCLOHEXANE WHEN SHAKEN WITH ALKALINE HYDROXYLAMINE SOLUTION I n each experiment 1 ml of a cyclohexane solution was shaken with 2 ml of alkaline hydroxylamine solution and the aqueous phase was diluted to 10 ml, filtered and the absorbance of the filtrate determined.Decomposition, % r \ A Time of shakinglmin Parathion* Paraoxon t Paraoxon $ 1 0.0 79.6 97.7 2 - 87.6 99.3 3 - 97.7 100.0 4 - 100.0 100.0 100.0 6 0.0 100.0 10 0.0 100.0 100.0 30 0.0 - - * One millilitre of cyclohexane contained 40 pmol of parathion. Mechanical shaking was used t One millilitre of cyclohexane contained 0.4 pmol of paraoxon. $ One millilitre of cyclohexane contained 0.4 pmol of paraoxon. The alkaline hydroxylamine after 5 min. solution contained 0.1 yo of Triton X-100. Mixtures containing known amounts of parathion and paraoxon were prepared and analysed as described under Experimental. The results are given in Table 111.It can be seen that the recoveries are satisfactory. By introducing cyclohexane into the system and substituting alkaline hydroxylamine solution for alkali, the differential effect of alkali on parathion and paraoxon observed by Rhee and Plapp4 has been considerably accentuated. When parathion and paraoxon were added to mouse-liver homogenates which had previously been heat inactivated, the recoveries were quantitative. These results as well as those for the analysis of active enzyme preparations will be published elsewhere. TABLE I11 ANALYSIS OF MIXTURES OF PARATHION AND PARAOXON Amount recovered f standard deviation* r \ A Amount taken/ pmol Paraoxon Parathion pmol pmol -h 0.40 100 Pa-ion k 0.00 0.40 0.00 - 0.20 0.20 0.198 f 0.007 (9) 99.2 0.202 f 0.011 (9) 100.8 0.30 0.10 0.293 0.019 (12) 97.7 0.106 f 0.027 (12) 106.0 * Number of determinations in parentheses. 0.10 0.30 0.106 f 0.012 (8) 105.0 0.297 f 0.011 (12) 99.0 0.40 0.00 0.392 f 0.006 (14) 98.0 0.00 - The authors thank Dr. G. S. Pendse, Honorary Director of the Indian Drugs Research Association, for his interest in the work, and the Council of Scientific and Industrial Research, New Delhi, for a research grant. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. References Averill, P. R., and Norris, M . V., Analyt. Chem., 1948, 20, 753. Buckley, R., and Colthurst, J. P., Analyst, 1954, 79, 285. Bhagwat, V. M., and Ramachandran, B. V., J . Ass. Off. Analyt. Chew., 1974, 57, 1288. Rhee, K. S., and Plapp, F. W., jun., J . Agric. Fd Chem., 1974, 22, 261. “Official Methods of Analysis of the Association of Official Analytical Chemists,” Eleventh Edition, Association of Official Analytical Chemists, Washington, D.C., 1970, Section 6.286. Hestrin, S., J . Bid. Chem., 1949, 180, 249. Bhagwat, V. M., and Ramachandran, B. V., J . Ass. 08. Analyt. Chem., 1973, 56, 1339. Martin, J. M., and Doty, D. M., Analyt. Chem., 1949, 21, 966. Coffin. D. E., and Savary, G.. J . Ass. 08. Agric. Chem., 1964, 47, 875. Coffin, D. E., and McKinley, W. P., J . Ass. Off. Agric. Chem., 1963, 46, 223. Bhagwat, V. M., and Ramachandran, B. V., J . Ass. Off. Analyt. Chem., 1974, 57, 1043. Received October 14th, 1975 Accepted January 15th, 1976

ISSN:0003-2654    

DOI:10.1039/AN9760100528

出版商:RSC    

年代:1976

数据来源: RSC