ANALYTICAL CHEMISTRY.I. INTRODUCTION.ANALYSIS is " the separation, the identification or the determinationof the concentration of part or all of the constituents or components ofa sample." This dispassionate statement, one of the definitions recentlyrecommended by the Committee on Nomenclature, Division of AnalyticalChemistry of the American Chemical Society,l is one to which no onecould take serious exception. It is bald, but in a definition there is noroom for imagination. An article of faith, as distinct from a definition,has also, however, recently been forthcoming.2 " Analysis, qualitative andquantitative, is the basis of the technique of chemical operations. Nosynthesis can be accounted complete until the synthesised product has beenanalysed, its component parts established and determined.In fact,chemistry is founded, is based, on analysis. The theories of the thinkers areproved or disproved by analysis ; the guesses of the inspired can only becomecertainties through the manipulation of the analyst." Up to this point thedefinitive essence parallels precisely enough with the previous quotation , andthe addenda are the logical consequences of serious thinking about the placeand scope of this branch of chemistry.It would not, however, be right to end the quotation a t this point, sincethe sequel contains more than the germ of a truth. It continues: " Butanalysis is not a separate discipline, although from the importance it hasattained . . . it might be assumed it were an end in itself.Although analysisis but an aspect of chemical technique, the analyst himself has almostbecome such a specialist that he may be divorced from the genuine trend ofchemical development and become immersed in the study of the break-downof compounds or of the determination of ' pointers ' to the composition ofnatural or of manufactured compounds. And so it is that one of the dan-gers. . . is that workers lose their love of chemistry, and, instead, take tothemselves analysis. 'This divorce from the genuine trend of chemical development, a veryreal danger in any branch of chemistry, is perhaps particularly so in analyticalchemistry, and is always to be seen in any close survey of the literature.Specific aspects of it will appear later in this Report.On the general issue,however, it behoves anyone presenting advances in analytical chemistry toconsider how best his work can serve the general body of chemistry. Thesubject may range over the vast field from the most specialised of appliedanalyses to fundamental problems whose spheres of influence are obviouslylarge though their boundaries may not be clearly discernible. The ad hocwork of the industrial analyst may be of no interest to the vast mass ofanalytical chemists, much less to the body of chemists in general. On theother hand it might well have within it an idea which, more widely knownL. T. Hallett e t aZ., AnaZyt. Cham., 1952, 24, 1348.L. H. Lampitt, Analyst, 1952, 77, 564WILSON : INTRODUCTION. 299and applied, could revolutionise some branch of chemistry.One must, then,take note of those apparently minor papers which “ analytical intuition ”or one’s own interest suggests might be of interest to one’s chemical colleagues.One must do this, moreover, always unpleasantly aware of the unreliabilityof intuition’s aid. Who would have been inspired by a paper describingphysicochemical studies on chlorophyll in 1906 or one on the manipulationof small precipitates in 1909 4 to forecast that these were seeds which wouldproduce, in 1923 and in 1952, Nobel prizes awarded for distinction in thefield of analytical chemistry ?At the same time the Reporter must select from the extensive series ofpapers dealing specifically with analytical chemistry-certainly more than4000 per annum-those which will present a starting point for any analystwishing to follow up any particular section. His selection must in additionrepresent fairly the distribution of work throughout the past year.In thisway chemists whose main interests are other than analytical may be able tonote activities and to judge trends.His selection, however, must always be personal, and it can never behighly critical. It is possible to refute or to support a theory. But analyticalchemistry is in excelsis that branch of the science where the proof lies at thebench. A method may sound promising, or novel, but until one has triedit one can rarely say more than this about it.There is still that“ trend of chemicd development ” and the action and reaction between it andthe field of analytical chemistry.Just as the chemist benefits from thework of the analyst in all fields, the analyst must benefit from the work ofthe chemist in all fields. The necessity for fundamental research in analyticalchemistry was stressed in this Report last year. The fundamental work may,however, be of two kinds-that done by analytical chemists within their ownfield, usually easy to recognise; and that done by other workers, who haveno knowledge that they are increasing (and perhaps, indeed, no desire toincrease) the resources of the analyst. Assessment of such work mustagain, of necessity, be largely by intuition and personal interest, but nowadditionally hampered by the fact that one is working outside one’s specialistfield.Themost obvious fundamental development in which the analytical chemistmust interest himself at the present time is that dealing with the structuresof organometallic compounds.Both within and without the analyticalfield this branch has been increasingly active during the past few years anda valuable survey of this field is now a~ailable.~“ In the long term the majorpart of the work must fit together to form a pattern. At the present time,since little assembly and less pattern can be said to exist, it can only be hopedthat a few of the more critical pieces near the centre can be indicated.None of these major aims of the Reporter will be satisfactorily achieved ;but the Report may, in spite of this, attain a final form which will please someof the people some of the time.With all this the Reporter’s work is not finished.Indeed, the selection on this last basis must almost be random.M.Tswett, B e y . deut. bot. Ges., 1906, 24, 316.F. Emich and J. Donau, Monatsh., 1909, 30, 746.A. E. Martell and M. Calvin, “ Chemistry of the Metal Chelate Compounds,” NewYork, 1952300 ANALYTICAL CHEMISTRY.In Great Britain, in 1952, much interest was centred in the InternationalCongress held in Oxford in September, and now fully documented,5 and inthe smaller, but still quite important Symposium in Birmingham whichfollowed the Congress, and which is, as yet, only reported in abstract form.sFrom the former of these we have freely and gratefully used one of theCongress lectures to illustrate our opening remarks.Individual papers willbe reported in their appropriate places.The remaining two Congress lectures may be mentioned here as expressingclearly two topical aspects of analytical chemistry. R. H. Muller,’ indealing with research in analytical instrumentation, was mainly concernedwith future trends. He maintained that analytical chemists have not yetmade anything like full use of the resources of the science of instrumentation,although he claimed that the use of instruments is widespread and alreadydominates many types of analysis.” The use of the term “ dominates ” is,one would hope, ill-founded, and is, perhaps, a slip, since the speaker wenton to point out that the analyst could, and more and more should, relegatehis instrumental problems to the specialist, but that only the analyst coulddetermine the problems.The other Congress speaker, C.J. van Nieuwenburg8 was concernedwith the place of “ classical ” methods in analytical chemistry. The growthof instrumental methods has given rise in some quarters to the belief thatclassical methods are a dying species. This he regards a9 completely un-founded. That the two opposite types of solution to analytical problems arenot opposed types, but are capable of being employed together, was hisprincipal theme. The variety of weapons available has been increasedrather than altered. His conclusions are strikingly similar to those ofMiiller when one considers the different terms of reference. He holds thatinstrumentation and organisation “ will not be any use unless there areleading men who understand the whole job.Maybe the old classical methodswill disappear some day, although I do not think that day is very near. Butthe old classical knowledge of analytical chemistry will remain. In thelong run brains will count.”The practice of analytical chemistry has been discussed on other occasions.It is significant that similar conclusions regarding the need for integrationof instrumental and classical methods, rather than a complete replacementof classical by instrumental methods, is explicitly emphasised from thepedagogic point of view 9 as well as implicitly from that of the professionalpractitioner.10 In the latter case we are reminded that the practisinganalytical chemist is called upon to apply “ a knowledge not only of hisbackground in the field of analytical chemistry, but the broadest backgroundof chemical subjects that he can command, and to strive for a solution bythe application of known methods, principles and procedures in flew patterns.”Much of the research in analytical chemistry today is concerned, not with theprovision of new principles and methods, but with the summation of know-ledge in a new way..Analyst, 1952, 77, 557 ff.Ind.Chem. Chem. Manuf., 1952, 28, 487.Analyst, 1952, 77, 557.Ibid., p. 573.9 P. W. West, J . Chem. Educ., 1952, 29, 222.l o S. E. Q. Ashley, Analyt. Chem., 1952, 24, 1690WILSON GENERAL. 3012. GENERAL.In the Progress Report of the Committee on Nomenclature alreadyreferred to,1 specific definitions are put forward as recommendations, but theReport is not regarded as final.A number of the definitions are not novel,but it is useful to have them in compact form. The term ‘‘ volumetric,”it is recommended, should refer to measurement by volume, and is not to beregarded as synonymous with “ titrimetric,” which is measurement bytitration. This is a view that will be welcomed by many analysts, althoughit will require constant caution to prevent falling into the older usage.Definitions are proposed, based on sample size, for the prefixes macro-,semimicro-, micro-, and ultramicro-, and this is more likely to be a subjectfor future debate.It is somewhat unexpected, in view of the distinction that some workershave stressed in the past between “ iodimetry ” and “ iodometry,” to findthat “iodometry” is defined as the measurement of concentration bytitration with a standard solution of iodine ; but measurement of concentra-tion by titration with a standard solution of thiosulphate is denoted by theterm “ thiosulphatimetry.” There seems to be no reason for the divergenttreatment of the two terms, and one wonders on what basis the Committeewill discriminate between the various forms that have been proposedfrom time to time for the performance of titrations by measurement ofconductance.The definitions so far proposed are limited in number, and many termshave yet to be considered.A more detailed Report on proposed terms and definitions in appliedspectroscopy has also been published.ll In the Report, in addition toproposals, a group of general principles of nomenclature-standardisation isstated, and there is also included a list of terms about which no decision hasyet been reached.The preparation of sodium chloride suitable for use as a primary analyficalstandard has been described.12 Acetylsalicylic acid l3 and sulphamic acid 14have been proposed as primary standards in alkalimetry.The former hasthe advantage that its purity can be checked, after titration, by hydrolysiswith excess alkali to salicylic acid, and back titration, which should indicatethe consumption of a further equivalent of alkali. The latter reagent isknown to hydrolyse slowly, a slight but appreciable test for sulphate beingobtained after six days storage of the solution.The hydrolysis is to bi-sulphate, however, and the replaceable hydrogen of the sulphamic acidought merely to be substituted by the replaceable hydrogen of the bi-sulphate. In consequence there should be no alteration in the normalitytowards alkali; no appreciabIe change in normality was found, on test, after213 days. The advantages claimed for the reagent are its ready solubilityin water; the fact that it is an acid only slightly weaker than the mineralacids so that it can be titrated readily by using indicators whose workingrange is pH 4 - 9 ; and the ease of obtaining and maintaining it in a highl1 H. K. Hughes et al., Analyt. Ckenz., 1952, 84, 1349.l2 L. Meites, J . Chem. Educ., 1952, 29, 74.lS F.Barriel, F. Pino, and M. D. Vinuesa, Afinidad, 1950, 87. 337.l4 W. F. Wagner, W. F. Wuelher, and C. E. Feiler, Amlyt. Chem., 1952, 24, 1491302 ANALYTICAL CHEMISTRY.state of purity. In addition, since practically all its salts are soluble, thereis little danger of interference with the titration through formation ofprecipitates.Calcium acid malate hexahydrate has been recommended l5 as a standardfor alkalimetry and for the calibration of pH meters. In addition it provesuseful as a standard for calcium titrations-a field which has extendedconsiderably in recent years (p. 305). With a very high equivalent weight of207, it possesses all other desirable qualifications of such a standard exceptthat it cannot be dried a t 100".However, it is non-hygroscopic, and anytrace of adsorbed moisture, which is not a likely feature, can be removed byaspiration of dry air over the solid. The same solid may be used indirectlyas a standard for acidimetry by ignition to the oxide, solution of this in excessof acid, and back titration with alkali.Statistical aspects of analytical chemistry have been discussed by anumber of authors.16 Methods for approximating to the standard deviationhave been proposed and applied to practical examples.1' The reconciliationof scientific and statistical hypotheses, in the special case of radiochemistry,has been considered.18H. Ballczo l9 has pointed out some of the ways in which errors in titri-metric analysis, particularly with dilute solutions, may be reduced byattention to calibration of apparatus and to temperature corrections.Thespecial case of the double titration has been included in this treatment. Thepossible sources of error inherent in weighing techniques have been discussedby M. J. Marteret.20 The titrimetric error arising from adsorption of silverions on glass has been studied by a radioactive indicator method.21The importance of training students of chemistry to appreciate sourcesof error has been pointed out,22 and a suitable course outlined which includessuch procedures as the determination of uncertainty in analytical results.It has also been stressed 23 that in addition to operational error there may,in such conditions, also be instructional error, which may exist even ifstudents obtain the correct result.The consequences of this, methods ofappreciating its existence, and methods of reducing it have been outlined.Tables have been issued for use in the calibration of graduated glass-ware24 and specifications have been drawn up for one-mark graduatedflasks 25 and automatic microchemical burettes.26The field of inorganic microchemistry has been reviewed,27 and semi-micro-techniques for titrimetric analysis, employing sealed vessels of thepharmaceutical-serum type, and hypodermic syringes, with measurementscarried out by weighing rather than by volume, have been described.28Its only notable drawback is its low molecular weight.l6 A. C. Shead, Analyt. Chem., 1952, 24, 1451.l6 R. J. Hader and W. J.Youden, ibid., p. 120; W. J. Youden, Analyst, 1952, 77,874; G. E. P. Box, ibid., p. 879; E. G. Gracheva, J . Anal. Chem., U.S.S.R., 1952, 7 , 48;J. M. Pertierra, Inform. Qudm. analit., 1952, 6, 117.17 B. Woolf, Nature, 1952,170, 631 ; H. de Miranda, Chenz. Weekblad, 1951, 47, 1046.18 L. Martin, Analyst, 1952, 77, 892.lo 2. anal. Chem., 1952, 134, 321.z1 H. M. Hershenson and L. B. Rogers, Analyt. Chem., 1952, 24, 219.2z W. R. Carmody, J . Chem. Educ., 1952, 29, 349.a* W. J. Blaedel, J. H. Jefferson, and H. T. Knight, ibid., p. 480. *' B.S.I. Specif., 1952, No. 1797.26 Ibid., No. 1428, Pt. D1.31 D. M. Smith, J. Mitchell, and A. M. Billmeyer, ibid., p. 1847.2o Chim. analyt., 1952, 34, 149.Ibid., No. 1792.P. W. West, Analyt. Chem., 1952, 24, 76WILSON : GENERAL.303A general review of ultramicro-quantitative analytical methods has beengiven,29 and micro-manipulators 3c, 31 and other apparatus 31s 32 designed forwork on the microgram scale have been described.Reagents.-In the field of reagents there has been much work of directuse to the analytical chemist, and probably even more that is likely to beof future importance to him. A. E. Martell 33 has discussed some of the waysin which aqueous metal ions are affected by complex formation, with par-ticular reference to the formation of chelate compounds. Such propertiesas solubility, electrical conductance, interaction with hydrogen ions, ab-sorption spectra, oxidation potentials and, above all, stabilities as measuredby the equilibrium constants of the formation reactions, are all fundamentalproperties which are of value in the investigation of the formation of com-plexes.Such study must lead to the development of new and valuableapplications of complex fonnation. New analytical reagents utilisingunusual oxidation states have been reviewed.34Many investigations of the structures of complexes have been reported,both by analytical chemists and by those outside the field of analyticalchemistry, and it is difficult to determine which of these will, in the longterm, have most significance. In this connection earlier comments regardingthe tendency of the analytical chemist to fall behind the general stream ofdevelopment have considerable force. It is unfortunate that in many of thestudies which have been made on organometallic compounds, and, indeed inthe general literature of analytical chemistry, there is a tendency to clingto conceptions which are, as far as the general theory of chemistry is con-cerned, out-of-date and by now almost meaningless.Thus the classificationof such complexes which was current some time ago, and which was neveranything more than an ad hoc classification, into groups such as “ pene-tration,” and “ inner-complex ” compounds, still persists in many of thepublications, although modern ideas on the structures and binding forces ofmolecules, atoms, and ions permit us at least to discard this for somethingmore in keeping with the times. Ina t least one recent publication valencies were referred to as “ principal ”and “ auxiliary,” which might almost be said to smack of the phlogistonera.If analytical chemists are to make satisfactory contributions to thetheoretical side of this topic, they must familiarise themselves with modemideas on bond structure, and they can, with profit, read some of the public-ations referred to in this section. Many of these, which have no direct orimmediate bearing on practical problems of analytical chemistry, seem tocontribute significantly to the theory of complex-formation, and thus to havean ultimate value for the man a t the bench.It is, perhaps, going to the other extreme to refer, as some authors do, tocompounds such as calcium oxalate and calcium acetate under the classific-ation of complexes.While it is true that an extreme current view is to regardany anion derived from more than one atom as a complex ion, the term‘ I complex ” loses much of its significance, in the analytical sense a t least,and probably also in a wider field, if some sort of division is not indicatedSuch terms still appear too frequently.a9 A. E. Sobel and A. Hanok, Mikrochem. Mikrochim. Acta, 1952, 39, 51.ao T. Brindleand C. L. Wilson, ibid., p. 310.33 A. Lazarow, J . Lab. Clin. Med., 1951, 38, 660.34 M. Kapel, Ind. Chem. Chem. Manuf., 1952, 28, 466.31 M. C. AlvarezQuerol,ibid., p. 117.33 J . Chem. Educ., 1952, 20, 27304 ANALYTICAL CHEMISTRY.between these structures and the more complicated ones which are normallyclassed as complexes. It may be that the distinction will be supplied by theincreasing use of the term " chelates."There is now available an excellent account 4a of methods of study inthis field, and of the results which these methods have so far given.Anorder of stability for metal complexes has been reported, and generallyspeaking, this seems to agree among the various groups of complexes be-tween the metallic ions and a variety of organic compounds.35 The studiesalso support the greater stability of five- than of six-membered chelates.It is found that zinc, nickel, and cobalt(I1) co-ordinate with three moleculesof tropolone to form singly charged ions, while the corresponding copper(n),beryllium, and lead complexes contain only two organic molecules and areneutral.The co-ordination chemistry of the transition metals has been studied,36and magnetic data for many of these compounds have been related tovalency, structure, and bond type, with particular reference to the ionic orcovalent nature of the linking.From a more strictly analytical point ofview H. M. Irving and R. J. P. Williams 37 have considered a number of thefactors controlling the action of organic reagents. The stabilities of thecomplexes have been considered in relation to their solubilities, the nature ofthe metallic ion, the nature and the acid dissociation constant of the reagent,and the pH a t which the complex exists. Particular attention is paid to thespecificity of reagents.H. Freiser 38 discusses stability in relation to analytical use for a widerange of metal-chelate compounds, and brings home clearly the enormousextent of the field which has to be examined before any comprehensivetheory can be advanced, and the complexity of the factors involved, suchas steric hindrance and solubility.In this paper particular examples usedfor illustrative purposes are 2-o-hydroxyphenylbenzoxazole as a reagent forcadmium, 2-o-hydroxyphenylbenzothiazole for copper or cadmium, and2-0-hydroxyphenylbenziminazole for mercuric mercury.Probably the reagent which has received most analytical attentionthroughout the past year is ethylenediaminetetra-acetic acid. Uses for thisreagent were reviewed in last year's Report,39 but many extensions ofexisting uses and many new uses have since been developed.The uses of thisreagent and of the related nitrilotriacetic acid have been reviewed from apractical point of view 40 and theoretical aspects of its application have beendiscussed.41claims that in order to overcome the instability of theindicator Eriochrome Black T [or sodium 1-( 1-hydroxy-2-naphthy1azo)-5-nitr0-2-naphthol-4-sulphonic acid] it may be made up in diethanolamine ortriethanolamine solution, which will remain stable for at least seven months.It should be stored in such a way that the solution is protected from atmo-E. M. Diskanta6 B. E. Bryant, W. C. Fernelius, and B. E. Douglas, Nature, 1952, 170, 247.36 F. H. Burstall and R. S. "yholm, J., 1952, 2906, 3570; R. S. Nyholm and A. G.Sharpe, ibid., p. 3579. 37 Analyst, 1952, 77, 813.38 Ibid., p.830. 39 Ann. Reports, 1951, 48, 311.40 M. 0. Lawson, IRd. Chem. Chem. Manwf.., 1952, 28, 512, 559; G. C. Krijn, Chem.Weekblad, 1952, 48, 165; H. Flaschka, Mikvochem. Mikvochh. Acta, 1952, 30, 38.4l G. Schwarzenbach, Analyt. Claim. Ada, 1952, '7, 141.42 AnaZyt. Chem., 1952, 24, 1856WILSON GENERAL. 305spheric moisture, but need not be protected from light or from alterations ofatmospheric temperature. Several variants of methods for determination ofcalcium- and total-hardness of water have been proposed,43 and in one casecopper and iron are first removed by addition of cyanide and passage throughan anion-exchange resin column.& The reagent has been widely applied tothe determination of calcium 45 and magnesium 46 in biological fluids, and ofthese elements in other materials such as lirne~tones.~~ The effect of varyingthe concentration of potassium chloride in the calcium determination hasbeen examined.4s Direct or indirect titration methods for a number of otherelements have been proposed.Phosphate is determined by precipitation asmagnesium ammonium phosphate and subsequent determination of themagnesium.49 Barium and zinc 51 may be titrated directly. Sodium maybe estimated through zinc after precipitation as sodium zinc uranyl acetate.62Nickel, first precipitated by dimethylglyoxime, may be titrated directly.53When a solution of a silver salt is allowed to react with ammoniacal nickelcyanide solution, an equivalent amount of nickel ion is set free which may betitrated, thus giving a measure of the silver.54.55 This, in turn, may be usedt o determine halide after precipitation as silver halide. This determinationmay be used in coloured or cloudy solutions where the classical methods forhalide are unsatisfactory. Thallium may be titrated directly with a solutionof the magnesium complex.56 Lead may be titrated directly, either alone 57or in the presence of which latter may be masked by cyanide andthen subsequently estimated by a total titration in absence of cyanide.Apart from its uses as a titrimetric reagent, ethylenediaminetetra-aceticacid has been used to prevent interference in the estimation of ~ u l p h a t e , ~ ~nitrate,60 beryllium,61s 62 and ir0n.6~ It has been recommended for the43 J.E. Houlihan, Analyst, 1952, 77, 158; R. Sijderius, Chern. Weekblad, 1952, 48,44 J. W. McCoy, Analyt. Chim. Acta, 1952, 6, 259.46 A. C. Mason, Analyst, 1952, 77, 529; H. Lempfrid and J. Stiirmer, Klin. Woch-enschr., 1952, 30, 227; H. Neilsen, Nord. Med., 1952, 48, 1059; H. Flaschka and A.Holasek, 2. Physiol. Chem., 1951, 288, 244.IS A. Holasek and H. Flaschka, ibid., 1952, 290, 57; E. S. Buckley, J. C. Gibson, andT. R. Bortolotti, J . Lab. Clin. Med., 1951, 38, 751; A. H. Holtz, Chern. Weekblad, 1951,47, 907; A. E. Sobel and A. Hanok, Proc. SOC. Exp. Biol., N.Y., 1951, 77, 737; KuangLu Cheng and R. H. Bray, Soil Sci., 1951, 72, 449.4 7 J. J. Banewicz and C. T. Kenner, Analyt. Chem., 1952, 24, 1186; Kuang Lu Cheng,T. Kurtz, and R. H. Bray, ibid., p.1640; J . Banks, Analyst, 1952, 77, 484; L. E. Smith,Pulp and Paper, 1952, 26, No. 5, 86, 88; K: E. Langford, Electroplating, 1952, 5, No. 2,41.4 8 F. F. Carini and A. E. Martell, J . Amer. Chem. Soc., 1952, 74, 5744.O9 H. Flaschka and A. Holasek, Mikrochem. Mikrochirn. A d a , 1952, 39, 101; F.Huditz, H. Flaschka, and I. Petzold, 2. anal. Chem., 1952, 135, 333.51 E. W. Debney, Nature, 1952, 169, 1104.5* H. Flaschka, Mikrochem. Mikrochim. Acta, 1952, 39, 391.53 W. F. Harris and T. R. Sweet, Analyt. Chenz., 1952, 24, 1062.64 H. Flaschka, Mikrochem. Mikrochim. A d a , 1952, 40, 21.5 5 H. Flaschka and F. Huditz, 2. anal. Chem., 1952, 137, 104.66 H. Flaschka, Mikrochem. Mikrochirn. Acta, 1952, 40, 42.5 8 H. Flaschka and F. Huditz, 2. anal.Chew., 1952, 137, 172.5D D. Gibbons, I n d . Chem. Chem. Manuf., 1952, 28, 487.8o F. L. Hahn, Analyt. Chim. Acta, 1952, 7, 68.81 J . Hur6, M. Kremer, and F. le Berquier, ibid., p. 37; R. G. Smith, A. J . Boyle,P. I. Brewer, Analyst, 1952,J. A. Adam, E. Booth, and J . D. H. Strickland, Analyt. Chim. A d a , 1952, 6, 462.378; W. Fivian and M. Moser, Sugar I n d . Abstr., 1951, 13, 131.T. J . Manns, M. U. Reschovsky, and A. J. Certa, Analyt. Chem., 1952, 24, 908.5 7 Idem, ibid., 39, 315.W. G. Fredrick, and B. Zak, Analyt. Chem., 1952, 24, 406;77, i 3 9 .63 R. L. Morris, Analyyt. Chem., 1952, 24, 1374306 ANALYTICAL CHEMISTRY.colorimetric determination of cobalt .64 The complexes with europium 65and with thorium and uranyl ions 66 have been examined. R.C. Vickery 6 7 9 68has investigated the stability constants of metallic ions with this reagent,with particular reference to their use in ion-exchange methods for separatingthe lanthanons. He has shown that the elution series for complexes ofbivalent metals is affected by the presence or absence of tervalent metalcomplexes. He has also achieved a good separation of praseodymium fromneodymium by addition of manganese to act as a separating element. Forthe most efficient separation, low concentration of the reagent together witha low flow rate, a high pH value, and an exchange resin in the ammoniumform are recommended. Finally, H. Flaschka 69 has investigated the effectof the presence of ethylenediaminetetra-acetic acid on the behaviour ofthioacetamide as an alternative precipitant to hydrogen sulphide, and hasdescribed the behaviour of a wide range of cations in acid, neutral, andalkaline solution towards the combined reagents.While discussing this reagent it is perhaps pertinent to introduce amore general note.In the literature the range of synonyms for ethylene-diaminetetra-acetic acid is bewildering-EDTA, ED, enta, Complexone(together with its derivative Complexometric titration), Versene, Versenate,and Trilon B all have considerable currency. For an internal report suchnames may have their advantage, but it is doubtful if the space saved in aprinted paper is sufficient to offset the confusion which must exist. Nodoubt the tendency to apply shortened names to organic reagents becamepopular with " oxine," though this has little advantage over 8-hydroxy-quirioline or 8-quinolinol, either of which is unequivocal.It was not alto-gether to be expected by those who incautiously lent " oxine " currencythat we should ultimately be assailed by ferroin, cuproin, neo-cuproin,tiron, magneson-I, and magneson-11, to choose only a few of those whichspring immediately to mind. None of these names gives any clue to thenature of the reagent, and they are not altogether to be trusted as a guide touse. It is true that the nomenclature of organic reagents must cause dismayto those analytical chemists who make use of these reagents, and an easysolution of the problem is not to be expected. But strenuous efforts arebeing made to standardise the nomenclature in other branches of chemistry,and theconclusion has regretfully been reached that many of the trivial namesof the nineteenth century must be retained though they are misleading inthe light of systematic nomenclature.It seems a pity, therefore, that thefield of analytical chemistry bids fair to provide a further problem for com-mittees on nomenclature by the lavish use of trivial names which may ormay not have gained general acceptance.In a comprehensive study of the complexes of copper with 1 : 10-phenan-throline and its methyl derivatives 70 the range of pH which permits of theirformation, and their stabilities have been examined. The structures havebeen related to such properties as absorption spectra, and use has been madeof this in predictions for some of the methyl derivatives.Similar studies** M. Jean, Analyt. Chim. Acla, 1952, 6, 278.8 6 M. J. Cabell, Analyst, 1952, 77, 859.70 W. H. McCurdy and G. F. Smith, AnaZysf, 1062, 77, 346.E. I . Onstott, J . Amer. Chem. Soc., 1952, 74, 3773.Nature, 1952, 170, 665.2. anal. Chem., 1952, 187, 107.6 8 J . , 1952, 4357WILSON : GENERAL. 307have been made for the 1 : 10-phenanthroline complexes with iron(^^),^^iron(111),~~ and zinc.73 Investigations on various oximes and dioximes havebeen rep0rted.7~ Measurements of the stabilities of complexes of 8-hydroxy-quinoline and related compounds 75 confirm the greater stability of 5-membered chelate rings mentioned above, and also indicate an order ofstability for the bivalent metals Cu > Ni > Co > Zn > Pb > Cd > Mn >Mg which is in general agreement with other investigations.It has beenshown that 8-hydroxyquinaldine may be quantitatively brominated, 76 anda number of quantitative precipitations with this reagent, notably of indium,uranyl, scandium, lead, and thorium, have been described.On the assumption that an indophenol of 8-hydroxyquinoline shouldpossess both the redox-indicating properties of indophenols and a pre-cipitating power related to the parent compound, a number of indophenolsof this compound and its derivatives have been prepared.77 Most of theseproducts were unstable. However, 2-methylindo-8-hydroxyquinoline, pre-pared by the action of hydroxylamine in an alkaline oxidising medium on8-hydroxy-Z-rnethylquinoline, gives precipitates a t pH 5 with certain cations,and at pH 12 with a wider range of ions.Work on the stabilities of metal chelates of iminodiacetic acid andiminodipropionic acid and their derivatives 78 suggests an order corre-sponding to that quoted above, but with lead and cobalt interchanged, andagain supports the greater stability of 5-membered chelates.The analyticalbehaviour as precipitants of thiourea and of 4- and 5-phenyl-substituted1 : 2-dimercapto-3-thiones 80 has been reported. Ammonium thiocarb-amate has been recommended 81 as an alternative to hydrogen sulphide forthe precipitation of sulphides. An extensive investigation of disubstituteddithiocarbamates s2 has shown that many metallic ions may be precipitatedas stable crystalline compounds which frequently have characteristic colours,generally brighter than those of the corresponding sulphides.The extract-ability of these metal dithiocarbamates has been investigated.The separation from bivalent cations of iron, aluminium, and man-ganese as hydroxides may be carried out 83 by aminomercuric chloride,NH2=HgCl, prepared in situ through successive additions of mercuric chloride,ammonium chloride, and ammonia. Consideration of the " weighting "effect as applied to benzidine, its homologues, and related compoundsindicate that 4 : 4'-diaminotolane is likely to form a sulphate of lowsolubility.84 This compound has been examined, and found to have theAluminium is not precipitated.'1 W.W. Brandt and D. K. Gullstrom, J. Amev. Chem. SOC., 1952, 74, 3532.72 A. E. Harvey and D. L. Manning, ibid., p. 4744.73 J . M. Kruse and W. W. Brandt, Analyt. Chem., 1952, 24, 1306.74 C. V. Banks and A. B. Carlson, Analyt. Chim. A d a , 1952, 7 , 291; R. Pallaud,7 6 W. D. Johnston and H. Freiser, J. Amer. Chem. SOC., 1952, 74, 5239.7 @ J . P. PhilIips, J . F. Emery, and H. P. Price, AnaZyyf. Chem., 1952, 24, 1033.7 7 J . P. Phillips, J . F. Emery, and Q. Fernando, J. Amer. Chem. SOC., 1952, 74, 5542.78 S. Chaberek and A. E. Martell, ibid., p. 5052; S . Chaberek, R. C. Courtney, and7a K. B. Yatsimirsky and A. A. Astasheva, J. Anal. Chem., U.S.S.R., 1952, 7 , 43.8a H. Malissa and F. F. Miller, Mikrochem. Mikrochim. Acla, 1952.40, 63.83 S. K. Susic and N. V. Njegovan, Analyt. Chim. Acla, 1952, 7 , 304.84 M. Kapel, Ind. Chem. Chem. Manuf., 1952, 28, 490.Chim. analyt., 1951, 33, 239, 343.A. E. Martell, ibid., p. 5057.M. G. Voronkov and F. P. Tsiper, ibid., 1951, 6, 331.E. Wiberg and R. Bauer, Angew. Chem., 1952, 64, 27D308 ANALYTICAL CHEMISTRY.lowest solubility recorded for an amine sulphate. The stabilities of a rangeof alkaline-earth compounds have been discussed theoretically.85General methods for the estimation of magnesium in calcium metal 86and of zinc in zinc-cadmium mixtures 87 have been critically examined.D. C. Atkins and C. S. Garner 88 have divided chelate compounds of zincinto two classes, I‘ fused-ring ” compounds where isotopic exchange withradioactive zinc takes place very slowly if at all, and “ non-fused-ring ”complexes where this exchange is very rapid.The structures and propertiesof salicylideneamine 89 and N-alkylethylenediamine complexes of copperand nickel have been described. An order of stability for amino-acidcomplexes of copper has been related to the structures of the amino-acid~.~lSilver has been shown to form several types of complex ion with triethylene-tetramine,92 The complexes formed by chromium and gallium with iodinehave been studied,93 and the bearing of these on other halide complexes andon general bond-type theory is indicated.In a general article B. J. Lerner, C. S. Grove and R. S. Casey 94 point outthat much of the knowledge required for a complete explanation of the“ complex ” chemistry of iron-knowledge of all forces operating at molecularlevel and a valid all-inclusive theory of valency-is still not available. Suchfactors as solvation, magnetic susceptibility, electron transfer, the effect ofpH, and the relation of colour to structure are discussed. Complexes ofcobalt with salicylaldehyde, its derivatives and related compounds 95 andwith the unusual sexadentate sulphur-containing aw-diamines 96 have beendescribed.Organometallic compounds of cobalt,97 nickel,97* 98 chromium,99uranium,lW and zirconium Io1 have been investigated. Formulae have beenproposed for a number of the ions formed by zirconium in mineral acidsolutions.1O2 The reactions of some thiosemicarbazides with ruthenium havebeen examined. lo33.INORGANIC QUALITATIVE ANALYSIS.In a scheme for the separation and recognition of the more familiarcations, J. Galmes lo* recommends removal of the alkaline-earth metalstogether with the usual chloride group by following the addition of hydro-chloric acid with ethanol and sodium sulphate. After removal of the acid-insoluble sulphides, the cations normally precipitated as hydroxides and as86 R. J . P. Williams, J . , 1952, 3770.8 6 S. Abbey, Chem. Canad., 1951, 3, No. 10. 53.87 W. Scheller and W. D. Treadwell, Helv. Chirn. Acta, 1952, 35, 754.8 8 J . Amer. Chem. SOC., 1952, 74, 3527.8Q A. P. Terentev and E. G. Rukhadze, J . Anal. Chem., U.S.S.R., 1951, 6, 303;91 N. C . Li and E. Doody, ibid., p. 4184.O2 H. B. Jonassen and P.C. Yates, ibid., p. 3388.93 A. S. Wilson and H. Taube, ibid., p. 3509.n4 J . Chem. Educ., 1952, 29, 438. O6 B. West, J . , 1952, 3115, 3123.s6 F. P. Dwyer, N. S . Gill, E. C . Gyarfas, and F. Lions, J . Amer. Chem. Soc., 1952,97 C. F. Callis, N. C . Neilsen, and J. C. Bailar, ibid., p. 3461.O 8 L. Sacconi, ibid., p. 4503. OD W. K. King and C . S. Garner, ibid., p. 5534.loo J. T. Barr and C. A. Horton, ibid., p. 4430.lol H. B. Jonassen and W. R. de Monsabert, ibid., p. 5298.lo2 B. A. J . Lister and L. A. McDonald, J . , 1952, 4315.lo3 R. P. Yaffe and A. F. Voigt, J . Amer. Chem. SOC., 1952, 74, 5043.lo4 Afinidad, 1951, 28, 154.A. P. Terentev, E. G. Rukhadze, and 2. A. Fadeeva, ibid., 1952, 7, 120.F. Basolo and R. K. Murmann, J .Amer. Chern. Soc., 1952, 74, 5243.74, 4188WILSON : INORGANIC QUALITATIVE ANALYSIS. 309sulphides in alkaline solution are precipitated by solid sodium carbonate.The unsatisfactory separation of the alkali-insoluble sulphides from thehydroxides may be overcome, it is claimed,105 by the application of selectivespot tests without reliance on separation methods. An alternative scheme Io6removes the chlorides in the usual manner, followed by tin and antimony,which are separated by evaporation with nitric acid. The insoluble sul-phates and the insoluble hydroxides constitute the two major succeedinggroups. Potassium xanthate is recommended lo' as a satisfactory alternativeto hydrogen sulphide, being used to precipitate a large group of elements,including a number of the less familiar ones, after removal of the insolublechlorides and sulphates.The xanthate group is then subdivided by treat-ment with alkali hydroxide, which produces a group of soluble and a groupof insoluble sulphides.A method has been described lo8 for the preparation of the titaniumreagent recommended for the removal of phosphate in the orthodox schematicMethod of analysis. Alternative procedures have been proposed for thetreatment of the sulphides of the copper group log and the nickel group,l1°and of the alkali-metal group.111J. Gillis 112 has discussed a number of aspects of theoretical and practicalimportance regarding the " sensitivity " of a reaction. The general fieldof spot reactions has been reviewedJ113 particularly with reference tospecificity.Among tests for the identification of individual ions a method has beenoutlined for the removal of interferences before detecting chloride by silvernitrate.ll* A bismuth mercaptoglyoxaline gives a red complex with iodidewhich is specific for this Nitrate may be removed and identified asvolatile methyl nitrite.l16 Sulphur in any form is reduced to hydrogensulphide which gives a red colour with a molybdate-thiocyanate s01ution.l~~Thiocyanate is extracted and identified by a ferric chloride-aluminiumchloride reagent .l18 Azo-dyes based on pyrocatechol and haematoxylinare sensitive colour reagents for boric a~id.11~ A range of specific reagentsfor germanium has been critically examined, and their behaviours de-scribed.120 R.J. Winterton 121 has investigated claims for sodium cobalti-thiosulphate, sodium calcium ferrocyanide, and sodium uranyl chromate asl06 A. Okac and M. Bezdek, Publ. Fac. Sci. Univ. Masaryk, 1950, No. 3, 9.lo6 F. Bianchi, Monit. Farm. Terap., 1952, 58, 139.lo' L. R. Chaves Lavin, Inform. Quint. anal., 1951, 5 , 62.lo8 A. J. Nutten and W. I. Stephen, Analyt. Chim. Acta, 1952, 7, 31.log M. S. Jovanovic and B. M. Jovanovic, Bull. SOC. chim. Belgrade, 1951, 16, 167.110 E. G. Maleeva, J . Anal. Chem., U.S.S.R., 1951, 6, 383.111 A. Casini, Ann. Chim. Roma, 1952, 42, 317.112 Mikrochenz. Mikrochim. Acta, 1951, 38, 381 ; J , Chem. Educ., 1952, e9, 170; Ind.113 F. Feigl, Mikrochem. Mikvochim. Acfa, 1952, 39, 368; P. W. West, Analyst,114 C.Mahr and W. Bromer, 2. anal. Chew.., 1952, 135, 107.116 R. A. McAllister, Nature, 1952, 169, 708.116 C. Franzke and K. Romminger, 2. anal. Chem., 1952, 136, 1.117 L. P. Pepkowitz and E. L. Shirley, Nuclear Sci. Absfv.. 1952 6. 15.L. Mennucci, Rev. Fac. Cienc. quim., La Plata, 1947, 22, 7.119 I. M. Korenman and F. R. Sheyanova, J . Anal. Chem., U.S.S.R., 1952, 7, 128.lao P. Bevillard, Mikrochem. Mikvochim. Acta, 1952, 89, 209;Chem. Chem. Manuf., 1952, 28, 488.1952, 77, 611.A. Tchakirian andP. Bevillard, Compt. vend., 1951, 233, 256, 1033.Ind. Chem. Chem. Manzcf., 1952, 28, 482310 ANALYTICAL CHEMISTRY.precipitants for potassium. None of these has proved as sensitive as sodiumcobaltinitrite, although the first may be used to detect rubidium in theabsence of potassium, and the first and last may prove useful as tests forpotassium in the presence of ammonium, as no precipitate is given by thelatter ion.A spot procedure for the detection of zinc using potassium ferrocyanide,122and methods for the recognition of cadmium after precipitation as an am-monium iodide complex 123 and of mercury as red cuprous mercuric iodide 124have been described.Alizarin-blue, which contains the active groups ofboth alizarin and 8-hydroxyquinoline, may be used for the detection of tracesof copper,125 although the general behaviour of the individual reagents haslargely been lost by combining the two structures. Aluminium, bismuth,iron, and titanium are precipitated by diphenyl phosphate.126 Manganesegives a green colour with triethanolamine in the presence of alkali hydr-0xide,1~~ and is satisfactorily detected in field tests on minerals by 8-hydroxy-quinoline.128 The zinc 1 : 10-phenanthroline complex mentioned earlier 73may be used to provide a sensitive test for ferricyanide in the presence offerrocyanide.F. Buscarbns and J. Artigas 129 recommend 2-mercapto-acetamido-4-nitrophenol as a reagent for cobalt. Gossypol forms a redcomplex with rn01ybdenum.l~~ It is claimed I 3 l that the interference offluorides in the detection of molybdenum by orthodox reagents is not somarked as has previously been reported, and that detection is still possiblein the presence of 100 times its concentration of fluoride as sodium fluoride.A photochemical reaction of tungsten in the presence of hydrochloric acidand ethanol is stated 132 to be suitable for the detection of a few pg.of thiselement. Tungsten may also be detected in ores by 8-hydroxyquin01ine.l~~The test for antimony with rhodamine-B may be made specific for thiselement, and will enable 0-2 pg. to be detected.134On the assumption that the mandelic acid group, *CH(OH)*CO,H, shouldbe generally sensitive for zirconium, R. E. Oesper, R. A. Dunleavy, andJ. J. Klingenberg 135 prepared m-2-hydroxynaphthylazomandelic acid so asto introduce a coloured centre into the reagent. As expected, this forms acoloured precipitate with zirconium, but the precipitate has the same colouras the reagent. It may be used, however, semi-quantitatively by theconfined spot-test technique.Colour reactions between finely divided solids have been discussed 136as a basis for qualitative analysis, and a number of highly sensitive testshave been described which may be applied directly to minerals.122 A.Lewandowski, Roczn. Chem., 1952, 26, 8.12s A. A. Komarovskaya, J. Gen. Chem., U.S.S.R., 1949, 19, 1459.124 E. Van Dalen and B. Van't Riet, Analyt. Chtm. Acta, 1952, 6, 101.1 2 ~ F. Feigl, Ind. Chem. Chem. Manu.., 1952, 28, 487.126 F. Knotz, Anal. veal SOC. esp. Fis. Quim., 1952, 48, B, 564.12' E. Jaffe, Ann. Chim. Roma, 1951, 41, 397.A. de Sousa, Analyt. Chim. Acta, 1952, 7, 393.120 Anal. real SOL. esp. Fis. Quim., 1952, 48, B, 140.A. Vioque-Pizarro, Analyt. Chim. Acta, 1952, 6. 105.lS1 F.Bermejo Martinez, A. Prieto Bouza, and J . Flores de Ligondes, Anal. real SOC.lS2 A. de Sousa, Analyt. Chzm. Acta, 1952, 7 , 24.lSs Idem, Mikrochem. Mikrochim. Acta, 1952, 40, 104.lS4 P. W. West and W. C. Hamilton, Analyt. Chem., 1952, 24, 1025.lS6 Ibid., p. 1492.esp. Fis. Quim., 1951, 47, B, 523.136 P. M. Isalrov, J. Anal. Chem., U.S.S.R., 1951, 6, 281WILSON : INORGANIC GRAVIMETRIC ANALYSIS. 31 14. INORGANIC GRAVIMETRIC ANALYSISFive types of weighing vessel have been specified for microchemicalana1y~is.l~~ W. H. Rromund and A. A. Benedetti-Pichler 138 have de-scribed the use of an assay balance for the gravimetric analysis of milligramsamples with use of microchemical equipment. A quartz microbalance forthe determination of magnetic susceptibility on milligram samples has beendescribed 139 and its performance investigated.The ageing of crystalline precipitates has been considered from thetheoretical standpoint by I.M. Kolthoff,lm and factors influencing bothphysical and chemical ageing have been discussed. It has been suggestedthat some form of numerical indications of the analytical characteristics of aprecipitate such as “ coefficient of filtration,” “ rate of sedimentation,” lQ1and “ nucleation potential ” 142 should be available. Such values would be avaluable guide to the analytical behaviour of precipitates. They might permita more fundamental approach to precipitation problems, and they wouldhelp in the development of new or the improvement of existing methods.Precipitation in Homogeneous Solution.-The method by which theprecipitating agent is produced slowly throughout the body of the solution,so that uniform precipitating conditions are achieved, continues to beextended.Calcium maybe determined in the presence of magnesium by using the hydolysis ofmethyl oxalate.lU Barium has been precipitated by the hydrolysis ofsulphamic a ~ i d . 1 ~ ~ Praseodymium has been separated from lanthanum bythe fractional precipitation of the carbonates from trichloroacetic acidsolution. 146 Thorium is gradually precipitated by ammonium picrate orby 2 : 4-dinitrophen01,l~~ and lead is satisfactorily precipitated as phosphatein a solution whose pH is altered gradually by the hydrolysis of urea.148Recent gravimetric methods of analysis have beenre~iewed.14~ C.Duval 150 has collated earlier work, using the thermobalance.From a study of the thermolysis curves, nitron, cinchonamine, and di-l-methylnaphthylamine are recommended 151 as gravimetric reagents fornitrate; no reagent tested was found to be suitable for the determination ofnitrite, hyponitrite, or azide. R. C. Brasted 152 has described an indirectgravimetric determination of nitrite through the loss in weight from gasevolution with sulphamic acid. Optimum conditions have been proposed 153for the determination of phosphorus as ammonium phosphomolybdate,A review of existing methods has been made.143Methods OJ analysis.n7 B.S.I. Specif., 1952, No. 1428, Pt. H1.lS8 Mikvochem. Mikrochim. Acta, 1951, 38, 505.18s F.Blaha, ibid., 1952, 39, 339.A. V. Nikolaev and M. P. Elentukh, J . Anal. Chem., U.S.S.R., 1952, 7, 21.142 R. A. Johnson, I n d . Chem. Chem. Manuf., 1952, 28, 489.I43 L. Gordon, Analyf. Chem., 1952, 24, 459.L. Gordon and A. F. Wroczynski, ibid., p. 896.145 W. F. Wagner and J . A. Wuellner, ibid., p. 1031.146 L. L. Quill and M. L. Salutsky, ibid., p. 1453.14’ C. L. Rao, M. Venkataramaniah, and B. S. V. R. Rao, J . Indian Chem. Sot., 1951,140 F. E. Beamish and W. A. E. McBryde, Analyt. Chem., 1952, 24, 95.I 5 O Chim. anal., 1952, 34, 55.151 C. Duval and N. D. Xuong, Analyt. Chim. Acta, 1952, 6, 245.lS2 Analyt. Chem., 1952, 24, 1111.lS3 -4. Bacon and H. C. Davis, Metal Abstr., 1952, 19, 734.140 Analysf, 1952, 77, 1000.28, 515.Shu-Chuan Liang and Kuo-I Lu, Analyt. Chim. Acta, 1952, 7, 451312 ANALYTICAL CHEMISTRY.either in simple phosphate solutions or in the presence of iron or chromium,and for the determination of sulphate as barium sulphate in the presence ofir0n.1~~ Following a study of five co-ordination compounds of cobalt,octa-ammino-pamino-pnitrodicobaltic nitrite has been proposed lS5 asa gravimetric reagent for sulphate. Although the precipitate is moresoluble than barium sulphate, it is little affected by foreign ion adsorption.In particular, nitrate does not interfere. Germanium may be estimated by3 : 4-dihydroxya~obenzene.~~~Critical examination of the precipitation of potassium with sodiumcobaltinitrite lS7 has confirmed the unsuitability of this reagent for thegravimetric determination of potassium, even under the most stringentempirical conditions, because of variability in the structure of the pre-cipitate and co-precipitation of reagent. If this reagent is used, some indirectmethod of determination, such as that based on a colorimetric cobalt deter-mination, must be utilised.The gravimetric determination of potassium aspotassium tetraphenylboron, K[B(C,H,),],lS8 is claimed to be rapid and freefrom error. A method has been described for the separation of rubidiumand caesium in large amounts of sodium and potassium chl0rides.15~ Theprecipitation of beryllium and its deterrnination as pyrophosphate havebeen critically examined, and suitable procedures have been selected. 160J.L. Walter and H. Freiser 161 have found 2-o-hydroxyphenylbenzox-azole, one of the reagents which they investigated from the structural pointof view,38 suitable as a gravimetric reagent for cadmium. Only nickel andcobalt interfere seriously, and copper interference can be avoided. Micro-gram amounts of mercury in the mercurous form have been determinedgravimetrically as the chloride with a coefficient of variation of _+l%.lSZInvestigations with the thermobalance have indicated some twenty gravi-metric methods which are suitable for the determination of copper, with the.conditions which are appropriate for drying the pre~ipitates.1~~ Copper maybe determined gravimetrically as cuprous thiocyanate by using ferrousammonium sulphate as reducing agent,164 or as sulphide by using theammonium or sodium salt of trithiocarbonic acid as precipitant.165 Pre-cipitation of copper with 6 : 6-benzoquinaldinic acid has been described.166Silver has been determined gravimetrically on the microgram scale as thechloride,162 and gold may be precipitated by morpholine 0xalate.1~'Aluminium can be precipitated quantitatively as the hydroxide byusing pyridine.16* Interference by iron in the precipitation with ammonium154 N.Gandolfo, R. C . 1st. sup. Sanit., 1951, 14, 654.156 R. Belcher and D. Gibbons, J . , 1952, 4216.156 A. Tchakirian and P. BCvillard, Compt. rend., 1951, 233, 1112.157 D. Bourdon, Chim. anal., 1950, 38, 273; J. W. Robinson, I ~ d . Chem. Chem.158 H. Flaschka, 2. anal. Chem., 1952, 136, 99; H.W. Spier, Biochem. Z . , 1952, 322,160 R. Airoldi, A n n . Chim. appl, Roma, 1951, 41, 478.161 Nuclear Sci. Abstr., 1952, 6, 212; Analyt. Chem., 1952, 24, 984.1's Y. Marin and C. Duval, Analyt. Chim. Acta, 1952, 6, 47.16* R. Belcher and T. S. West, ibid., p. 337.165 E. Gagliardi and W. Pilz, Monatsh., 1952, 83, 54.166 A. K. Majumdar and A. K. Mallick, J . Indian Chem. SOC., 1952, 29, 255.1e7 L. S. Malowan, Rev. SOC. venezol. Quim., 1961, 5, No. 23, 23.1 6 8 E. Peltenburg, Rev. Fac. Cienc. qrim., La Plata, 1947, 23, 175.Manzif., 1952, 28, 491.467. 159 D. Meier and W. D. Treadwell, Helv. Chim. Acta, 1951, 34, 805.H. M. El-Badry and C . L. Wilson, Analyst, 1952, 77, 596WILSON INORGANIC GRAVIMETRIC ANALYSIS. 313hydroxide may be prevented by complexing with thioglycollic acid.169The micro-determination of aluminium with 8-hydroxyquinoline has beenm0dified.1~~ Lanthanons may be precipitated by ammonium sebacate.171From themolytic examination, tetraphenylarsonium perrhenate isstated to be the most satisfactory weighing form for rhenium.17a Iron andchromium may be precipitated as the hydroxides with pyridineJ168 andcobalt as the double mercuric thiocyanate.173 Molybdenum may be separ-ated from interfering elements by a preliminary precipitation with u-benzoin oxime followed by conversion into ~u1phide.l~~ The sulphide mayalso be obtained by precipitation with sodium trithi0~arbonate.l~~ Amethod for volatilisation of tin as stannic iodide permits estimation of thiselement in br0nzes.1~~ Lead has been determined with phenylarsonicacid 177 and on the microgram scale as sulphate.162For the quantitative precipitation of zirconium, benzilic acid,178 cinnamicacid,179 and salicylic and phenoxyacetic acids 180 have all been found satis-factory.Quantitative precipitants proposed for thorium include cam-phoric,181 anisic,l82 ~uccinic,18~ adipic,l83 b e n ~ o i c , l ~ ~ ~ 184 and m-tolyloxy-acetic acids,lS5 ammonium furoate,lg6 sodium suIphani1ate,ls6 and cinnamicacid.Antimony may be precipitated as the sulphide by sodium trithio-carbonate 188 or as a cobalt complex with bisethylenediaminocobalticchloride. ls9 Vanadium may be precipitated with diantipyrylphenyl-methane and ignited to the pentoxide. The temperatures of decompositionof a number of niobium complexes have been rec0rded.1~~ Separation of thetannin complexes of niobium and tantalum may be achieved in aqueousammonium oxalate s01ution.l~~ From temperatures of decomposition,precipitation of tantalum by tartaric acid is indicated as the most satisfactoryof the current methods.lg3lG9 R.A. Hummel and E. B. Sandell, Analyt. Chim. Acta, 1952, 7, 308.170 M. C. Alvarez Querol, Mikrochem. Mikrochim. Acta, 1952, 39, 121.171 G. B. Wengert, R. C. Walker, M. F. Loucks, and V. A. Stenger, Analyt. Chem.,172 S. Tribalat and C. Duval, Analyt. Chim. Acta, 1952, 6, 138.173 F. Sierra and F. Ckrceles, Anal. real SOC. esp. Fis. Quim., 1951, 47, B, 811.174 J , Iron Steel Inst., 1952, 171, 75.175 E. Gagliardi and W. Pilz, 2.anal. Chenz., 1952, 136, 103.1 7 G J. Besson and R. Budenz, Chinz. anal., 1952, 34, 163.177 A. K. Majumdar and R. N. S. Sarma, J . Indian Chem. Soc., 1951, 28, 654.17* M. Venkataramaniah and B. S. V. R. Rao, ibid., p. 257.179 C. Venkateswarlu and B. S. V. R. Rao, ibid., p. 354.180 T. V. Sastry and B. S. V. R. Rao. ibid., p. 530.lS1 D. 9. N. Murty and B. S. V. R. Rao, ibid., p. 218.lS2 K. V. S. Krishnamurty and B. S. V. R. Rao, ibid., p. 261 ; Rec. Trav. chim.,T. V. S. Suryanarayana and B. S. V. R. Rao, J . Indian Chem. Soc., 1951, 28, 511.lS4 M. Venkataramaniah, C. L. Rao, and B. S. V. R. Rao, AnaEyst, 1952, 7'4, 103;lS6 M. Venkataramaniah, B. S. V. R. Rao, and C. L. Rao, Analyt. Chem., 1952,24,747.lS6 0. Lakshminarayana and B. S. V.R. Rao, J . Indian. Chem. SOC., 1951, 28, 551.lS7 K. V. S. Krishnamurty and C. Venkateswarlu, Rec. Trav. chim., 1952, 71, 668.lSs E. Gagliardi and W. Pilz, 2. anal. Chenz., 1952, 136, 344.l90 S . I. Gusev, li. G. Beyles, and E. V. Sokolova, J . Anal. Chem., U.S.S.R., 1951,lB2 N. H. Bailey, S. A f r . I n d . Chem., 1951, 5, 235.lg3 U. M. Doan and C. Duval, Analjlt. Clzim. Acta, 1955, 6, 135.1952, 24, 1636.1951, 70, 421.J . Sci. Ind. Res., India., 1951, 10, B, 254.D. Gibbons, I n d . Chem. Chem. Manuf., 1952, 28, 487.6, 43. lgl U. M. Doan and C. Duval, Analyt. Chinz. Acta, 1952, 6, 81314 ANALYTICAL CHEMISTRY.Precipitation of platinum by thioformamide is stated lg4 to be moresatisfactory than precipitation by hydrogen sulphide, and reduction ofprecipitated ammonium hexachloroplatinate by zinc is recommended inpreference to the more usual meth0ds.1~5 Errors in the assay of iridium lg6and of osmium lg79 lg8 have been investigated, and precipitation of osmiumby " thionalide '' followed by ignition in hydrogen to the metal is recom-mended.Palladium may be precipitated as the sulphide by thioform-amide lg9 or as a complex with 1 : 10-phenanthroline.2C@ The latter pre-cipitate or the precipitate with 8-hydroxyquinoline is recommended asweighing form on the basis of thermolysis curves.2o15. INORGANIC TITRIMETRIC ANALYSIS.Recent advances in titrimetric analysis are presented in the new editionof a standard work 202 and in a review.203 A titration bench with built-inlighting and stirring apparatus has been de~cribed.~04 Reductors andreductor methods have been reviewed205 and new or improved reductormethods have been proposed.206 A study by potentiometric methods ofsome of the reactions of bromide-bromate and iodide-iodate systems hasbeen reported.207 An extensive correspondence on the standardisation ofiodine solutions by sodium thiosulphate has stressed the inadvisability ofalkaline stabilisers for standard thiosulphate solutions, and the necessity foracid conditions in the titration.208 A comprehensive review of the titri-metric uses of cerium(1v) solutions has been made.209 L.S. Theobald andJ. P. Stern 210 have recommended methods for preparing standard solutionsof aluminium and zinc.210 The stability of aqueous potassium ferratesolutions to light, temperature, and varying conditions of alkalinity andconcentration has been examined.211 Chloramine-T has been recommendedas a more economical titrimetric reagent than iodine.212 The use of stan-dard stannous ~ h l o r i d e , ~ l ~ potassium rnetaperi~date,~~~ and manganese(II1) 215lg4 E.Gagliardi and R. Pietsch. Monatsh., 1951; 82, 656.lB6 A. P. Blackmore, M. A. Marks, R. R. Barefoot, and F. E. Beamish, Analyt.lg6 R. R. Barefoot and F. E. Beamish, ibid., p. 840.197 W. J. Allan and F. E. Beamish, ibid., p. 1608.lg8 Idem, ibid., p. 1567. lS9 E. Gagliardi and R. Pietsch, Monatsh., 1951, 82, 432.zoo D. E. Ryan, Analyst, 1952, 77, 46.201 P. Champ, P. Fauconnier, and C. Duval, Analyt. Chim. Acta, 1952, 6, 250.202 I ' Neuere massanalytische Methoden," Ed.W. Bottger, 3rd edtn., Stuttgart, 1951.203 C. S. Rodden and C. G. Goldbeck, Analyt. Chem., 1952, 24, 102.*04 W. Schoniger, Mikrochem. Mikrochirn. Acta, 1951, 38, 456.205 W. I. Stephen, Ind. Chem. Chem. Manuf., 1952, 28. 13, 55, 107.208 C. W. Sill and H. E. Peterson, U.S. Bur. Man., 1952, Rep. Invest. 4882; Analyt.Chem., 1952, 24, 1175; J. M. Thompson, ibid., 1632; E. R. Riegel and R. D. Schwartz,ibid.. p. 1803; J . A. Rahm, ibid., p. 1832; C. C. Miller and R. A. Chalmers, Analyst, 1952,77, 2 ; P. Wehber and H. Hahn, 2. anal. Chern., 1952, 136, 321, 325; M. I. Kriventsov,J . Anal. Chem., U.S.S.R., 1951, 6,384; E. GagliardiandW.Pilz, Monatsh., 1951, 82, 1012.207 H. T. S. Britton, R. E. Cockaday, and J.K. Foreman, J., 1952, 3877; H. T. S.Rritton and H. G. Britton, ibid., pp. 3879, 3887, 3892.208 R. Rands, Chem. and Ind., 1952, 1001 ; J. J. Lamond, ibid., p. 1128; A. I. Vogel,ibid., p. 1177; T . A. H. Peacocke, ibid., p. 1245.209 P. Yonng, Analyt. Chem., 1952, 24, 152.210 Analyst, 1952, 7'4, 99.211 W. F. Wagner, J. R. Gump, and E. N. Hart, Analyt. Chem., 1952, 24, 1497.212 W. Poethke and F. Wolf, 2. anorg. Chem., 1952, 268, 244.213 2. G. Szab6 and E. SugAr, Analyt. Chim. Acta., 1952, 6, 293.214 B. Singh and A. Singh, J . Indian Chem. SOC., 1952, 29, 34.215 R . Belcher and T. S. West, Analvt. Chim. Acta, 1952, 6, 322.Chem., 1952, 24, 1815WILSON INORGANIC TITRIMETRIC ANALYSIS. 315solutions as general titrimetric reagents has been described.R. H. Mullerand A. M. Voge1216 have recommended an instrument with temperature-compensation for the standardisation of titrimetric solutions by conductancemeasurements.Methods of Analysis.-From a critical examination of methods for theestimation of hypochlorite, A. Lassieur and D. Jouslin 217 recommendtitration with standard arsenious oxide solution using an internal indicator.Bromide ion may be oxidised to bromate by chlorine 218 or by hypochlorite 219before iodometric determination. Iodide may be accurately titrated bypermanganate,220 and fluoride by zirconium solution.221 Ammonia may beprecipitated by Nessler's reagent, and the precipitate reduced to mercury,which is then treated with iodate-iodide and the liberated iodine estimatedby thiosulphate.222 Treatment of hydroxylamine with excess of cerium(1v)solution enables the compound to be determined by back titration withstandard arsenic solution.223 The estimation of nitrate by the method of2.G. Szabo and L. Bartha 224 has been modified and converted to the micro-scale.225 Azide may be determined by reduction to give an ammonia-nitrogen mixture in which the ammonia is estimated.226and it is statedthat significant errors occur except when the end-point acidity is maintainedwithin the range 1.2-3.5~. Ozone may be determined iodometrically,228and peroxide by titration with ~ e r m a n g a n a t e . ~ ~ ~ Sulphite is oxidised tosulphate by hypochlorite, the excess of hypochlorite being estimated by aniodide-thiosulphate t i t r a t i ~ n .~ ~ ~ G. Denk 231 has shown that a directalkalimetric titration for alkaline-earth metals is possible, and that this mayin turn be applied to the indirect determination of sulphate. Titrimetricmethods have been described for selenium 2329 233 and 234A method for alkali carbonate and bicarbonate in the presence of each otherutilises titration with standard barium chloride and back titration, afteraddition of excess of acid, with carbonate-free sodium Cyanidemay be titrated with standard nickel solution, murexide being used asindicator.236The estimation of potassium as the tetraphenylboron compound 15* may216 AnaZyt. Chem., 1952, 24, 1590.217 A. Lassieur and D. Jouslin, Chim. anal., 1951, 33, 45.21s 2. G. Szab6 and L. Csanyi, Analyt.Chim. Acta, 1952, 6, 208.218 M. R. Block, S. Kertes, and I. Schnerts, Bull. Res. Council Israel, 1952, 1, No. 4, 82.220 S. A. Celsi and M. ,4. Copello, Monit. Farm., 1951, 57, 158.221 H. v. Zeppelin and J. Fuchs, Angew. Chem., 1952, 64, 223.222 H. Lestra and G. Roux, Compt. rend., 1951, 233, 1453.223 S. R. Cooper and J. B. Morris, Analyt. Chem., 1952, 24, 1360.224 Ann. Reports, 1951, 48, 323.225 2. G. Szabo and L. Bartha, Mikrochem. Mikrochim. A d a , 1951, 38, 413.226 L. P. Pepkowitz, Analyt. Chenz., 1952, 24, 900.227 D. J. Kew, M. D. Amos, and M. C. Greaves, Analyst, 1952, 77, 488.228 C. M. Birdsall, A. C . Jenkins, and E. Spadinger, Analyt. Chem., 1952, 24, 662.22e J. Mattner, 2. anal. Chem., 1952, 135, 415.230 B. L. Dunicz and T.Rosenquist, Analyt. Chem., 1952, 24, 404.231 2. anal. Chem., 1952, 137, 99.232 G. S. Deshmukh and B. R. Sant, AnaZyst, 1952, 77, 272.233 K. Geiersberger and A. Durst, 2. anal. Chem., 1952, 135, 11; K. Geiersberger,234 R. A. Johnson and D. R. Fredrickson, Analyt. Chem., 1952, 24, 866.235 D. Koszegi and E. Salgo, 2. anal. Chem., 1952, 137, 22.236 F. Huditz and H. Flaschka, ibid., 136, 185.The bromate titration of arsenic(II1) has beenibid., pp. 15, 18316 ANALYTICAL CHEMISTRY.be completed titrimetrically instead of gravimetricany, an argentometrictitration in acetone solution being Interference from iron,aluminium, and chromium is masked by fluoride. The direct alkalimetricestimation of alkaline-earth metals 231 is possible in hot solution, with sodiumcarbonate, thymol-blue being used as indicator.Beryllium solutions maybe titrated directly with barium hydroxide to a phenolphthalein end-point,or may be estimated by precipitating the hydroxide, treating this withpotassium fluoride, and titrating the liberated alkali with standard acid.238Cadmium and zinc may be indirectly estimated with alkali, making use ofthe fact that the hydroxides or basic carbonates, when dissolved in sodiumthiosulphate, liberate an equivalent amount of acid.2ag The salts of cadmiumwith strong acids may be titrated directly against sodium hydroxide to acresolphthalein end-poin t .mThe effect of nitric acid on the iodometric determination of copper maybe eliminated almost completely by addition of sufficient solid sulphamicacid to retain crystals in the solution throughout the t i t r a t i ~ n .~ ~ ~ L. Meitesclaims 242 that comparison shows that addition of sufficient excess of potas-sium iodide to retain cuprous iodide in solution is more satisfactory than themore usual method by which the iodide is precipitated. The increase incost is held to be offset by the greater speed and accuracy attained. Goldmay be titrated by using '' dithizone," and interference from other metalscan be o v e r ~ o m e . ~ ~ Alkaline aluminate solutions may be estimated by adouble titration with standard acid and standard potassium fluoride solu-tion.244 The iodometric determination of copper described by R. 0. Bras-ted 241 may be extended to deal simultaneously with the estimation of ironalso present in the solution.The titration of iron with perrnanganate onthe micro-scale has been found to be more satisfactory after reduction withstannous chloride than after use of the silver r e d ~ c t o r . ~ ~ ~ Conditions for theiodometric determination of iron(II1) have been established.246 Ferro-cyanide has been determined in the presence of cyanide by titration withcerium(1v),247 and ferricyanide can first be reduced by metallic mercury andthen titrated in the same way 248 since the presence of cyanide, or alternativelyof thiocyanate, enhances the reducing power of the mercury. The sameeffect can be utilised in the reduction of iron(m), and appears to have someadvantages over the use of amalgam reductors.Precipitated nickel di-methylglyoxime may be dissolved in acid, treated with excess of vanadatesolution, and back titrated with iron(I1) solution, phenylanthranilic acidbeing used as indicator.249 Nickel may also be oxidised by persulphate, andthe resulting compound estimated iodometrically.2m Chromium(m) oxid-z37 W. Rudorff and H. Zannier, 2. anal. Chem., 1952, 13'7, 1.238 V. K. Zolutukhin, J . Anal. Chem., U.S.S.R., 1951, 6, 246.239 M. M. Tillu, Analyt. Chem., 1952, 24, 1495.240 G. Denk, 2. anal. Chem., 1952, 138, 336.z41 R. 0. Brasted, Analyt. Chem., 1952, 24, 1040.243 L. Erdey and G. Rady, 2. anal. Chem., 1952, 185, 1.244 M. Beck and Z. G. Szab6, Analyt. Chim. Acta, 1952, 8, 316.245 M. C . Alvarez Querol, Miiirochenz. Mikrochim.Ada, 1952, 39, 126 ; F. de A. Bosch246 L. J. White, Coke and Gas, 1952, 14, 285.247 F. Burriel Marti, F. Lucena-Conde, and S. Bolle, Analyt. Chinz. Acta, 1952, 7, 302.248 F. Burriel Marti, Ind. Chem. Chem. Manuf., 1952, 28, 487.249 V. S. Syrokomsky and S. M. Gubelbank, J . Anal. Chem., U.S.S.R., 1951, 6, 207.*so E. S. Tomula, 0. Juutinen, and P. Tanskanen, 2. anal. Chem., 1952, 185, 265.242 Ibid., p. 1618.Arino and M. C . Alvarez Querol, Anal. veal SOC. es?. Fis. Quim., 1952, 48, B, 267WILSON INORGANIC TITRIMETRIC ANALYSIS. 317ation by mixed perchloric-sulphuric acids is more complete in the presence ofsilver nitrate,251 and the resulting chromium(v1) may then be estimatediodometrically without interference from precipitated silver iodide.The iodometric determination of tin has been reviewed, and a procedurerecommended.252 Bronzes may be dissolved in acid and reduced by antimonypowder, thus enabling the copper to be precipitated as cuprous thiocyanatebefore iodometric determination of tin(11) .253 Tin salts, when treated withsodium tartrate, liberate hydrogen ions which may then be estimated bytitration to a phenolphthalein end-point.254 Thorium may be precipitatedas molybdate 255 and the molybdate reduced and titrated, or by seleniousacid in the presence of ethanol 256 followed by an iodine-thiosulphatetitration.Thorium may also be titrated directly against standard oxalicacid, alizarin-S being used as an internal indicator.257 A direct titrationof vanadate solution using standard silver nitrate is possible, with an alcoholicgallic acid test-paper as indi~ator.~~8 Preliminary treatment and titrationconditions for the estimation of vanadium in steels,259 ferrovanadium,2m anduranium 261 have been described.Indicators and Related Topics-R.G. Bates 262 has discussed thedefinition of pH and the uncertainty in the value as measured, relating thisto the necessity for a more precise definition of the conditions of measurementthan is usually given. Methods have been described for the calculation ofthe pH of solutions.2m The desirable characteristics of an indicator havebeen discussed in terms of colour theory, and such processes as the screeningof indicators have been examined in the light of ideal behaviour.2m Colori-metric methods for the determination of pH have been described and dis-cussed. 26A method for stabilising litmus solutions over a period of a year hasbeen described.266 9-Ethoxychrysoidine adsorbed on silver iodide hasbeen recommended as an acid-base indicat0r.26~ The behaviour of arange of indicators with various compounds in chlorobenzene and othernon-aqueous solvents has been examined.268Investigation of a wide range of protective colloids for the retention ofsilver chloride in suspension, with dichlorofluorescein solution as indicator,has shown the best to be polyethylene glycol 400, a condensation productof ethylene oxide.26g The protective colloids usually recommended-dextrin251 S.Lynn and D. M. Mason, Analyt. Chem., 1952, 24, 1855.252 A. Doadrio, Inform.Quim. anal., 1952. 6, 79.253 M. L. Malaprade, Bull. SOC. chim., 1951, 18, 739.254 V. K. Zolutukhin, J . Anal. Chern., U.S.S.R., 1951, 6, 300.2 5 5 C. V. Banks, Iowa State Coll. J . Sci., 1951, 25, 145.256 G. S. Desmukh and L. K. Swamy, Analyt. Chem., 1952, 24, 218.257 P. Venkateswarlu and A. N. Ramanathan, Current Sci., 1952, 21, 45.258 M. Nivoli, Ann. Ghim., Roma, 1952, 43, 370.25n Methods of Analysis Committee, J . Iron Steel Inst., 1952, 171, 81.260 Idem, ibid., 170, 343.261 S. H. Simonsen, Analyt. Chim. Acta, 1952, 7, 33. a62 Analyst., 1952, 77, 653.263 J. Eeckhout, Analyt. Chim. A d a , 1952, 7, 203; A. J. McBay, J . Chem. Educ.,264 J . King, Analyst, 1952, 77, 742.265 T. B. Smith, C. A. White, P. Woodward, and P.A. H. Wyatt, J . , 1952, 3848;266 L. W. Cumming, J . Pharm. Pharmacol., 1952, 4, 324.267 E. Schulek and E. Pungor, Analyt. Chm. Acta, 1952, 7, 446.268 R. V. Rice, S. Zuffanti, and W. F. Luder, Analyt. C k m . , 1952, 24, 1022,26n R. B. Dean, W. C . Wiser, G. E. Martin, and D. W. Barnum, ibid., p. 1638.1952, 29, 526.R. H. &I. Simon, Analyt. Chem., 1952, 24, 1215318 ANALYTICAL CHEMISTRY.or gum arabic-may affect the end point significantly. Acid-violet 4BL 270and acid-red 6B 271 have been recommended as indicators for silver titrations.The systems iron(II1) with benzidine, tolidine, and a-dianisidine have beenfound satisfactory for the argentometric titration of bromides and iodidesa t great dilution 272 and for mercurous titration ofNaphthidinesulphonic acid 274, 275 and 3 : 3’-dimethylnaphthidinesul-phonic acid 274 have been recommended for a range of oxidation-reductiontitrations, and their oxidation potentials have been established.Rhodamine-B has been proposed as a fluorescent indicator in iodometric titrations withcoloured solutions,276 although in straightforward titrations sodium starchglycollate is to be preferred to any other indicator examined.Diphenylcarbazone screened with bromophenol-blue, which also permitsadjustment of pH,277 or with a nickel solution,278 has been recommended asan indicator in mercuric titrations of chloride. Alternatively, the chloridemay be treated with silver solution and mercuric solution, and diphenyl-carbazone is used to indicate the e n d - p ~ i n t .~ ~ ~ Conditions are describedfor the titration of zinc with ferrocyanide, diphenylthiocarbazone being usedas indicator.2@)6. CLASSICAL ORGANIC ANALYSIS.General.-General microchemical methods,281 volumetric methods inorganic analysis,282 the determination of metals in organicand the determination of organic functional groups 284 have been reviewed.The use of derivative melting points 285 and general precautions to be takenin the small-scale preparation of derivatives 286 have been discussed.Qualitative.-Methods have been proposed for the identification ofamides and nit rile^,^^^ carbonyl compounds,288 hydroxyquinones,290and steroids.291Quantitative.-H. Goldberger and M. Pohm 292 have described theweighing of hygroscopic liquid samples for combustion analysis.Stainless270 W. H. Weihe, Klin. Wochenschr., 1952, 30, 85.271 G. Mannelli and M. L. Rossi, Analyt. Chim. Acta, 1952, 6, 333.272 F. Sierra and J. HernSndez Cabavate, Anal. yea1 Soc. esp. Fis. Quim., 1952, 48,273 F. Sierra and J. A. SAnchez FernQndez, ibid., p. 339.274 R. Belcher, A. J. Nutten, and W. I. Stephen, J., 1952, 1269, 3857.276 G. W. C . Milner, Analyt. Chim. Acta, 1952, 6, 226.276 L. Deibner, Chim. anal., 1951, 33, 207.277 G. B. Smit, Analyt. Chtim. Acta, 1952, 7 , 330.278 J. S. Parsons and J . H. Yoe, ibid., 6, 217.279 J. Rodolfo Bayer, Anal. Asoc. Qulm. Argentina, 1951, 39, (193), 131.280 J. P. Mehlig and A. P. Guill, Analyt. Chem., 1951, 23, 1876.281 C. 0. Willits and C . L. Ogg, ibid., p.70.282 W. T. Smith and R. E. Buckles, ibid., p. 108.283 R. Belcher, D. Gibbons, and A. Sykes, Mikrochem. Mikrochim. Acta, 1952, 40, 76.284 A. J. Nutten, Ind. Chem. Chem. Manuf., 1952, 28, 273, 321; H. Lieb, Chimia,285 M. Brandstatter and H. Thaler, Mikrochem. Mikrochim. Acta, 1951, 38, 358.286 N. D. Cheronis and A. Vavoulis, ibid., p. 428.287 S. Soloway and A. Lipschitz, Analyt. Chem., 1952, 24, 898.288 L. Rosenthaler, Mikrochem. Mikrochim. Acta, 1952, 39, 360; C. Neuberg, A.Grauer, and B. V. Pisha, Anulyt. Chim. Acta, 1952, 7 , 238; J . J. Ritter and M. J. Lover,J . Amer. Chem. SOC., 1952. 74, 5576; G. Uttolino and M. Valente, Boll. SOC. ital. Biol.sper., 1951, 27, 446.290 J. R. Anderson, K. G. O’Brien, and F. H. Reuter, Amlyt. Chim. Acta, 1952, 7 , 226.H.Tauber, AnaZyt. Chem., 1962, 94, 1494.Ob2 Mikrochem. Mikrochim. Acta, 1962, 80, 73.B, 451, 457.1952, 6, 34.P. Clarke, Chem. and Ind., 1952, 450WILSON : CLASSICAL ORGANIC ANSLYSIS. 319steel has been proposed 293 as a material suitable for making absorption tubesfor semi-micro carbon-hydrogen determination. A. A. Sirotenko 294 reportsthat potassium persulphate should be mixed with the sample in carbon-hydrogen determinations on compounds containing alkali metals, in orderto prevent the formation of stable alkali carbonates, and magnesium oxidepellets have been used 295 to retain silicon tetrafluoride and other objection-able combustion products from fluorine-containing compounds. Standardmethods for carbon-hydrogen combustion have been modified by a numberof workers.296A furnace for use in the direct determination of oxygen has been de-scribed,297 and detailed accounts of the method have been given.298 Theimportance of proper preparation of the iodine pentoxide used for conversionof carbon monoxide into carbon dioxide in this determination has beens t r e s ~ e d .~ ~ ~ ~ 299Specifications have been drawn up for apparatus for the combustiondetermination of halogens and Modifications of the standardcombustion method for sulphur and halogens have been proposed.301 Arapid combustion method for these elements, using apparatus which followsthe general design of the rapid combustion method for carbon and hydro-gen,m2 has been de~cribed.~O~ A modified combustion method suitable forvery small amounts of sulphur has been proposed.304 The reactions resultingin the formation of silver sulphate in the sulphur determination 305 and thosetaking place in the decomposition of organic compounds with potassium 306have been examined.Decomposition with magnesium has been recom-mended for compounds containing sulphur and nitr~gen.~O' Wet oxidationmethods for sulphur compounds have been proposed, using potassiumchromate in phosphoric acid 308 or a nitric acid-hydrochloric acid mixturein the presence of sodium chloride with selenious acid as catalyst.309Specifications have been given for the apparatus for determination ofnitrogen by combustion,310 and modifications of the Dumas method have203 J. A. Kuck and M.Arnold, Mikrochem. Mikrochim. A d a , 1951, 38, 521.294 Ibid., 1952, 40, 30.296 W. H. Throckmorton and G. H. Hutton, Analyt. Chem., 1952, 24, 2003.206 S . S. Israelstam, Analyt. Chem.. 1952, 24, 1207; 0. G. Backeberg and S. S.Israelstam, ibid., p. 1209; G. De Vries and E. van Dalen, Analyt. Chim. Acta, 1952, 7,274; G. Kainz, Mikrochem. Mikrochirn. Acta, 1952, 39, 166; G. Mangeney, Bull. SOC.chim., 1951, 4, 809; V. A. Klimova and M. 0. Korshun, J . Anal. Chenz., U.S.S.R., 1951,6, 230; M. 0. Korshun, ibid., 1952, '7, 96; M. 0. Korshun and N. S. Sheveleva, ibid.,p. 104.287 A. Steyermark, M. J . McNally, W. A. Wiseman, R. Nivens, and F. P. Biava,Analyt. Chem., 1952, 24, 589.208 J. Unterzaucher, Analyst, 1952, 77, 584; I n d . Chem. Chem. Manuf., 1952, 28,492.208 E.G. Adams and N. T. Simmons, J . Appl. Chem., 1951, Suppl. 1, S 20.300 B.S.I. Specif., 1952, No. 1428, Pt. A3.301 E. D. Peters, G. C. Rounds, and E. J. Agazzi, Analyt. Chem., 1952, 24, 710;0. E. Sundberg and G. L. Royer, ibid., p. 907; G. W. Perold, S. Afr. I n d . Chem., 1951,5, 135. 302 R. Belcher and G. Ingram, Analyt. Chim. Acta, 1950, 4, 118.303 Idem, ibid., 1952, 7, 319.304 F. Grassner, 2. anal. Chem., 1952, 135, 186.306 M. 0. Korshun, J . Anal. Chem., U.S.S.R., 1952, 7, 101.306 G. Kainz and A. Resch, Mikrochem. Mikrochim. Acta, 1952, 30, 75.307 P. N. Fedoseev and N. P. Ivashova, J . Anal. Chem., U.S.S.R., 1952, 7, 112, 116.308 D. Koszegi and J. Barcsay, 2. anal. Chem., 1952, 135, 349.A. Steinbergs, J . Aust. Inst. Agvic.Sci., 1961, 17, 3, 166.alo B.S.T. Specif., 1952, No. 1425, Pt. A2320 ANALYTICAL CHEMISTRY.been proposed.311 The reactions taking place in the Dumas method havebeen discussed in some detai1312 and means of avoiding errors have beensuggested.313W. Kirsten3lP has described apparatus for the Kjeldahl method fornitrogen, and catalysts for the digestion process have been examined.315Reduction before digestion may be achieved by zinc and methano1316 orthiosalicylic acid.317 In describing a diffusion microgram method fornitrogen, B. W. Grunbaum, F. L. Schaffer, and P. L. Kirk31* point outthat, in spite of the mass of empirical information about the Kjeldahldigestion process, little fundamental information regarding it is available.Their experiments show that digestion in a sealed tube without a catalystis quite satisfactory provided that the temperature is not allowed to riseabove 450°, a t which temperature the sulphuric acid begins to oxidise theammonia with consequent loss.A diffusion method is also proposed byD. Seligson and H. S e l i g ~ o n . ~ ~ ~ M. Marzadro 320 shows how it is possible,by utilising the selective action of the Kjeldahl method together with theDumas method, to distinguish between nuclear and extra-nuclear nitrogenin heterocyclic compounds.The determination of phosphorus after decomposition in the Parr bombhas been described.321 Halogens have been determined by combustion,322by potassium by peroxide decornp~sition,~~ and by a modificationof Viebock’s method.325 Acid chlorides have been estimated by argento-metric titration in acetone s0lution,~26 aliphatic halogens on aromatic side-chains by hydrolysis with alkali in ethylene glycol solution,327 and halogencompounds have been reduced by hydrogen with a nickel catalyst in anaqueous-e t hanolic all<alisolu tion.328The reaction velocities of organic halides with mines have been claimedto have diagnostic value in the identification and determination of mono-halides and in the identification of more complex substances.329 Iodinemay be determined by reduction with zinc powder in sodium hydroxidesolution, followed by titrimetric determination of the iodide.330 The lead311 W. C. Alford, Analyt. Chern., 1952, 24, 881; H. Swift and E. S. Morton, Analyst,1952, 77: 392; H.Gysel, Helv. Chim. Acta, 1952, 35, 802; W. Schoniger, Mikrochem.Mikrochzm. Acta, 1952, 39, 229.312 Sheau-Shya Kao and W. C. Woodland, ibid., 1951, 38, 309; W. Kirsten, ibid.,1952, 39, 389.313 Idem, ibid., p. 245; H. A. Page1 and I. J. Oita, Analyt: Chem., 1952, 24, 756.314 Ibid., p. 1078.316 A. Mallol, Anal. real SOC. esp. Fis. Quinz., 1951, 47, B, 659; S. Dahl and R.Oehler, J . Amer. Leather Chern. Assoc., 1951, 46, 317 ; G. Middleton and R. E. Stuckey,J . Pharm. Pharmacol., 1951, 3, 829; G. N. Badami and J. W. Whitaker, Fuel, London,1951, 30, 211.316 V. B. Fish, Analyt. Chern., 1952, 24, 760.317 P. McCutchan and W. F. Roth, ibid., p. 369.318 Ibid., p. 1487. 31D J. Lab. Clin. Med., 1951, 38, 324.320 R.C. I s t . sup. Sanit., 1951, 14, 668; Mikrochenz. Mikrochim. Acta, 1951, 38, 372.321 W. Perkow and H. Koddesbusch, 2. anal. Chem., 1952, 136, 189.322 W. Kirsten and I. Alperowicz, Mikrochern. Mikrochim. Acta, 1952, 39, 234.323 G. Kainz and A. Resch, ibid., p. 1 .324 Idem, ibid., p. 292.326 D. Klamann, Monatsh., 1952, 83, 719.327 F. Buscaronsand P. Mir, Analyt. Chim. Ada, 1952, 7, 185.323 A. K. Ruzhentseva and V. V. Kolpakova, J . Anal. Chem., U.S.S.R., 1951, 6, 223.328 G. Salomon, Analyst, 1952, 77, 1017.330 C. W. Ballard and S. Spice, J . Pharm. Pharmacol., 1952, 4, 322.325 A. J. Nutten, ibid., p. 355WITSON : INSTRUMENTAL METHODS. 32 1chlorofluoride method for the determination of flporine has been adapted toprovide a Volhard titration finish.331Oxalic acid may be titrated with permanganate at room temperaturein the presence of ferric a l ~ m .~ 3 ~ Tartaric acid has been determined bytreatment with excess of standard sodium vanadate solution and backtitration with standard iron(I1) solution.333 A method has been describedwhich is suitable for the simultaneous determination of aldehydes, ketones,and compounds such as a ~ e t a l s , ~ ~ ~ and methods for carbonyl compoundshave been critically e~amined.33~ The necessity for close tolerances on thestandard glass joints in methoxyl apparatus has been stressed.336 A modi-fication has been proposed for the van Slyke apparatus for determiningamino-groups in which carbon dioxide is used as a sweeping gas.337 Methodsfor the determination of reactive hydrogen have been reviewed.338A method of titration referred to as “ solubilisation titration ” has beenproposed for the analysis of binary mixtures which are not readily analysedby other methods.339 This is based on phase changes in the presence ofaqueous solutions of substances such as Teepol.Thus a hexane-octan-1-01mixture is titrated with hexane-Teepol-water either to the point where aclear isotropic mixture results or where an aqueous phase just begins todeposit. These phase changes are readily detected, and provide preciseend-points.7. INSTRUMENTAL METHODS.In a new edition of their book, H. H. Willard, L. L. Merritt, and J. A.Deanm present an up-to-date account of the more important branches ofinstrumental analysis, with full working descriptions of simple apparatusfor applying the methods.The single drawback, for British users of thebook, is that commercial models of apparatus described are of Americanorigin, but this does not prevent the book from being a very valuable labora-tory adjunct. Other reviews of instrumental operations in analyticalchemistry, with special reference to automatic operations 341 and to work inthe organic field,342 have appeared.R. H. Muller illustrates possible future developments by reference to somevery recent types of apparatus and the requirements which led to theirconstruction.Electroana1ysis.-Recent developments have been reviewed.343 Anindirect method for the determination of mixed halides has been devised344which is based on precipitation of the silver h;lides, solution of these inIn the paper already referred to331 R.Belcher, E. F. Caldas, and S. J. Clark, Analyst, 1952, 77, 602.332 G. E. Mapstone and J . W. Smith, Chem. and Ind., 1952, 856.333 G. G. Rao and H. Sankegowda, Current Sci., 1952, 21, 188.334 R. H. Buchanan, Austr. J . Appl. Sci., 1951, 2, 276.335 J . J . Perret, Helv. Chim. Acta, 1951, 34, 1531.336 R. L. Huang and F. Morsingh, Analyt. Chem., 1952, 24, 1359; C. A. Redfarn andD. R. Newton, Chem. and Ind., 1952,404,857; R. G. Stuart, ibid., p. 520; W. McCorkin-dale and A. C. Syme, ibid., p. 758; G. Weston, ibid., p. 1059.337 A. S. Hussey and J . E. Maurer, Analyt. Chenz., 1952, 24, 1612.338 E. D. Olleman, ibid., p. 1425.339 E. C. Lumb and P.A. Winsor, Analyst, 1952, 77, 1012.340 “ Instrumental Methods of Analysis,” 2nd edtn., New York, 1951.341 G. D. Patterson and G. Mellon, Analyt. Chern., 1952, 24, 131.342 R. L. Peck and P. H. Gale, ibid., p. 116.343 S. E. Q. Ashley, ibid., p. 91. 344 R. Fort, Chinz. atzalyt., 1952, 34, 143.REP.-VOL. XLIX. 322 ANALYTICAL CHEMISTRY.cyanide solution, and electrochemical deposition of the silver. Electro-deposition methods have been described for the determination of copper inf e r r o t i t a n i ~ m , ~ ~ ~ and of copper and silver in alloys containing the twometalsu6 Manganese can be deposited on a mercury cathode from aqueoussolution and thus estimated.347 Plutonium can be electrodeposited onplatinum. 348Controlled potential analysis has been applied to copper-base alloys 349and to mixtures of copper, bismuth, lead, and tin.350 Internal electrolysishas been used for the determination of copper in stee1.351Coulometry and Related Methods.-In a general consideration of theapplication of polarisation curves to electrochemical processes, the use ofthese curves and other factors in deducing conditions for coulometric andpotentiometric analysis is di~cussed.~5~ P.Delahay 353 has dealt with therelation between equilibrium potentials and the irreversibility of electrodeprocessed in relation to coulometric titrations. Coulometric methods havebeen developed for cerium(1v) , dichromate, permanganate, and vana-d i u m ( ~ ) , ~ ~ ~ iron(1r) and arsenic(rII) ,355 ~ilver,~5G thallium(1),357 manganese,35*and uranium.359 Titanium(1v) chloride has been recommended as anintermediate in coulometric titrations which provides a more powerfulcouple than those hitherto reported, and hence permits the method to bemore widely applied.3m Inner electrolysis has been applied on a time basisto the titration of manganese and other element~.~~l Low concentrations ofoxygen have been measured by the capacity of a cell in which the gassurrounds a platinum electrode to form one of thePo1arography.-Probably the most significant contribution to thisbranch is the new edition of the standard work by I.M. Kolthoff and J. J.Li11gane,~63 which is approximately doubled in size. Polarography has beenreviewed,364 and in a review of the polarography of organic compoundsJ.E. Page3G5 gives an excellent introduction to general aspects of thesubject. Theoretical aspects of polarographic currents have been dis-cussed.366 The application of square-wave polarography to the detection345 L. Bonnafous, Chim. analyt., 1952, 34, 176.346 H. Diehl and J . P. Butler, Analyst, 1952, 77. 268.s47 B. McDuffie and L. S. Hazlegrove, AnaZyt. Chein., 1952, 24, 826.34* H. W. Miller and R. J. Brouns, ibid., p. 536.349 G. W. C. Milner and R. N. Whittem, Analyst, 1952, 77,.11.350 J. J. Lingane and S. L. Jones, Analyt. Chem., 1952, 24, 1798.3 5 1 D. L. Carpenter and A. D. Hoplcins, Analyst, 1952, 77, 86.352 R. Gauguin, G. Charkit, and J . Coursier, Analyl. Chim. Acta, 1952, 7, 172;R. Gauguin, G. Charlot, C.Bertin, and J . Badoz, ibid., p. 360; R. Gauguin and G.Charlot, ibid., p. 408; R. Gauguin, Ind. Chem. Chem. Manuf., 1952, 28, 487.364 L. Meites, Analyt. Chem., 1952, 24, 1057. 353 Analyt. China. Acta, 1952, 6, 542.355 W. M. MacNevin and B. B. Baker, ibid., p. 386.356 S. S. Lord, R. C. O'Neill, and L. B. Rogers, ibid., p. 209.357 R. P. Buck, P. S. Farrington, and E. H. Swift, ibid., 1195.3 5 8 W. D. Cooke, C. N. Reilley, and N. H. Furman, ibid., p. 205.359 N. H. Furman, C. E. Bricker, and R. V. Dilts, Nucleay Sci. Abstr., 1952, 6, 179.360 P. Arthur and J. F. Donahue, Analyt. Chenz., 1952, 24, 1612.361 A. Schleicher, 2. anal. Chem., 1952, 136, 330; W. Oelsen, H. Haase, and G.362 P. Hersch, I n d . :hem. Chem. Manuf., 1952, 28, 488.363 " Polarography,364 J.A. Lewis, Ind. Chem. Chem. Manuf., 1952, 28, 531.365 Quart. Reviews, 1952, 6, 262.366 P. Delahay and G. L. Stiehl, J . Anzer. Chem. SOC., 1952, 74, 3500; P. Delahay,ibid., p. 3506; P. Delahay and T. J. Adams, ibid., p. 5740; S . L. Miller, ibid., p. 4130.Graue, Angew. Chem., 1952, 64, 76.2nd edtn., New York and London, 1952WILSON : INSTRUMENTA4L METHODS. 323and determination of very low concentrations of ions, of the order of lo-'to l O W 9 ~ , has been described.367 W. Furness 365 has discussed the desir-ability of more precise measurement of the diffusion current and potential ofthe dropping-mercury electrode, and has suggested methods by which thismay be achieved. Recording apparatus suitable for polarography has beendescribed.369 J.Heyrovsky 370 has instanced advantages of using a cathode-ray oscilloscope for qualitative analysis by means of potential-time curves.A rotating mercury electrode which combines advantages of the dropping-mercury and of the rotating-platinum electrode, though with certain con-sequent disadvantages, is stated371 to be applicable to the analysis ofmaterials at very low concentrations. A method of differential polaro-graphy using a single dropping electrode has been proposed.372Individual polarographic methods have been proposed for the deter-mination of fluoride by complexing with aluminium and estimation of theexcess of aluminium,373 of sulphate by conversion into cadmium sulphideand determination of cadmium,374 of t e t r a t h i ~ n a t e , ~ ~ ~ of potassium byprecipitation with excess of dipicrylamine,376 of germanium,377 of copper-baseof copper by excess ofquinaldinic acid,381 of silver,382 of indium,383 of iron,384 of chromium,385of molybdenum,386 and of titanium.387388and polarographic methods of determination have been proposed fora ~ r a l d e h y d e , ~ ~ ~ f~rmaldehyde,~~ and glucose.391 Polarographic studieshave been made of some heterocyclic nitrogen compounds392 and somedyes.393 G.E. 0. Proske 394 has proposed the use of certain wetting agentssuch as the dialkyl sodium sulphosuccinates, which have little effect onpolarographic waves, for the solubilisation of organic compounds which areinsoluble in water, thus enabling polarographic determinations to be carried367 G.C. Barker and I. L. Jenkins, Analyst, 1952, 77, 685. 368 Ibid., pp. 246, 345.360 E. B. ThomAs and R. J . Nook, J , Chem. Educ., 1952, 29, 414; M. T. Kelley andH. H. Miller, Nuclear Sci. Abstr., 1952, 6, 148; Analyt. Chenz., 1952, 24, 1895.370 I n d . Chem. Chem. Manuf., 1952, 28, 489.371 T. S. Lee, J . Amer. Chem. SOC., 1952, 74, 5001.372 M. Ishibashi and T. Fuginaga, Bull. Chem. SOC. Japan, 1952, 25, 68.373 B. J. MacNulty, G. F. Reynolds, and E. A. Terry, Nature, 1952, 169, 888.374 A. D. Horton and P. F. Thomason, Analyt. Chem., 1951, 23, 1859.376 W. Furness and W. C. Davies, Analyst, 1952, 77, 697.376 D. Monnier and Z . Besso, Analyt. Chim. Acta, 1952, 7, 380.377 D. Cozzi and S. Vivarelli, Mikrochem. Mikrochim. Acta, 1952, 40, 1378 W.E. Allsopp and T. E. Arthur, Analvt. Chem., 1951, 23, 1883.37s F. Burriel Marti and J. F. Saiz del Rio, Anal. real SOC. esp. Fis. Quiun., 1951,380 0. I. Milner, J. R. Glass, J. P. Kirchner, and A. N. Yurick, Analyt. Chem., 1952,382 G. C. B. Cave and D. N. Hume, Analyt. Chem., 1952, 24, 588.383 G. Rienacker and E. Hoschek, 2. anorg. Chem., 1952, 268, 260.384 L. Meites, Analyt. Chern., 1952, 24, 1374.385 E. C. Mills and S. E. Hermon, Metallurgia, 1951, 44, 327.386 M. G. Johnson and R. J . Robinson, Analvt. Chem., 1952, 24, 366.387 R. P. Graham and A. Hitchen, Analyst, 1952, 77, 533.388 S. Wawzonek, Analyt. Chern., 1952, 24, 32.38s A. S. Kirillova and I. A. Korshunov, J . Anal. Chem., U.S.S.R.. 1951, 6, 257.3s0 A. S. Bogorad and S.N. Aleksandrov, ibid., p. 276.301 R. N. Adams, C. N. Reilley, and N. H. Furman, Analyt. Chewz., 1952, 24, 1200.302 R. C. Kaye and H. I. Stonehill, J., 1952, 3240.303 Idem, ibid., pp. 3231, 3244.of trace elements in lead379 and inRecent developments in organic polarography have been47, B, 803.24, 1728.P. E. Wenger, D. Monnier, and L. Epars, Helv. Chirn. Acta, 1952, 35, 561.3 ~ ~ 4 Analyt. Chem., 1952, 24, 1834324 ANALYTICAL CHEMISTRY.out. A polarographic study of certain metal salts and a number of acidchlorides in non-aqueous solution has been carried out, and the difficultiesnormally encountered in such work have been discussed.395Methodshave been proposed for the determination of fluoride through a decrease inthe diffusion current from an aluminium-organic for the deter-mination of iodine,Z98 of potassium with sodium dipi~rylaminate,~~~ and ofzinc with potassium ferr0cyanide.mPotentiometric Titrations.-The mechanism of the dead-stop end-pointhas been discussed,M1 and it has been shown that the method ought to beapplicable to any oxidation-reduction system by choosing suitable con-ditions. G.Granm2 has described a method, applicable to all types ofpotentiometric titrations, by which end-points which are not normally well-defined may be represented precisely by transforming the curves intointersecting straight lines. E. Bishopm3 has proposed the use of “ in-dicator-reference ” electrodes, thus simplifying the apparatus in potentio-metric titrations, and has extended the method to deal with non-aqueousas well as aqueous solutions.Peroxides have been determined iod~metrically.~~ Small amounts ofchloride have been estimated by making use of two half-cells which differonly in the chloride content due to the unknown 405 or by precipitating thechloride with iodide as carrier, the iodide being removed before titration.w6The errors involved in the potentiometric titration of mixtures of halideswith silver nitrate have been studied.” Methods have been proposed forthe argentometric titration of mixtures of bromides and thiocyanates,408 forthe mercurimetric titration of bromide,409 for the cerimetric titration ofhypophosphate,*1° for the estimation of phosphate by precipitation as zincphosphate and titration of the acid liberated,411 of thiocyanate using a silverthiocyanate electrode,412 of rubidium and czsium as chlorides argento-metrically,f59 of magnesium by addition of excess of fluoride and titrationof the excess with ferric chloride,413 of cadmium by applying an empiricalfactor in the bromate-bromide titration of 2-o-hydroxyphenylbenzoxa-zo1e,161, 414 of copper in the presence of oxidising anions iod~metrically,~~~ ofAmperometric Titrations.-Recent work has been r e v i e ~ e d .~ ~ 6395 P. Arthur and H. Lyons, ibid.. p. 1422.396 H. A. Laitinen, ibid., p. 46; T. D. Parks, Analyt. Chim. Acta, 1952, 6, 653.397 C. R. Castor and J. H. Saylor, Analyt. Chem., 1952, 24, 1369.398 H. P. Kramer, W. A. Moore, and D. G. Ballinger, ibid., p. 1892.399 Y . Yasumori, Bull.Chena. SOC. Japan, 1951, 24, 107.400 A. L. Woodson, B. H. Johnson, and S. R. Cooper, Analyb. Chem., 1952, 24, 1198.401 K. G. Stone and H. G. Scholten, ibid., p. 671 ; J. E. B. Randles, I n d . Chem.Chem. Manuf., 1952, 28. 490.402 AnaZyst, 1952, 77, 661.404 E. W. Abrahamson and H. Linschitz, Analyt. Chem., 1952, 24, 1355.405 W. J . Blaedel, W. B. Lewis, and J. W. Thomas, ibid., p. 509.406 G. S. Spicer and J. D. H. Strickland. Analyt. Chim. A d a , 1952, 6, 493.407 H. Chateau and J. Pouradier, Compt. rend., 1952, 234, 623.408 C. Leon, ibid., 1951, 253, 170.409 F. Sierra and 0. Carpena, Anal. real SOC. esp. Fis. Quim., 1951, 47, B, 527.410 T. Moeller and G. H. Quinty, Analyt. Chem., 1952, 24, 1354.411 R. N. Bell, A. R. Wreath, and W. T.Curless, ibid., p. 1997.412 R. N. Parida, S. Aditya, and B. Prasad, J . Indian Chem. SOC., 1952, 29, 377.‘13 W. Mannchen, Metal Abstr., 1952, 19, 795.414 J. L. Walter and H. Freiser, Analyt. Chem., 1952, 24, 1985.415 J. Bernal Nievas and L. Serrano Berges, Anal. real SOC. esp. Fis. Quim., 1951,403 Ibid.. p. 672.47, B, 601WILSON INSTRUMENTAL METHODS. 325manganese, chromium, and vanadium in steels,416 of chromium and iron inchromite ores,*17 of iron(1Ir) by titration with mercurous solution,41a oftungsten with chromous chloride,419 of uranium ~erimetrically,~~ and ofthorium as m ~ l y b d a t e . ~ ~ ~Conductance Methods.-In the last few years methods have been pro-posed for high-frequency titrations in addition to the normal methods forconductimetric titrations ; and high-frequency conductance measurementsare being used in ways other than titrimetric for analytical purposes.Asimple apparatus for conductimetric titration has been described.421 Aconductimetric titration method has been proposed for the determination offree acid in the presence of hydrolysable salts, and is applicable both tovery small aliquots of solution and to solutions of low concentration, so thatit is recommended for the titration of highly radioactive solutions.422 Thesulphate titration with barium solution has been studied, and it is pointedout 423 that the conductimetric end-point and the true equivalence-point arenot necessarily coincident, the former being affected by composition andconcentration of the solution. Such divergence should be taken into accountin precise work.Potassium perchlorate titrations are suitable for con-ductance measurements.& A method is described by which calcium andstrontium occurring together may be determined by conductance measure-ment, without titrati0n.4~~ R. P. Taylor and N. H. Furman426 havereported favourably on the possibility of using direct rather than alternatingcurrent for conductance measurements, and have devised an apparatus whichdoes not require either the specialised or inconvenient equipment necessaryfor alternating-current measurements. The accuracy and precision of thisapparatus, as applied to several different conductimetric determinations,compare favourably with those of the more normal methods.Theoretical and practical aspects of chemical analysis by high-frequencyconductance measurements have been discussed.427 P.W. West has de-scribed an apparatus suitable for both titrimetric and concentration deter-m i n a t i o n ~ , ~ ~ ~ and simple apparatus which could be set up and maintainedin the ordinary laboratory has also been de~cribed.~29 The high-frequencytitration of sulphates 430 and of calcium 431 has been reported.Colorimetry and Absorptiometry.-A new edition of a standard work hasappeared.432 General colorimetric methods have been reviewed.433 A416 F. Burriel Marti and R. Su&rez Acosta, Inform. Quirn. anal., 1951, 5 , 159; P.41' D. ZivanoviC, Bull. SOC. chim. Belgrade, 1951, 16, 151.418 R. Belcher and T.S. West, Analyl. Chinz. Acta, 1952, 7, 470.4lD S. E. S . El Wakkad and H. A. M. Rizk, Analyst, 1952, 77, 161.420 R. B. Hahn and M. T. Kelley, Nuclear Sci. Abstr., 1952, 6, 211.421 R. Weiner and L. Koller, 2. anal. Chem., 1952, 138, 241.422 L. P. Pepkowitz, W. W. Sabot, and D. Dutina, Analyt. Chent., 1952, 24, 1956.423 D. Lydersen and 0. Gjems, 2. anal. Chem., 1952, 137, 189.424 R. Weiner and L. Koller, ibid., p. 246.425 G. 0. Assarsson and A. Balder, Analyt. Chem., 1952, 24, 1679.426 Ibid., p. 1931.427 W. J . Blaedel, T. S. Burkhalter, D. G. Flom, G. Hare, and F. W. Jensen, ibid.,p 198; J . L. Hall, ibid., p. 1236; W. J . Blaedel, H. V. Malmstadt, D. L. Petitjean, andW. K. Anderson, ibid., p. 1240. 420 Ind. Chem. Chem. Manuf., 1952, 28, 492.429 J .L. Hall, Analvl. Chem., 1952, 24, 1244.430 0. 1. Milner, ibid., p. 1247. 431 S. Musha, Sci. Rep. TGhoku, 1951, A , 3, 56.432 B. Lange, " Kolorimetrische Analyse," 4th edtn., Weinheim, 1952.433 M. G. Mellon, Analyt. Chein., 1952, 24, 924; E. Geffroy, Chim. analyt., 1962, 34, 119.Enghag, J . Iron Steel Inst., 1952, 171, 443326 ANALYTICAL CHEMISTRY.capillary colorimeter for very small amounts of material 434 and a photo-electric comparator have been d e s ~ r i b e d . ~ ~ Means of improving precisionhave been suggested,436 and the fallacy of assuming that addition of a knownamount of constituent to a trace sample will improve the precision bybringing the final amount out of the region of high relative analysis errorhas been pointed Methods of dealing with two-component coloursystems 438 and with turbid solutions 439 have been discussed.Filters for themercury lines have been described,* and alkaline potassium chromate hasbeen recommended as a transmittancy standard for work in the ultra-violet .ulAbsorptiometric methods of analysis have been put forward for alloys 442and for trace metals in petroleum fraction^.^^ Individual analyticalmethods have been described for fluoride by its bleaching effect on variouslakes,P44 for hydrazine by $-dimethylarninoben~aldehyde,~~ for high nitratecontent by phenoldisulphonic acid,446 for phosphorus as molybdate 4479or as vanadate-m~lybdate,~~ for arsenic as m ~ l y b d a t e . ~ ~ , 451Oxygen in metallic tin is estimated by removing the metal with mercuryand estimating the tin in the residual oxide by phosph~molybdate,~~~ andgaseous oxygen is determined by the colour given with alkaline pyrogall01.~~~Metal sulphide sols have been examined for the estimation of sulphur, and amethod for preparing a satisfactory bismuth sulphide sol is given.454 Sulphurmay also be estimated by conversion into methylene-blue 455 or into Lauth'sviolet .456 Colorimetric procedures have been described for selenium andtellurium,233 for cyanide by reduction of sodium p i ~ r a t e , ~ ~ ~ and for boronby 1 : l-dianthraq~inoylamine,~~8 q ~ i n a l i z a r i n , ~ ~ ~ or pentamethylquer-434 G.Gorbach, Mikrochem. Mikrochim. Acta, 1952, 39, 204.435 T. I;. Stanton, Fuel, London, 1951, 30, 208.438 F.F. Pollak and J . W. Nicholas, Metallurgia, 1951, 44, 319.437 W. A. E. MacBryde, Analyt. Chem., 1952, 24, 1639.03* E. Allen and E. M. Hammaker, ibid., p. 1295; R. G. Milkey, ibid., p. 1675.439 J . Fog, Analyst, 1952, 77, 454.440 J. W. Nicholas and F. F. Pollak, Analyst, 1952, 77, 49; J . Chance, E. Guillemot,J . Lenoble, and G. Tendron, Compt. rend., 1951, 233, 35.44l G. K. Haupt, J . Opt. SOC. Amer., 1952, 42, 441.442 G. W. C. Milner and W. R. Nall, Analyt. Chim. A d a , 1952, 6, 420; M. Jean, ibid.,7, 338.443 J . H. Karchmer and E. L. Gunn, Analyt. Chant., 1952, 24, 1733.444 A. D. Horton, P. F. Thomason, and F. J . Miller, ibid., p. 548; M. J . Price and0. J . Walker, ibid., p. 1593; H. E. Bumsted and J . C. Wells, ibid., p. 1595.445 G.W. Watt and J . D. Chrisp, ibid., p. 2006.446 J. M. Komarmy, W. J. Broach, and M. K. Testerman, Analyt. Chim. Acta, 1952,7, 349.447 G. R. Nakamura, Analyt. Chem., 1952, 24, 1372.448 W. Teichert, J . Iron Steel Inst., 1952, 170, 181.449 S. Gericke and B. Kurmies, 2. anal. Chem., 1952, 137, 15.450 J . .C. Bartlet, M. Wood, and R. A. Chapman, Analyt. Chem., 1952, 24, 1821 ;C. Wadelin and M. G. Mellon, Analyst, 1952, 77, 708; Y . Kakita, Sci. Rep. Tdhokzt,1951, 3, A , 698.451 W. C. Coppins and J . W. Price, Melallurgia, 1952, 46, 52.452 L. Silverman, Nuclear Sci. Abstr., 1952, 6, 145.453 C. H. Blachly and R. R. Miller, Anal. Chem., 1952, 24, 1819.4S4 E. Treiber, H. Koren, and W. Gierlinger, Mikrochem. Mikrochim. Acta, 1952,40, 32.455 M. S.Budd and H. A. Bewick, Analyt. Chem., 1952, 24, 1536.456 D. S. C. Polson and J. D. H. Strickland, A n d y t . Chim. Acta, 1952, 6, 452.457 F. B. Fisher and J . S. Brown, Analyt. Chem., 1952, 24, 1440.468 D. A. Brewster, ibid., 1951, 23, 1809.459 D. MacDougall and D. A. Biggs, ibid., 1952, 24, 566WILSON : INSTRUMENTAL METHODS. 327~ e t i n . ~ ~ O Silicon may be determined as ~ilicomolybdate,~~~~ 462 and ger-manium with q~inalizarin.~63Methods for the determination of potassium have been reviewed,464 andmethods based on chloroplatinate 465 and silver cobaltinitrite 466 have beendescribed. Methods for the determination of sodium have been reviewed.467Colorimetric methods for calcium using m u r e ~ i d e , ~ ~ ~ chloranilic 470or the reaction of oxalate with diphenylamine to give aniline-blue 471 havebeen examined.Methods for beryllium use a l ~ m i n o n , ~ ~ ~ acetylacetone,62or r n ~ r i n . ~ ~ ~ Magnesium has been estimated by using Eriochrome-cyanine-R(Solochrome-cy anine-RS) ,474 Tit a n - y e l l ~ w , ~ ~ ~ ~ 47 3-hydroxy- 1 -$-nit rophenyl-3-~henyltriazen,~~~ 8-hydro~yquinoline,~~~ or the complex formed by8-hydroxyquinoline and iron.47s Zinc has been determined by o-[a-(2-hydroxy-5-sulphophenylazo) benzylidenehydrazino] benzoic acid.479 Forcadmium 480 and mercury 481 diphenylthiocarbazone has been used. Mercuryhas also been determined by its effect on the colour of ferric thiocyanatesolution.482Copper has been estimated as tartrate,4m by diethyldithio~arbamate,~~by rubeanic a ~ i d , 4 ~ ~ and by biscyclohexanone oxalyldihydrazone ; 486 silverby $-dimethylaminobenzylidenerhodanine ; 487 gold by diphenylamine 488 orby diphenylthiocarbazone ; 243 aluminium by Eriochrome-cyanine-R,4s9by $-hydroxyquinoline,4~~ 491 or by aluminon ; 402 manganese as per-460 M.K. Urs and K. Neelakantarn, J . Sci. I n d . Res., India, 1952, 11, B, 259.461 J . R. Boyd, Analyt. Chem., 1952, 24, 805.462 A. B. Carlson and C. V. Banks, ibid., p. 472.u3 C. K. N. Nair and J. Gupta, J . Sci. I n d . Res., India, 1951, 10, B, 300; 1952, 11,465 R. E. Eckel, J . Bzol. Chem., 1952, 195, 191.466 E. M. Chenery, Analyst, 1952, 77, 102.4 6 7 T. S. West, I n d . Chem. Chem. Manuf., 1952, 28, 225.468 H. Ostertag and E. Rinck, Compt. rend., 1951, 232, 629; Chinz. analyt., 1952, 34,4G0 F.Koroleff, Suomen Kem., 1951, 60, 56.470 R. F. U. Frost-Jones and J . T. Yardley, Analyst, 1952, 77, 468.4 7 1 J . de la Rubia Pacheco and F. Blasco L6pez-Rubio, Inform. QuCm. analit., 1952,473 T. Y. Toribara and P. S. Chen, ibid., p. 539.474 A. Bacon, Metallurgia, 1951, 44, 207.4 7 5 0. Glemser and W. Dautzenberg, 2. anal. Chem., 1952, 136, 254; A. C. Mason,4 7 0 K. N. Pochinok and V. Y. Pochinok, J . Anal. Chem., U.S.S.R., 1951, 6, 288.4 7 7 J. Davidson, Analyst, 1952, 77, 263.4 7 8 R. Bittel, Ann. nut. Inst. rech. Agron., 1951, 1, A , 144.470 J. H. Yoe and R. M. Rush, Analyt. Chim. Acta, 1952, 6, 526.480 L. Silverman and K. Trego, Anal-wt, 1952, 77, 143.481 D. J. S. Gray, ibid., p. 436. 482 R.0. Brumblay, Analyt. Chem., 1952, 24, 905.483 M. Bobtelsky and C. Heitner, Bull. SOC. chim., 1951, 18, 502.484 J. L. Hague, E. D. Brown, and H. A. Bright, J . Res. Nut. Bur. Stand., 1951, 47,485 A. Lemoine, Analyt. Chim. A d a , 1952, 6, 528; W. L. Miller, M. Acampora, and4 8 6 C. U. Wetlesen and G. Gran, Svensk Pappevstidning, 1952, 55, 212.4 8 7 G. C. B. Cave and D. N. Hume, Analyt. Chem., 1952, 24, 1503; E. B. Sandell and488 P. A. Heredia and J. C. Cuezzo, Monit. Farm., 1951, 57, 361.489 L. C. Ikenberry and A. Thomas, Analyt. Chem., 1951, 23, 1806; A. Bacon,490 W. Sprain and C. V. Banks, Analyt. Chim. Acta, 1952, 6, 363.4B1 0. A. Kenyon and H. A. Bewick, Analyt. Chem., 1952, 24, 1826.492 C. L. Luke and K. C . Braun, ibid., p. 1120; C. L.Luke, ibid., p. 1122.B, 274. 464 T. S. West, I n d . Chem. Chem. Manuf., 1952, 28, 158.108; J . Raaflaub, 2. physiol. Chem., 1951, 288, 228.6, 40. 472 C. L. Luke and M. E. Campbell, Analyt. Chem., 1952, 24, 1056.A.R.E. Malling Res. Sta., 1951, 126.380; C. A. No11 and L. D. Betz, Analyt. Chem., 1952, 24, 1894.G. Norwitz, Metal Abstr., 1952, 19, 856.J. J. Neumayer, ibid., 1951, 23, 1863.AnaZvst, 1952, 77, 90328 ANALYTICAL CHEMISTRY.rnanganateJq6l, 4933 4949 or through permanganate by the starch-iodideblue ;Iron has been estimated as acetate 497 or t h i o ~ y a n a t e , ~ ~ ~ ~ 498, 499 or byS-hydroxyquinoline,m thioglycollic acid,493 1 : 10-phenanthrolineJ38~ 490, 5014 : 7-diphenyl-1 : 10-phenanthroline,502 1 : 2-dihydroxybenzene-3 : 5-disulphonic acid ; 503 cobalt as tartrate 483 or t h i o ~ y a n a t e , ~ ~ or by nitroso-Rsalt , 505 diphenylthiocarbazone, 506 peroxide-bicarbonate treatment,m7zsonitrosomalonylguanidine,64 ethylenediaminetetra-acetic acid,64 or 4-nitro-2-mercapt oacetamidophenol ; 129 nickel as tartrate 483 or with dimethylgly-oxime; 3 8 0 9 493, chromium as dichromate 509 or with diphenylcarb-azide ; 510 molybdenum by thiocyanateJal, 515 prot~catechualdehyde,~~~ or1 : 2-dihydroxybenzene-3 : 5-disulphonic acid ; 513 tungsten by treatmentwith thiocyanate and stannous chloride ; 514 uranium by thiocyanate 516 orby resacetophenone ; 517 tin by 4-methyl-] : 2-dimercaptobenzene (toluene-dithiol) stabilised by Teepol ; 518 lead by diphenylthiocarbazone ; 519titanium as pertitanate 498 or by thym01,~~ 1 : 2-dihydroxybenzene-3 : 5-disulphonic acid,a3 or chromotropic acid ; 521 zirconium by precipitation asphosphate and conversion into phosph~molybdate,~~~ by a l i ~ a r i n - S , ~ ~ ~ orby chloranilic acid ; 470 thorium by o-arsenophenylazo-2-naphthol-3 : 6-disulphonic acid ; 524 antimony as the iodoantimonite byand rhenium as tetraphenylarsonium errh hen ate."^^or403 G.W. C. Milner and H. Groom, Metallurgia, 1951, 44, 271.494 B.S.I. Specif., 1951, No. 1121, Pt. 23.495 N. M. Silverstone and D. W. D. Showell, Metal Ind., 1952, 80, 467.496 S. Tribalat, I. Pamm, and M. L. Jungfleisch, Analyt. Chim. Acta, 1952, 6, 142.497 W. Reiss, J. F. Hazel, and W. M. McNabb, Analyt. Chem., 1952, 24, 1646.498 H.Seiser, Ber. deut. keram. Ges., 1951, 28, 699.499 W. Teichert, J . Iron Steel Inst., 1952, 170, 181.500 A. G. Hamlin, J . Text. Inst., 1952, 43, T, 234.601 A. Gottlieb, Mikrochem. Mikrochim. A d a , 1952, 39, 176.502 G. F. Smith, W. H. McCurdy, and H. Diehl, Analyst, 1952, 77, 418.503 R. H. Beaumont, Nuclear Sci. Abstr., 1952, 6, 212.504 W. A. C. Campen and H. Geerling, Chem. Weekblad, 1952, 78, 193.‘05 W. Stross and G. Stross, Metallurgia, 1952, 45, 315.606 J . Mermillod, Metal Abstr., 1951, 19, 215.507 G. Telep and D. F. Boltz, Analyt. Chem., 1952, 24, 945.508 J. Haslam, F. R. Russell, and N. T. Wilkinson, Analyst, 1952, 77, 464; V. T.Chuyko, J . Anal. Chenz., U.S.S.R., 1951, 6, 297.609 E. Asmus, 2. anal. Chem., 1952, 135, 179.510 B.S.I.Specif., 1952, No. 1121, Pt. 24; Methods of Analysis Committee, J . IronSteel Inst., 1952, 170, 268; H . J . Cahnmann and R. Bisen, Analyt. Chem., 1952, 24,1341 : B. E. Saltzman, ibid., p. 1016.511 R. B. Henrickson and E. B. Sandell, Analyt. Chim. Acta, 1952, 7, 57; P. Karstenand J. H. C . van Mourik, Rec. Trav. chim., 1952, 71, 302.512 M. Y . Shapiro, J . Anal. Chem., U.S.S.R., 1951, 6, 371.613 J. H. Yoe and F. Will, Analyt. Chim. Acta, 1952, 6, 450.514 G. Gran, Svensk Papperstidning, 1951, 54, 764.516 F. Jungblut, Chim. analyt., 1951, 33, 248.516 C. E. Crouthamel and C . E. Johnson, Analyt. Chew., 1952, 24, 1780.517 M. K. Urs and K. Neelakantam, J . Sci. I n d . Res., India, 1952, 11. B, 79.518 F. R. Williams and J. Whitehead, J . Appl.Chem., 1952, 2, 213.519 F. Neuwirth, J . Iron Steel Inst., 1952, 170, 310.520 J. V. Griel and R. J. Robinson, Analyt. Chem., 1951, 23, 1871.521 T. C . J. Ovenston, C. A. Parker, and C. G. Hatchard, Anulyt. Chim. Acta, 1952,523 E. W. Kiefer and D. F. Boltz, Analyt. Chem., 1952, 24, 542.523 G. B. Wengert, ibid., p. 1449; A. Mayer and G. Bradshaw, Analyst, 1952,524 Idem, ibid., p. 154; A. E. Taylor and R. T. Dillon, Analyt. Chem., 1952, 24, 1624;6, 7 ; R. Rosotte and E. Jaudon, ibid., p. 149.77, 476.R. Kronstadt and A. R. Eberle, Nuclear Sci. Abstr., 1952, 6, 179WILSON INSTRUMENTAL METHODS. 329met hyl-violet ,525 or by triphenylmethylarsonium iodide ; 526 bismuth byt hic urea,527 cupferron ,528 or dial1 yldit hiocarb amidoh ydrazine ; 529 vanadiumas kanadyl ion,=() by catalytic liberation of iodine,%l as the complex phos-phoiungstic acid,380 or with benzhydroxamic acid; 632 niobium as thio-cyanate 533 or as perniobic acid; 634 osmium by thiourea; 197 rutheniumby p-nitrosodimethylaniline ; 535 rhodium by the blue complex formed withhypochlorite ; 536 and palladium with p-furfuraldoxime 537 or phenyl-thiourea. 538From the large number of colorimetric methods for organic compoundsthe following may be mentioned : determination of methanol by Schiff'sreagent ; 539 of acetic acid 5~ and glycerol by reduction of dichromate ;of nitroparaffins by decomposition, and combination of the resulting nitrousacid with resorcinol; 542 of amides through the reaction of the derivedhydroxam ic acids with ferric chloride.543 The system dichromate-chromium(111) has been studied with a view to its use for the colorimetricdetermination of sulphite and of organic compounds,"l, 545 and it hasbeen found to be very sensitive, particularly if absorptiometric measure-ments are carried out in the ultra-violet region. A similar indirect methodfor organic compounds depends on treatment by standard oxidising agentsfollowed by an oxidisable dye. The amount of oxidising agent used, andhence of organic compound, is determined by colorimetry of the residualdye. 5.1~Photometric tit rations have been proposed for bromide-bromate re-action~,"~ using the absorption of the tribromide ion to indicate the end-point, and absorptiometric methods have also been used to follow the titra-tion of arsenic by cerium(~v).~~* Luminol has been proposed as a chemi-luminescent indicator to enable detection of the end-point photometricallyin acid-base titrations of highly opaque solutions; M9 for example, by usingthis method it was possible to determine the end-point of the titration of asolution containing Indian ink.525 M.Jean, Analyt. Chim. Acta, 1952, 7, 462.526 B. Figgis and N. A. Gibson, ibid., p. 313.527 B. B. Bendigo, R. K. Bell, and H. A. Bright, J . Res. Nut. BUY. Stand., 1951, 47,628 H. Bode and G. Henrich, 2. anal. Chem., 1952, 135, 98.529 J . Gupta and K. P. S. Sarma, J . I n d i a n Chem. Soc., 1951, 28. 89.530 R. Santini, J. F. Hazel, and W. M. McNabb, Analyt. Chim. A d a , 1952, 6, 368.531 T.Shiokava, Sci. Rep. TGhoku, 1950, 2, A , 613.532 A. K. Das Gupta and M. M. Singh, J . Sci. I n d . Res., India, 1952, 11, B, 268.533 H. Freund and A. E. Levitt, Analyt. Chem., 1951, 23, 1813; A. B. H. Lauw-Zecha, S. S. Lord, and D. N. Hume, ibid., 1952, 24, 1169.534 G. Telep and D. F. Boltz, ibid., p. 163.535 J . E. Currah, A. Fischel, W. A. E. McBryde, and F. E. Beamish, ibid., p. 1980.536 G. H. Ayres and F. Young, ibid., p. 166.538 G. H. Ayres and B. L. Tuffly, ibid., p. 949.539 J . F. Guymon, J . Ass. Off. Apric. Chem., 1951, 34, 310.640 E. Ciaranfi and A. Fonnesu, Biochem. J . , 1952, 50, 698.541 D. T. Englis and L. A. Wollerman, Analyt. Chem., 1952, 24, 1983.542 L. R. Jones and J. A. Riddick, ibid., p. 1533.643 I;. Bergmann, ibid., p.1367.544 S. Sussman and I. L. Portnoy, ibid., p. 1652.545 M. J . Cardone and J . Compton, ibid., p. 1903.546 H. T. Gordon, ibid., 1951, 23, 1853.547 P. B. Sweetser and C. E. Bricker, ibid., 1952, 24, 1107.548 Idem, ibid., p. 409.549 1;. Kenney and R. B. Kurtz, ibid., p. 1218.252; C. J . Hall, Analyst, 1952, 77, 318.537 E. W. Rice, ibid., p. 1995330 ANALYTICAL CHEMISTRY.Nephelometry.-Chloride has been determined in titanium sponge byprecipitation as silver chloride followed by conversion into a silver sulphideZinc may be precipitated in a form suitable for nephelometricestimation by 8-hydro~yquinoline,~51 and tin(1v) by precipitation with4-hydroxy-3-nitrobenzenearsonic acid.552 A nephelometric titration hasbeen devised from the estimation of very small amounts of halides based onthe colour change at the end-point of the sol formed with silver nitrate.553F1uorimetry.-Fluorimetric analysis has been reviewed.554 Fluorescenttests have been described for h y d r a ~ i n e , ~ ~ ~ aluminium,556 lead,557 and8-hydroxyquinoline and its derivatives.558Quantitative methods depending on fluorescence have been proposed forfluoride,559 beryllium,560 and uranium. 561Emission Spectrography .-Advances in instruments and in analyticalmethods have been reviewed.562 R. C. Hughes has described a method ofapplying powdered samples to graphite electrodes in a reproducible man-ner.563 The line-width method of quantitative analysis has been applied toplant products so as to produce reproducible results over a wide range ofconcentration^.^^^ Methods of concentrating 565 and analysing 566 traceelements have been described, and spectroscopic analysis has been appliedto small amounts of impurities in tungsten,567 of metals in cracking cata-lysts 56* and in and to the analysis of coppers and brasses,570 oflanthanon mixtures 571 and of mixtures of the platinum m e t a l ~ .~ 7 ~For individual elements spectrographic methods have been recommendedfor the determination of lithium and rubidi~m,~74 l i t h i ~ m , ~ ~ jiron,576 lead,577 and tantalum and niobium.578 A spectrographic study has650 M. Codell and J. J. Mikla, Analyt. Chem., 1952, 24, 1972.651 L. Bertiaux, Chim. analyt., 1951, 33, 59.652 P. Karsten, H. L. Kies, and J . J .Walraven, Analyt. Chim. Acta, 1952, 7 , 355.553 M. Hasselmann and G. Laustriat, Compt. rend., 1952, 234, 625.554 C. E. White, Analyt. Chem., 1952, 24, 85; C. E. White et al., ibid., p. 1965.555 F. Feigl and W. A. Mannheimer, Mikrochem. Mikrochim. Acta, 1952, 40, 50.5 5 6 F. Feigl and G. B. Heisig, J . Chem. Educ., 1952, 20, 192.5 5 7 S. Slijivic, Bull. SOL. chim. Belgrade, 1951, 16, 147.5 6 8 F. Feigl, Mikrochem. Mikrochim. Acta, 1952, 39, 404.550 H. H. Willard and C. A. Horton, Analyt. Chem., 1952, 24, 862.660 H. A. Laitinen and P. Kivalo, Nuclear Sci. Abstr., 1952, 6, 69; Analyt. Chem.,561 M. D. Yeaman, Nuclear Sci. Abstr., 1952, 6, 104; N. S. Guttag and F. S. Grimaldi,662 W. F. Meggers, Analyt. Chem., 1952, 24, 23; R. L. Mitchell, Ind. Chem.Chem.663 Analyt. Chem., 1952, 24, 1406.564 R. T. O'Connor and D. C. Heinzelman, ibid., p. 1667.565 G. Gorbach and F. Pohl, Mikrochem. Mikrochim. Acta, 1951, 38, 328.566 Idem, ibid., p. 335; S. Wilska, Acta Chem. Scand., 1951, 5 , 1368.5 6 7 C . H. R. Gentry and G. P. Mitchell, Metallurgia, 1952, 46, 47.5 6 8 J . P. Pagliassotti and F. W. Porsche, Analyt. Chem., 1952, 24, 1403.560 A. J . Ham, J. Noar, and J . G. Reynolds, Analyst, 1952, 77, 766.570 F. V. Schatz, J . Inst. Met., 1951, 80, 77.571 J . A. Norris and C. E. Pepper, Analyt. Chem., 1952, 24, 1399.672 G. H. Ayres and E. W. Berg, ibid., p. 465; H. Oberlander, Metal Abstr., 1952, 19,573 A. B. Chandler, Brit. Ceram. Abstv., 1952, 107 A.574 A. Halperin and S. Samursky, J . Opt. SOC.Amel.., 1952, 42, 475.5 i 5 G. I. Stukenbroeker, D. D. Smith, G. K. Werner, and J. R. McNally, ibid., p. 383.5 7 6 J . E. Barney and W. A. Kimball, Analyt. Chem.. 1952, 24, 1548.5 7 7 V. Brustier, P. Cornec, and H. Triche, Compt. rend., 1952, 234, 2367.578 W. J . Poehlman and R. E. Sarnowski, J . Opt. SOL. Amer., 1952, 42, 489.1952, 24, 1467.ibid., p. 145; M. Nakanishi, Bull. Chem. SOC. Japan, 1951, 24, 33, 36.Manuf., 1952, 28, 491 ; J . K. Hurwitz, J . Opt. SOC. Amer., 1952, 42, 484.403; J. E. Hawley, W. J . Wark, C . L. Lewis, and W. L. Ott, ibid., p. 856WILSON INSTRUMENTAL METHODS. 33 1been made of the co-precipitation of vanadium with the hydroxides oftervalent metals. 579Improved flame photometers have been d e s ~ r i b e d , ~ ~ ~ 581 and an im-proved method for the flame analysis of plant ash has been devi~ed.~8~Individual flame photometric methods have been proposed for the elementsboron,5= lithi~m,~M 5869 587 potas~ium,~~~9 586 rubidi~m,~88 andcalcium,586~ 589 G.C. Collins and H. Polkinhome 581 have studied the effectof anions on the flame-photometric determination of sodium and potassium.An emission spectrographic method has been proposed for the deter-mination of halogen compounds. 590 In this, the emission spectrum excitedby a high-frequency electrodeless discharge has been used. Little workseems to have been done along these lines, and with modern apparatus itwould seern to the Reporter feasible to assume that the characteristic high-frequency spectra of many organic compounds, first studied many yearsago from a theoretical point of view,591 ought to be capable of considerableanalytical application.Absorption Spectra.-Analytical applications of absorption spectrain the visible and ultra-violet regions have been re~iewed.5~~9 593 Anelectrodeless hydrogen discharge tube as a source of ultra-violet continuumhas been described.594 The absorption spectra of substances may bemeasured as reflection spectra, and this has been utilised to identify materialson an adsorption c0lumn.~9~Infra-red spectroscopy has also been 596 A differentialmethod of analysis depending on the comparison of known and unknownsamples has been discussed theoretically, and possible sources of error havebeen e~amined.5~7 A simple infra-red absorption cell has been de~cribed.5~8A.E. Martin 599 has pointed out the potential value of a comprehensivecatalogue of infra-red spectra of organic compounds, and the ease withwhich this could be obtained, in a fairly complete form, within a reasonablyshort time, if workers were to co-operate in providing data according to ascheme which he outlines. Infra-red absorption studies of aromatic hydro-67Q F. Burriel Marti, E. Fernandez Caldas, and J. Ramirez Mufios, Anal. real SOC.680 J . U. White, AnaZyt. Chem., 1952, 24, 394; C. A. Dubbs, ibid., p. 1654; L. Leyton,582 F. H. Vanstone, A.R.E. Malling Res. Sta., 1951, 122.683 C. E. Bricker, W. A. Dippel, and N. H. Furman, Nuclear Sci. Abstr., 1952, 6, 212.684 L. H. Kalenowski and S. M. Runke, U.S.Bur. Mines, 1952, Rep. Invest., 4863.686 L. 1. Obolenskaya, Soils and Fert., 1951, 14, 449.6 8 6 R. Herrmann, 2. ges. exp. Med., 1952, 118, 187.6 8 7 S. B. Knight and M. H. Peterson, Analyt. Chem., 1952, 24, 1514.5 8 8 H. E. Freytag, 2. anal. Chem., 1952, 138, 161.68Q H. J . Hubener, 2. physiol. Chem., 1952, 289, 188.690 R. E. Keller and L. Smith, Analyt. Chem., 1952, 24, 796.6Q1 A. W. Stewart and C. L. Wilson, “ Recent Advances in Physical and Inorganic6Q2 0. D. Shreve, Analyt. Chem., 1952, 24, 1693.5Q3 M. G. Mellon, ibid., p. 2 ; E. J. Rosenbaum, ibid., p. 14.6Q4 G. H. Dieke and S. P. Cunningham, J . Opt. SOC. Amer., 1952, 42, 187.5Q5 F. Pruckner, M. van der Schulenberg, and G. Schwuttke, Naturwiss., 1951, 38,45.696 R. C. Gore, Analyt.Chem., 1952, 24, 8 ; N. Sheppard, Analyst, 1952, 7 7 , 7 3 2 ;R. C. Lord, R. S. McDonald, and F. A. Miller, J . Opt. SOC. Amer., 1952, 43, 149; A. E.Martin, Indust. Chem. Chem. Manuf., 1952, 28, 243.6n7 D. 2. Robinson, Analyt. Chem., 1952, 24, 619.5Q8 K. S. Tetlow, J. Sci. Insty., 1951, 28, 322. 6Dn Nature, 1952, 170, 20.esp. Fis. Qulm., 1952, 48, B, 59.Biochem J . . 1952, 50, Proc., xl. 681 Analyst, 1952, 77, 430.Chemistry,” 7th edtn., London, 1944, p. 452332 ANALYTICAL CHEMISTRY.barbiturate derivatives,m1 alkaloids,m2 and polymer degradationproducts 603 have been reported.F. A. Miller and C. H. Wilkins6e4 have discussed the use of infra-redabsorption spectra in the identification of inorganic polyatomic ions. Point-ing out that no systematic study has, up to the present, been made of thesespectra, and that little up-to-date information is available, they present, bothgraphically and in tabular form, the spectra of about 160 inorganic compoundswhich can be used, in conjunction with other methods of analysis, to provideuseful information about the composition of inorganic materials.Theprincipal drawback to more extended use of the method is the necessity €ordetermining the spectra from samples in powder form.Chemical Microscopy.-Hot-stages for work with the microscope havebeen described 605 and a method has been outlined for the determination ofboiling points and boiling ranges using such a hot-stage.m6 The use ofmixed melting points for the construction of phase diagrams has been dis-and a method has been described by which the techniques applic-able in such studies may be used for purification.m8 Fusion methodsaccompanied by crystallographic examination have been compared with themethods used for phase studies,609 and the former have been extended to theinorganic field by an examination of the fusion behaviour of a wide range ofinorganic compounds with 8-hydroxyquinoline.610A simple method has been described for determining the optic axial angleof crystals,611 and crystallographic data have been presented for lanthanumoxalate decahydrateJ612 ethylenedinitramine,613 2 : 4 : 6 : 2’ : 4’ : 6’-hexani-t rodiphen y lamine , l4 N-ace t yl-N’-phen ylh ydrazine, 61 pht halic anhydride, 616dibenzyl ~ u c c i n a t e , ~ ~ ~ s-diphenylcarbazide,618 ~-threonine,619 pseudotro-pine,G20 ( &)-mandelic acid,621 2 : 4-dinitrophen01,~~2 and 4 : 6-dinitro-resorcinol.623Nicotine thiocyanate has been found 624 to give crystalline precipitateswhich are suitable for identification under the microscope with a number ofcations. Crystal tests have been proposed for nitrate and nitrite usingp-aminophenylmercuric and for cobalt using potassium tri-600 R. B. Williams, S. H. Hastings, and J . A. Anderson, A n a l y t . Chem., 1952, 24. 1911.601 C. J . Umberger and G. Adams, ibid., p. 1309.602 G, Papineau-Couture and R. A. Burley, ibid., p. 1918.603 B. C. Achhammer, ibid., p. 1925.605 E. G. Steward, J. Sci. I n s t r . , 1952, 29, 214; W. Kofler, Mikrochem. Mikrochim.606 J .S . Wiberley, R. K. Siegfriedt, and A. A. Benedetti-Pichler, ibid., 1951, 38, 471.60’ L. Kofler, Z . anal. Chem., 1951, 133, 27.608 R. Fischer, Mikrochem. Mikrochirn. A c t a , 1951, 38, 342.60Q W. C. McCrone, ibid., p. 476.610 P. W. West and L. Granatelli, A n a l y t . Chem., 1952, 24, 870.6 1 1 A. J. Pollard, L. I. Braddock, and M. L. Willard, Mikrochem. Mikrochim. A c t a ,613 W. C. McCrone, ibid., p. 421.615 M. B. Williams and W. P. Van Meter, ibid., p. 762.616 M. B. Williams, W. P. Van Meter, and W. C. McCrone, ibid., p. 911.1 3 ~ 7 J . Krc, ibid., p. 1070.618 M. B. Williams, W. P. Van Meter, and R. J. Robinson, ibid., p. 1220.621 H. A. Rose, ibid., p. 1680.623 W. C. McCrone and I. Corvin, ibid., p. 2008.624 S, E. Burkat, E.N. Skrynnik, and S. S. Yaroslavskaya, J. A n a l . Chem., U.S.S.R.,604 Ibid., p. 1253.Ada, 1952, 39, 84; F. Hippenmeyer, ibid., p. 409.1952, 39, 192. 612 V. Gilpin and W. C. McCrone, A n a l y t . Chem., 1952, 24, 225.614 I d e m , ibid., p. 592.R. L. Clarke and J . Krc, ibid., p. 1378. 620 I d e m , ibid., p. 1516.622 W. C. McCrone and J . Krc, ibid., p. 1863.1951, 6, 325. 625 I. M. Korenman and A. A. Belyakov, ibid., 1952, 7, 52WILSON PHYSICAL SEPARATION METHODS. 333oxalatoferrate.626 Zirconium and hafnium may be distinguished by theproper application of the crystal test using quinoline and ammonium thio-~ y a n a t e . ~ ~ ~Miscellaneous Instrumental Methods.-X-Ray methods have beenreviewed.628 X-Ray spectra have been used for the quantitative analysisof minerals,629 and powder patterns have been used for the identification ofmolybdenum and tungsten oxides. 630The application of the mass spectrometer to analytical problems has beenreviewed and a simple pen recorder has been described.632 The massspectrometer has been applied to the analysis of hydrocarbons.633 Anextension of the use of the instrument for the analysis of non-volatilematerials, by examination of pyrolysis products obtained under controlledconditions, has been recommended.634 Various modes of pyrolysis havebeen investigated, and the method may be used, either for direct identificationin the simpler cases, or for identification by comparison with known samplesin the case of more complex materials.8.PHYSICAL SEPARATION METHODS.H. H. Strain and G. W. Murphy635 have reviewed what they term“ chromatography and analogous differential migration methods,” and anumber of other reviews of these methods have also appeared.636Any survey of this field leads to the conclusion that it will be many yearsbefore any coherent overall picture of the methods and their potentialitiescan be presented. The confusion in terminology which already exists seemsto become greater with the passage of time and with the formation of newsub-divisions, some of these unfortunately with rather slight justification.Among relatively new terms which have to be fitted into the complete pictureare “ gradient elution analysis,” 637 “ ionography,” “ papyrography,” 639“ ultra-violet papyrography, ” 640 even “ ultra-micro-papyrography ” 641(achieving a double distinction in that paper is not used in the separation, whichis achieved by means of cotton thread), “ electrokinetic ultrafiltration,” 642“ electrophoresis-convection,” 643 and “ chromathermography.” 64438, 466.626 J .C. Ryan, L. K. Yanowski, and M. Cefola, Mikrochem. Mikrochim. Acla, 1951,627 C. J . van Nieuwenburg and J . W. L. van Ligten, Analyt. Chim. Acta, 1962, 7, 390.628 H. A. Liebhafsky, Analyt. Chem., 1952, 24, 16; H. S. Kaufman and I. Fankuchen,829 G. Talvenheimo and J. L. White, ibid., p. 1784; M. Tournay, Compt. rend., 1952,630 A. Magneli, G. Anderson, B. Blomberg, and L. Kihlborg, Analyl. Chem., 1952,6ss H. Sobcov, ibid., pp. 1386, 1908; I. W.Kinney and G. L. Cook, ibid., p. 1391.634 P. D. Zemany, ibid., p. 1709. 635 Ibid., p. 50.636 A. Tiselius, Ewdeavour, 1052, 11, 5 ; G. B. Marini-Bettolo, Chiplz. e Ind., 1952, 34,269; Anon., Chem. Eng. News, 1952, 30, 4244.637 R. J . P. \Villiams. Analyst, 1952, 77, 905.638 H. J . McDonald, J . Chem. Educ., 1952, 29, 428.a39 M. K. Nayar and V. K. M. Rao, J . Sci. I n d . Res., India, 1952, 11, B, 78.640 Y. Hashimoto and I. Mori, Nature, 1952, 170, 1024.641 D. S. Venkatesh and M. Sreenivasaya, Current Sci., 1951, 20, 156.642 D. L. Mould and R. L. M. Synge, Analyst, 1952, 77, 964.643 D. M. Tennent and M. Kniazuk, Analyt. Chem., 1952, 24, 1661.ibid., p. 20.234, 2527.24, 1998. 631 V. H. Dibeler and J . A. Hipple, ibid., p. 27.K. K. Jensen, W. E.Bell, and F. E. Blacet, ibid., p. 1614.A. A. Zhukhovitsky, 0. V. Zolotareva, N. A. Sokolov, and N. M. Turkeltaub,Compt. rend. Acad. Sci., U.R.S.S., 1951, 77, 435334 ANALYTICAL CHEMISTRY.This multiplication of terminology is objectionable, merely on thegrounds stated earlier (p. 306). It is additionally objectionable here on twocounts : it increases the confusion regarding the causes of such separations,and it makes more difficult the recognition of really novel techniques.“ Chromatographic analysis ” has been soberly defined 1 as the “anaIysisof a solution by the use of solid sorbents such as paper or alumina, to separatesubstances in solution by selective sorption.” This definition tallies closelyenough with the terminology of H. H. Strain and G.W. Murphy G35 to meritacceptance. However, it does not seem to be sufficiently all-embracing forthe enthusiast, who continues to present us with other definitions whichare not so readily defensible. Thus T. I. Williams and H. Wei1,645 whileadmitting that “ so many processes are now by cummun consent accepted asforms of chromatography that an unequivocal definition of the word in itspresent chemieal sense presents difficulties,” have proposed that it be definedas “ those processes which allow the resolution of mixtures by effectingseparation of some or all of their components in concentration zones or inphases different from those in which they are originally present, irrespectiveof the nature of the force or forces causing the substance to move from onephase to another.’’ They claim that this definition embraces not only thevarious forms of chromatography hitherto achieved, but also all forms whichhave been postulated as theoretical possibilities.It -does this, of course,but it surely includes also such analytical operations as precipitation andsteam-distillation ; and in any case, common consent without criticaldiscussion is no ground for attempting to make “ chromatography ” thetouchstone-term for every new device, whatever its merits and whateverits mechanism.To provide a definition that does not define is only to add further con-fusion to an already overcrowded pattern. The word “ chromatography ”has, a t the present time, become one of the magic words-in the same classas “ resonance ” in the nineteen-thirties.The illusion exists that to give aprocess a name explains the process; and this in turn may lead to mis-interpretation of the causes which are operating in any separation, and to theconclusion that new causes have been observed when in fact they do notexist.Some of the dangers in this state of affairs seem likely to arise, for example,from the increased use of impregnated papers which has been reportedrecently. Papers impregnated with alumina,646 borate,647 and various otherinorganic salts,64* glycerol and various glycols, 6469 649 silicones, 650 phenyl-cellosolve,651 toluene-$-~ulphonate,~~~ and stearatochromic chloride 653 haveall been used. It is almost impossible, in some of these cases, to determineon the published information and in view of the little that is known about thesimpler separations, the mechanism by which the separations are taking place.646 Nature, 1952, 170, 503.646 I.E. Bush, Nature, 1950, 166, 445; Biochem. J . , 1952, 50, 370.647 C. A. Wachtmeister, Acta Chem. Scand., 1951, 5, 976.648 M. Lederer, Analyt. Chim. Acta, 1952, 7, 458.649 R. J . Boscott, Biochem. J., 1951, 48, Proc. xlvii; A. Zaffaroni, R. B. Burton, and660 T. H. Kritchevsky and A. Tiselius, Science, 1951, 114, 299.661 R. Neher and A. Wettstein, Helv. Chim. Acta, 1952, 35, 276.66z R. J . Foscott, Chem. and Ind., 1952, 472.663 D. Kritchevsky and M. R. Kirk, J. Amer. Chem. SOC., 1952, 74, 4484.E. H. Keutmann, Science, 1950, 111, 6 ; J . Biol.Chem., 1951, 188, 763WILSON PHYSICAL SEPARATION METHODS. 335That considerable caution must be used is stressed by the ease withwhich artefacts may appear in separations which are apparently quitestraightforward, as has been pointed out by a number of authors.654 Evensuch simple operations as acid-washing of paper 655 may produce a radicalchange in mechanism, while insufficient attention to water-content 656will certainly do so, and can lead to the anomalous result that a column ofmaterial such as hydrated magnesium silicate is condemned because ofvariation in water content on the one hand,657 and is recommended foradsorption chromatography, using elution by ethyl acetate satwrated withwater, on the other ; 658 or that “ single-phase chromatography ” of inorganicions,65g or even “ salting-out chromatography,” 660 may be regarded asadvances on partition chromatographic methods when they are in factprobably largely the result of separative forces recognised before the intro-duction of partition methods, such as ion exchange, or even simple adsorption.Finally, resolution of substances by complex liquid mixtures such asprogressively changing mixtures of chloroform, rt-amyl alcohol, and tert.-amylalcohol,661 while probably empirically satisfactory, can nevertheless onlymake theoretical interpretation of these separations more difficult.Inview of difficulties of this nature, it is only possible here to refer to isolatedinstances of methods which appear to be practically useful, and to payinadequate attention to theoretical considerations other than those whichmake a very simple approach to small sections of the larger problem.I tmust also be stressed that the allocation to separate types which is madehere must, of necessity, be somewhat arbitrary since the mechanisms are notalways evident.Adsorption Chromatography.-A number of less usual, sparingly soluble,inorganic compounds have been investigated in respect of their adsorptionproperties,662 and it has been found that when both natural and syntheticsources are available the natural product has a higher adsorptive capacity.A range of reagents for use in the detection of colourless zones in the separ-ation of a wide range of organic compounds has been tabulated, together withuseful information about their application.663 Various other methods,many of them instrumental, have been proposed for the detection of zones orfractions.664Inorganic chromatographic separations (as distinct from partitionseparations) have been discussed theoretically, 665 and have been appliedto the separation and identification of the more familiar cations 666 and654 E. L. Smith, Nature, 1952, 169, 60; T. C. J. Ovenston, ibid., p. 924; J. D. Acland,665 S. Burrows, F. S. M. Grylls, and J. S. Harrison, ibid., p. 800.656 A. Sibatani and M. Fukuda, J . Biochem. Tokyo, 1951, 38. 181.657 M. L. Wolfrom, A. Thompson, T. T. Galkowski, and E. J . Quinn, Aizalyt. Chem.,659 B. MiliCeviC, Bull. Soc. chim. Belgrade, 1952, 16, 101.660 L. Hagdahl and A.Tiselius, Nature, 1952, 170, 799.661 L. M. Marshall, K. 0. Donaldson, and F. Friedberg, Analyt. Chem., 1952,24,328,773.662 D. J . O’Connor and F. Bryant, Nature, 1952, 170, 84.6g3 A. L. LeRosen, R . T. Moravek, and J. K. Carlton, A n a l y t . Chem.. 1952, 24, 1335.664 P. H. Monaghan, P. B. Moseley, T. S. Burkhalter, and 0. A. Nance, ibid., p. 193;R . A. Glenn, J . S. Wolfarth, and C. W. DeWalt, ibid., p. 1138; J . M. Miller and J. G.Kirchner, ibid., p. 1480 : H. Hoyer, Kolloid Z . , 1952,’ 127, 166.665 M. Tanaka and M. Shibata, Bull. Tokyo Inst. Technol., 1951, B, 1, 11.G66 H. H. Fillinger and L. A. Trafton, J . Chem. Educ., 1952, 29, 255.ibid., 170, 32; H. G. Boman, ibid., p. 703.1952, 24, 1670. 6 5 8 C. H. Ice and S. H. Wender, ibid., p.1616336 ANALYTICAL CHEMISTRY.anions 667 and to the detection or determination of strontium,668 zinc incadmium,66g and copper in zinc.670 Further work has been carried out onthe separation of metal-chelates, the separation of 8-hydroxyquinolinecomplexes having been studied,671 and separation of cobalt by 2-nitroso-1-naphthol 672 and further investigations of the separation of alkaline-earth and alkali cations by violuric acid 673 having been reported.‘ I Gas chromatography ” of volatile organic mixtures, using displacementchromatography from charcoal columns, has been recommended 674 as avaluable method, capable of high accuracy and of considerable furtherdevelopment.Ion Exchange.-The principles and the application of ion exchange toanalytical problems have been extensively reviewed,675 and it is clear thatthese extend far beyond the simple possibilities of separations by columnaror analogous means.Chromatography of amino-acids has been carried outon oxidised cellulose, and study has shown 676 that the process taking placeis probably an ion-exchange process, the movement of individual acids beingrelated to the carboxyl content of the cellulose. Ion-exchange processeshave been used to remove or concentrate ions in water,677 to separateordinary 678 or radioactive 679 halogens, to separate calcium prior to phos-phate determination,6m to separate arsenic from iron,681 to remove inter-ferences prior to sulphate determination 682 or boron toseparate aluminium, iron , and manganese as chloro-complexes, 684 to separatethorium and lanthanum,685 to separate molybdenum from rhenium 686 orfrom other heavy metals,687 and to separate vanadium from phosphoricacid solutions.688An interesting development is the increasing application of ion-exchangecolumns for the production of standard solutions, and 0 .1 ~ - 689 and 0.001~-alkali hydroxide G90 free from carbonate have been prepared in this fashionfrom alkali chloride. The exchange is stoicheiometric, and the column willY. Oka and A. Murata, Sci. Rep. TGhoku, 1951, A , 3, 82.66E H. Ballczo and H. Muthenthaller, Mikrochem. Mikrochivn. A d a , 1952, 39, 152.669 Y. Oka and A. Murata, Sci. Rep. TGhoku, 1951, A , 3, 711.870 Idem, ibid., p. 707.671 L. B. Hilliard and H. Freiser, Analyt.Clzem., 1952, 24, 752.672 R. 0. Bach and A. A. Garmendia, Anal. Asoc. Quim. Argentina, 1951, 39, 11.*‘j H. Seiler, E. Sorkin, and H. Erlenmeyer, Helv. Chim. Acta, 1952, 35, 120.675 E. R. Tompkins, ibid., p. 970; R . Kunin, Analyt. Chem., 1952, 24, 64; Anon.,676 T. Wieland and A. Berg, ibid., 1952, 64, 418.877 H. Ballczo and G. Mondl, Mikyochem. Mikrochim. Acta, 1952, 39, 247 ; s. SUSSman878 W. Riemann and S. Lindenbaum, ibid., p. 1199.679 E. Berne, Acta Chem. Scand., 1951, 5, 1260.881 Y. Yoshino, Bull. Chem. SOC. Japan, 1951, 24, 39.68* H. Frey, AnaZyt. Chim. Acta, 1952, 6, 126.884 E. Blasius and M. Negwer, Naturwiss., 1952, 39, 257.8Eb P. Radhakrishna, Analyt. Chim. Acta, 1952, 6, 351.6E6 S. A. Fisher and V. W. Meloche, Analyt. Chem., 1952, 24, 1100.w7 R.Klement, 2. a n d . Chem., 1952, 136, 17.J. E. Salmon and H. R. Tietze, J., 1952, 2324.dm J . Steinbach and H. Freiser, Analyt. Chem., 1952, 24, 1027.6so B. W. Grunbaum, W. Schoniger, and P. L. Kirk, ibid., p. 1857.J. Griffiths, D. James, and C. Phillips, Analyst, 1952, 77, 897.Nature, 1952, 170, 150; G. Dickel and E;. Titzmann, Angew. Chem., 1951, 63, 450.and I. L. Portnoy, Analyl. Chem., 1952, 24, 1644.B. H. Kindt, E. W. Balis, and H. A. Liebhafsky, Analyt. Chem., 1952, 24, 1501.J. R. Martin and J . R. Hayes, Analyt. Chew., 1952, 24, 182; G. Brunisholtz andJ. Bonnet, Helv. Chim. A d a , 1951, 34, 2074WILSON PHYSICAL SEPARATION METHODS. 337deliver accurately standardised alkali without attention over a period ofmany months.C. Calmon 691 has proposed the use of the volume-changecharacteristics of an ion-exchange resin for quantitative analysis, either on alarge scale, where the volume occupied in a column is measured, or on a smallscale, where the change in volume of a single bead of resin is measured underthe microscope. The amount of swelling or shrinkage is related to thestructure of the resin, to the cation being exchanged, and to the concentrationof the exchanging solution.692In the organic field, separations of aldehydes and ketones from acids 693and of amino-acids 694 and nitrogenous plant extracts 695 have been reported.Extraction.-Solvent-extraction methods have been reviewed,696 and aradio-tracer study has been made of the solvent extraction of the halides ofgallium, indium, and thallium 697 from which it is possible to recommend anextraction of indium as iodide for separation from other elements.Leadiodide may be extracted by methyl isopropyl ketone,698 bismuth iodide byisobutyl methyl ketone,69g and copper by organic solutions containing organicacids.700 Apparatus for countercurrent e~traction,~Ol and a simple apparatusfor continuous extraction '02 have been described. In quantitative analysis,extraction procedures have been used in the removal of iron(Ir1) by extractionwith 12-butyl phosphate prior to aluminium determinati0r-1,~~~ in the estim-ation of zinc in soils by diphenylthiocarba~one,~~~ and in the extraction byethyl methyl ketone of niobium and tantalum from uranium alloys as thefluorides, prior to determination.705Partition Chromatrography.-As in recent years, the individual publica-tions on partition chromatography probably outnumber those in any othercomparable branch of analytical chemistry.Two books have been publishedwhich deal extensively with existing literature,'06 and the methods havebeen reviewed elsewhere. 707 Several investigations of factors affectingpartition separations have been reported, 708 the most fundamental probablybeing those of H. G. C a s ~ i d y , ~ ~ ~ who has analysed the factors into threemain groups, not, of course, mutually exclusive, affecting flow, R p values,691 Analyt. Chem., 1952, 24, 1456.692 K. W. Pepper, D. Reichenberg, and D. K. Hale, J . , 1952, 3129.693 G.Gabrielson and 0. Samuelson, Acta Chem. Scand., 1952, 6, 729, 738.694 C. H. W. Hirs, S. Moore, and W. H. Stein, J . Biol. Chem., 1952, 195, 669.695 S. M. Partridge, Analyst, 1952, 77, 955.696 L. C . Craig, Analyt. Chem., 1952, 24, 66; D. Pillon, Bull. SOC. chim., 1952, 1 9 , ~ 1.697 H. M. Irving and F. J. C. Rossotti, Analyst, 1952, 77, 801.698 P. W. West and J. K. Carlton, Analyt. Chim. Acta, 1952, 6, 406.69g P. W. West, P. Senise, and J. K. Carlton, ibid., p. 488.700 P. W. West, T. G. Lyons, and J. K. Carlton, ibid., p. 400.701 F. C. Hickey, Analyt. Chern., 1952, 24, 1993; R. Spence and R. J . W. Streeton,'02 W. W. Meinke and R. E. Anderson, Analyt. Chem., 1952, 24, 708.703 M. Aven and H. Freiser, Analyt. Chim. A d a , 1952, 8, 412.$04 E.Shaw and L. A. Dean, Soil Sci., 1952, 73, 341.705 G. W. C. Milner and A. J. Wood, Atomic Energy Res. Establ., 1952, C/R 895.706 R. J. Block, R. LeStrange, and G. Zweig, " Paper Chromatography : A Labora-tory Manual," New York and London, 1952 : J. N. Balston and B. E. Talbot, " Guide toFilter Paper and Cellulose Powder Chromatography," London, 1952.707 P. von Tavel, Chimia, 1951, 5, 256; R. Signer, ibid., p. 245.' 0 8 G. N. Kowkabany and H. G. Cassidy, Analyt. Chem., 1952, 24, 643 ; A. Lacourt,G. Sommereyns, and G. Wantier, Analyst, 1953, 77, 943; C. N. Trumbore and H. E.Rogers, J . Chem. Educ., 1952, 29, 404; G. Heinrich, Naturwiss., 1952, 39, 257.709 Analyt. Chem., 1952, 24, 1415.Analyst, 1952, 77, 578338 ANALYTICAL CHEMISTRY.and zone-definition respectively, and has considered some of these factorsin more detail.Instrumental methods have been recommended for con-trolling separations, 710 and numerous devices of apparatus, application ofreagent, choice of support for the stationary phase, and detection of zoneshave been reported.711 I t has been shown that the measurement of spotareas 712 or the excision of spots and elution for quantitative analysis 713 maybe considerably simplified either by direct analysis on the cut paper 714 or bycutting out the spots and weighing d i r e ~ t l y . 7 ~ ~ In the latter case the result ismore closely related to the concentration than the actual spot area, probablybecause of compensation for errors arising from varying paper thickness.In the organic field alcohols,716 the 2 : 4-dinitrophenylhydrazones ofaldehydes and ketonesJ717 a m i n e ~ , ~ ~ ~ azo-dyes derived froma ~ y l a m i n e s , ~ ~ ~ phenols,721 sugars and related compounds 7 2 2 9 723 and amino-acids and related compounds 7237 724 are among the long list of substancesthat have been separated.Because of the considerable use of benzidine in the detection of zones,its behaviour with a wide range of materials, including inorganic salts, hasbeen The halides from halogen compounds, after sodium fusion,have been separated.726 Separations of a number of mixtures of inorganic710 D.C. Miiller, AnaZyst, 1952, 77, 933.711 P. Meredith and H. G. Sammons, ibid., p. 416; L. A. Boggs, Analyt. Chem., 1952,24, 1673; L. A. Boggs, L.S. Cuendet, M. Dubois, and F. Smith, ibid., p. 1148; D. F.Meigh, Nature, 1952, 169, 706; U. S. von Euler, ibid., 170, 664; A. Grieg, ibid., p. 845;G. Zimmermann and K. Nehring, Angew. Chenz., 1951, 63, 556; J . G. Marchal and T.Mittwer, Proc. K. Ned. Akad. Wet., 1951, 54, c 4, 391; S. Berlingozzi and G. Serchi,Sper. Sez. Chim. biol., 1952, 3, 1.?la J. A. Brown and M. M. Marsh, Analyt. Chem., 1952, 24, 1952.714 B. Levin and V. G. Oberholzer, ibid., p. 123.716 J. H. Freeman, Analyt. Chem., 1952, 24, 2001.716 A. C. Neish, Canad. J , Chem., 1951, 29, 552.717 D. F. Meigh, Nature, 1952, 170, 579.718 F. W. Denison and E. F. Phares, Analyt. Chem., 1952, 24, 1628; T. L. Parkinson,Analyst, 1952, 77, 438; V. K. M. Rao, J . Sci. I n d . Res., India, 1952, 11, B, 277; S.S.Phatak, A. P. Mahadevan, and V. D. Patwardhan, Current Sci., 1952, 21, 162.W. Baker, J. B. Harborne, and W. D. Ollis, J., 1952, 3215; J. M. Bremner andR. H. Kenten, Biochem. J . , 1951, 49, 651; A. Wickstrom and B. Salvesen, J . Pharm.Pharmacol., 1952, 4, 631; R. Schwyzer, Acta Chem. Scand., 1952, 6, 219.M. Zalokar, J . Amer. Chem. Soc., 1952, 74, 4213.721 Wen-Hua Chang, R. L. Hossfeld, and W. M. Sandstrom, ibid., p. 5766; G. M.Barton, R. S. Evans, and J. A. F. Gardner, NatuYe, 1952, 170, 249; S. A. Ashmore andH. Savage, Analyst, 1952, 77, 439.TZ2 J . L. Buchan and R. I. Savage, ibid., p. 401 ; N. Albon and D. Gross, ibid., p. 410;J. T. Edward and D. M. Waldron, J . , 1952, 3631; R. J. Dimler, W. C. Schaeffer, C. S.Wise, and C.E. Rist, Analyt. Chem., 1952, 24, 1411; L. Sattler, ibid., p. 1862; R. J .Bayley, E. J . Bourne, and M. Stacey, Nature, 1952, 169, 876; P. S. Rao and R. M.Beri, Proc. Indian Acad. Sci., 1951, 28, A , 368; A. Yoda, Sugar I n d . Abstr., 1952, 14,116; J. Saarnio, E. Niskasaari, and C . Gustafsson, Suomen Kem., 1952, 25, B, 25;J. Opienska-Blauth, E. Drozdowski, and M. Kanski, Ann. Univ. M . Curie-Sklowdowska,1951, 6, D, 27.723 L. F. Wiggins and J. H. Williams, Nature, 1952, 170, 279; R. Radhakrishna-murty and P. S. Sarma, J . Sci. I n d . Res., India, 1952, 11, B, 279.724 C. Klatzkin, Nature, 1952, 169, 422; H. N. Rydon and. P. W. G. Smith, ibid.p. 922; K. V. Giri and N. A. N. Rao, ibid., p. 923; A. C. Hulme and W. Arthjngton.ibid., 170, 659; A.R. Kemble and H. T. Macpherson, ibid., p. 664: K. V. Giri, A. N.Radhakrishnan, and S. V. Vaidyanathan, Analyt. Chem., 1952, 24, 1677 ; E. F. Welling-ton, Canad. J . Chem., 1952, 30, 581.725 H. Miller and D. M. Kraemer, Analyt. Chem., 1952, 24, 1371.7 2 6 T. Ando and S. Ishii, Bull. Chenz. SOC. Japan, 1952, 25, 106.T. Kariyone and S. Shimizu, Nature, 1952, 170, 422WILSON : MISCELLANEOUS. 339ions have been reported.727 More limited separations have been describedfor phosphates, 728 alkali metals, 729, 730 alkaline-earth metals, 730 zinc, 731uranium,733, 734 735 niobium and tantalum,736 andzirconium and hafnium. 737On theoretical considerations, partition methods have been extendedto partition between gas-liquid phases, and some separations based on thistheory, such as the separation of volatile fatty acids, are described.738Ionophoresis and Electrophoresis.-The methods of “ electrochromato-graphy ” have been re~iewed,~3~ and apparatus for carrying out ionophoreticor electrophoretic separations in filter-paper has been described.740 G.Manecke 741 has described the application of ionophoretic separations tomixtures of ions on ion-exchange columns. Copper has been separated anddetermined on paper by ionophoretic methods. 742 The methods normallyapplied in this field have utilised low voltages to achieve separations.Flavonoids and sugars have been separated by using high constant voltagesof the order of 100-1000 volts.7439. MISCELLANEOUS.Radiochemical Analysis.-An excellent account of the basis and ex-perimental aspects of radiochemical analysis has appeared in book form, 744and there have been other reviews of the subject 745 from the analyticalstandpoint. The precision counting of a-particles has been discussed 746 anda method of apportioning radioactivity between radioactive parents andJ .G. Surak and D. P. Schlueter, J . Chem. Educ., 1952, 29, 144; H. H. Fillingerand L. A. Trafton, ibid., p. 285; F. H. Pollard and J. I;. W. McOmie, Endeavour, 1951, 10,213; G. Venture110 and A. M. Ghe, Analyt. Claim. Acta, 1952, 7, 261, 268; A. Lacourt,G. Sommereyns, and J. Soete, Mikrochenz. Mikrochim. Acta, 1951, 38, 348; A. Lacourt,G. Sommereyns, and M. Claret, ibid., p. 444; A. Lacourt, G. Sommereyns, and G.Wantier, ibid., 1952, 39, 396; A.Lacourt, G. Sommereyns, J. Hoffmann, A. Stadler, andG. Wantier, Compt. rend., 1952, 234, 2365.728 J . P. Ebel and Y . Volmar, ibid., 1951, 233, 415; T. Ando, J. Ito, S. Ishi, and T.Soda, Bull. Chem. SOC. Japan, 1952, 25, 78.729 D. P. Burma, Analyst, 1952, 77, 382.730 H. Erlenmeyer, H. von Hahn, and E. Sorkin, He2v. Chim. A d a , 1951, 34, 1419.731 W. Hermanowicz and C. Sikorowska, Pam. Chem., 1952, 8, 238.732 M. M. Singh and J. Gupta, J . Sci. I n d . Res., India, 1951, 10, B, 289.733 W. Ryan and A. F. Williams, Analyst, 1952, 77, 293.734 A. F. Williams, ibid., p. 297.735 N. F. Kember, ibid., p. 78; G. W. J. Kingsbury and R. B. F. Temple, ibid., p. 307.736 F. H. Burstall and A. F. Williams, ibid., p. 983; F . H. Burstall, P.Swain, A. F.Williams, and G. A. Wood, J . , 1952, 1497; A. F. Williams, ibid., p. 3155; R. A. Mercerand A. F. Williams, ibid., p. 3399.737 N. F. Kember and R. A. Wells, Chem. and Ind., 1952, 1129.738 A. T. James and A. J. P. Martin, Biochem. J . , 1952, 50,679; Analyst, 1952, 77,915.73B H. H. Strain, Analyt. Chem., 1952, 24, 356; M. Lederer and F. L. Ward, Analyt.Chim. Acta, 1952, 0, 355.740 T. R. Sato, W. P. Norris, and H. H. Strain, Analyt. Chem., 1952, 24, 776; A.Tiselius, J . Gen. Physiol., 1951, 35, 89; R. Consden and W. M. Stanier, N a t w e , 1952,169, 783; 170, 1069; A. B. Foster, Chem. and Ind., 1952, 1050; I . Brattsten and A.Nilsson, Arkiv Kemi, 1951, 3, 337.741 G. Manecke, Naturaiss., 1952, 39, 62.742 J . R. A. Anderson and M.Lederer, Analyt. Chim. A d a , 1952, 6, 472.743 Y . Hashimoto, I. Mori, and M. Kimura, Nature, 1952, 170, 975.744 G. B. Cook and J. F. Duncan, “ Modern Radiochemical Practice,” Oxford, 1952.745 J. E. Hudgens, Analyt. Chem., 1952, 24, 1704; M. P. Sue, Bull. SOC. chim., 1951,746 R. Hurst and G. R. Hall, Analyst, 1952, 77, 790.18, D 9340 ANALYTICAL CHEMISTRY.daughters has been described. 747 Radio-tracers have been used for chrom-atographic separations. 748 Some reactions of thiosulphate and tetrathionatehave been studied 'by tracer methods. 749 Precautions necessary for re-producible results in the elementary analysis of organic compounds con-taining radio-tracers have been described. 750 Radioactivity measurementshave been employed for the determination of potassium, 7513 752 rubidium,752chromium, vanadium, and molybdenum, 753 astatine,7" francium, 755 andamericium. 756 Radioactive iron has been separated from biological materialsby precipitation with cupferron and subsequent extraction.757Radioactivation.-This important new technique for the determination,particularly, of microgram or sub-microgram amounts of materials, has beenconsiderably extended in its application. Conditions have been describedfor the determination of copper in luminescent solids,758 uranium in rocksand minerals, 759 indium, 760 arsenic, 761 antimony,762 and trace elements inhigh-purity aluminium 763 and in high-purity magnesium.764Non-radioactive Tracers.-Methods for the determination of deuteriumhave been discussed.765 Methods have been described for the isolationof hydrogen before isotopic assay,766 and for the dekermination of oxygenin organic compounds 767 and of hydrate-water.768 Combined chemicalanalysis and tracer assay in organic analysis has been discussed, and rapidand accurate methods making use of simple interlocked chemical andtracer procedures have been described. 769Gas Analysis.-The use of a simple apparatus for the detection of a widerange of gases has been described,770 and sensitivities for the reactions arequoted. A simple manometric gas-analysis apparatus for general quan-titative and the analysis of gas mixtures containing oxides of nitro-gen 772 have been described. A method of analysis depending on desorptionF. P.W. Win-teringham, A. Harrison, and R. G. Bridges, Analyst, 1952, 77, 19; E. L. Smith and D.Allison, ibid., p. 29.747 H. W. Kirby, Analyt. Chem., 1952, 24, 1678.748 0. G. Lion, E. A. Peterson, and D. M. Greenberg, ibid., p. 920,74s H. R. v. d . Heijde and A. H. W. Aten, J . Amer. Chem. Soc., 1952, 74, 3706.750 E. A. Evans and J . L. Huston, Analyt. Chem., 1952, 24, 1482.751 0. Gubeli and K. Stammbach, Helv. Chim. Acta, 1951, 34, 1245.7 5 2 Idern, ibid., p. 1253.753 J . Govaerts and C. Barcia Goyanes, Analyt. Chim. Acta, 1952, 6, 121.754 A. H. W. Aten, T. Doorgeest, U. Hollstein, and H. P. Moeken, AwaZysl, 1952,7 5 5 E . K. Hyde, J . Amer. Chem. Soc., 1952, 74, 4181.75~1 H. W. Miller, Nuclear Sci. Abstr., 1952, 6, 15.7 5 7 R. E. Peterson, Analyt.Chem., 1952, 24, 1850.7 5 * E. Grillot, Compt. rend., 1952, 234, 1775.75s A. A. Smales, Anal-yst, 1952, 77, 778.760 J . E. Hudgens and L. C. Nelson, Analyt. Chem., 1952, 24, 1472.7 6 1 A. A. Smales and B. D. Pate, ibid., p. 717; Analyst, 1952, 77, 188, 196.762 J. E. Hudgens and P. J. Call, AnaZyt. Cheln., 1952, 24, 171.763 P. Albert, M. Caron, and G. Chaudron, Compt. rend., 1951, 233, 1108.7 ~ 3 ~ G. J. Atchison and.W. H. Beamer, Analyt. Chem., 1952, 24, 1812.765 M. E. Reinders, Chem. Weekblad, 1951, 47, 785.7 6 6 1. Figeleisen, M. L. Perlman, and H. C. Prosser, Analyt. Chem., 1952, 24, 1356.7 G 7 A. V. Grosse and A. D. Kirshenbaum, ibid., p. 584; A. D. Kirshenbaum, A. G.768 H. J. Morowitz and H. P. Broida, ibid., p. 1657.769 R. C. Anderson, Y . Delabarre, and A. A. Bothner-by, ibid., p. 1298.770 H. Malissa, A. Musil, and R. Kreibich, Mikrochem. Mikrochim. Acta, 1951, 38,7 7 1 J. N. Pitts, D. D. DeFord, and G. W. Recktenwald, Analyt. Chem., 1952, 24, 1566.772 C. L. Johnson, zbid., p. 1572 ; G. Meyer and P. Vooge1,Rec. Trav. chim., 1951,70,833.77, 774.Streng, and A. V. Grosse, ibid., p. 1361.385, 403WILSON MISCELLANEOUS. 341followed by heat-conductivity measurements has been proposed. 773 Indirectanalysis of mixtures by the measurement of the gas evolved by a suitablereaction has been re~omrnended.7~~ Ethylenediamine is stated to be areadily purified absorbent for carbon dioxide, 775 possessing the advantagethat it is easily separated from its carbonate by vacuum distillation.Moisture Determination.-A micro-method for the deJermination ofhydrate-water in minerals has been described.776 The preparation and useof the Karl Fischer reagent has been discussed in and its use in thepresence of ferric salts 778 and with a dead-stop end-point apparatus 779 hasbeen described. A solution of bromine and sulphur dioxide in chloroformhas been recommended 780 as being more satisfactory in some determinationsthan the Karl Fischer reagent. Water in alcohols has been determined byusing high-frequency oscillators, 781 and this method is reported to giveparticularly good results in the system ethanol-water.Operations in Non-aqueous Solvents.-Acid-base 782 and general 783titrations in non-aqueous solvents have been reviewed. Apart from in-vestigations noted elsewhere in this Report, the titration of ammonium andamine salts of mineral and of a range of sodium and other metalsalts 785 and of amines 786 has been described. The electrochemical potentialsof a number of inorganic and organic redox systems in pyridine have beendetermined.787 It has been shown that by using a glass electrode acid-basetitrations in this solvent might also be possible. Ionophoretic separation ofdye mixtures in non-aqueous solvents has been achieved. 788Sedimentation Analysis.-Lead has been determined by centrifuging leadsulphate, 789 and the zinc-1 : 10-phenanthroline reaction already mentioned 73has been used in a sedimentation determination of vanadium.Catalysed Reactions-Both qualitative and quantitative methodsbased on catalysed reactions, in addition to those mentioned elsewhere inthis Report, have been proposed. Cobalt may be detected by a catalysedoxidation of manganese(I1) to manganese(~v).~~ The reducing power of themercurous ion is enhanced in the presence of thiocyanate, so that it can bedetected by its ability to reduce iron(II1) to iron(I1) (cf. p. 316).791 Coppermay be used for the catalytic reduction of nitrate to ammonia for quantitativedetermination. 792 Various catalysts have been employed in the iodometric773 H. Wirth, Mikrochem. Mikvochinz. A d a , 1952, 40, 15.774 N. I . Pyshkin and 0. M. Lukin, J . Anal. Chem., U.S.S.R., 1951, 6, 261.7 7 5 R. W. Swick, D. L. Buchanan, and A. Nakao, Analyt. Cheun., 1952, 24, 2000.776 E. B. Sandell, Mikrochern. Milirochim. Acta, 1951, 38, 48’7.777 E. Eberius, 2. anal. Chem., 1952, 137, 81.778 A. H. Laurene, Analyt. Chem., 1952, 24, 1496.779 W. A. Frediniani, ibzd., p. 1126.781 P. W. West, P. Senise, and T. S. Burkhalter, Analyt. Chem., 1952, 24, 1250.782 J. A. Riddick, ibid., p. 41.783 J . A. Riddick, J . S. Fritz, M. M. Davis, E. F. Hillenbrand, and P. C. Markunas,ibid., p. 310; T. S. West, I n d . Chem. Chern. Manuf., 1952, 28, 368, 415.784 J. S. Fritz, A m l y t . Chem., 1952, 24, 306.785 C. W. Pifer and E. G. Wollish, ibid., p. 519.786 R. J. Keen and J . S. Fritz, zbzd., p. 564.787 A. K. Gupta, J . , 1952, 3473, 3479.788 M. H. Paul and E. L. Durrum, J . Amer. Chern. SOC., 1952, 74, 4721.789 R. C. Jarnagin, J. T. Jones, 0. L. Willbanks, and C. T. Kenner, Analyt. Chem.,7y0 P. W. West and L. A. Longacre, Analyt. Clzina. Acta, 1952, 6, 485.;91 F. Lucena Conde, Mikvochem. Mzkrochzrn. A d a , 1952, 40, 8.7Q2 2. G. Szab6 and L. G. Bartha, Analyt. Chim. Acta, 1952, 6, 416.T. S. West, I n d . Chem. Chem. Manuf., 1952, 28, 491.1952, 24, 1115342 ANALYTICAL CHEMISTRY.determination of persulphate. 793 Copper in sub-microgram amounts maybe determined by its catalytic effect on resorcinol 0xidation,~~4 silver by asimilar effect on the persulphate oxidation of manganese(II),795 and iron by itscatalytic effect, when co-precipitated with a cobalt-copper hydroxide carrier,on the decomposition of hydrogen per0xide.7~6 The reduction of palladiumin the presence of selenium by hydrazine sulphate has been utilised for thedetermination of palladium. 797Miscellaneous Methods.-There are several methods which cannotproperly be classified under any heading, but which seem to present distinctpossibilities to the analyst. H. M. Powell 798 has shown that clathrate-formation may be used in the resolution of optical isomers, and a somewhatsimilar operation, the formation of urea and thiourea adducts, 799 has alsobeen found to encourage separation. The use of specific adsorbents, firstsuggested by L. Pau1ing,8O0 has been investigated, and some success has beenachieved with these.gOl There is some indication of a relation between thestructure of the substance adsorbed and specificity, but the results are notnearly extensive enough to allow any precise deductions to be made regardingthis. Finally, D. J. D. Nicholas has shown so2 that by altering the amount oftrace metal in a nutrient on which a fungus is growing, the amount of themetal may be assessed by growth of the fungus, over a range from zerocontent to sufficiency level.CECIL L. V71~soh’.793 Z. G. Szab6, L. Csanyi, and H. Galiba, 2. anal. Chem., 1952, 135, 269.794 R. H. Lambert, Analyt. Chem., 1952, 24,. 868.795 A. L. Underwood, A. M. Burrill, and L. B. Rogers, ibid., p. 1697.796 A. Krause, Roczn. Chem., 1952, 26, 3.797 F. Pino Perez and F. Burriel Marti, Anal. real SOC. esp. Fis. Quim., 1951, 47, B,798 Nature, 1952, 170, 155.790 W. Schlenk, Analyst, 1952, 77, 867.Chem. Eng. News, 1949, 27, 913.F. H. Dickey, Proc. N u t . Acad. Sci., 1949, 35, 229; U. Curti and U. Colombo,J . Amer. Chem. Soc., 1952, 74, 3961; S. A. Bernhard, ibid., p. 4046.Analyst, 1952, 77, 629.653, 657