ANALYTICAL CHEMISTRY.1. INTRODUCTION.THERE have been at least two attempts recently to distinguish betweeninorganic and organic analysis, in the special context of organic qualitativeanalysis, by defining inorganic methods as those used largely for the identi-fication of elements or ions, organic tests being more concerned with theidentification of functional groups or even of compounds as a whole. It istrue that in the past this broad distinction has been generally accepted. Itis equally true that there have been notable exceptions, where the inorganicanalyst has not been content to identify only the elements or ions present,since this is no answer to his problem. A classical instance of this, whichis still receiving attention,2 is the analysis of complex mixtures of phosphates.In such a problem the percentage of phosphorus present gives little guidanceon the nature of the mixture.Each of the phosphates must be characterisedand determined separately.There are indications that the inorganic analyst, faced with multiplyinginvestigations on the covalent compounds of the non-metals, will have topay more attention to compound analysis. In the analysis of a simplemixture of, say, chlorine trifluoride and fl~orine,~ the elementary compositionwill probably be sufficient if one is certain that no other constituents arepresent. It only needs the mixture to be complicated by the addition ofa third constituent to require an investigation of a completely different order.Such mixtures, through the rapidly expanding chemistry of fluorine, mustbe met with much more frequently in the future.Again, in the strivingafter high purity which new industrial demands have emphasised in the pastfew years, it is often the form of the impurity rather than its elementalcharacter which is of importance-the precise oxide or oxides, let us say, andthe relative proportions of them that are present, rather than the fact thatoxygen is the contaminant. This is vital information which the analyst isexpected to supply.All of this indicates that the analyst who in the past has regarded himselfas being chiefly concerned with inorganic materials, and who does notenvisage any change in this situation in the future, may very well requireto approach his problems from a different point of view.He may find itnot only advantageous, but even necessary, to familiarise himself with theapproach of the organic analyst to his problems. As a consequence, it islikely that physical methods may prove to have an even more importantpart to play in some sections of inorganic analysis than in the past ; it is sooften only through instruments that the organic chemist is able to get aproper analysis, in the molecular sense, of the complex mixtures of relatedcompounds which confront him.It may be retorted that the wise inorganic analyst has, in the past, made1 F. Feigl, Mikvochem. A d a , 1953, 157 ; R. Palland, Ann. Chim. analyt., 1952, 34, 194.a W. Dewald and H. Schmidt, 2. anal. Chem., 1952-1953, 137, 178; 1953, 138, 91 ;139, 359; H.Etienne, Ind. Chim. belg., 1953, 2, 340.3 S. Katz and J . T. Barr, Analyt. Chem., 1953, 25, 619WILSON : INTRODUCTION. 337extensive use of instrumental analysis; the Reports for the past few yearscertainly appear to bear this out, since a glance a t them shows the extent towhich the instrument has penetrated into the general analytical laboratory.Closer examination of the situation reveals, however, that on the inorganicside the bulk of instrumental work has still been directed towards elementor ion analysis. Other applications have tended to be regarded as specialproblems. The Reporter would venture to predict that the signs of achange in this attitude, spasmodic during the past few years, will becomemore frequent; that routine molecular analysis is a problem that will cometo affect much more acutely all analysts concerned with inorganic material;and that as a consequence, the division generally held to separate inorganicand organic analysis will become considerably less sharply defined within ashort period of time.During the past year developments have been mainly along lines whichcould, on the whole, have been fairly expected. That is to say, there islittle that one could call inspired advance, and work has largely been basedon previous discoveries.Perhaps this contention requires some elaboration.Although much of the work is important, the development of a new reagentfor a particular cation, or the use of an old reagent in a new way, is notnecessarily to be included in the category here referred to as “ inspired ”work.Such work usually involves the application of a completely newprinciple, and sometimes the jettisoning of a mass of preconceived ideas builton a generation of existing research. As a minor example of what is meant,one paper may be picked out without any suggestion that it is a betterexample than others dealt with here and there throughout this Report.Much work has gone into devising a satisfactory medium for the decom-position of organic nitrogenous material before Kjeldahl determination ofthe nitrogen in the form of ammonia. Sulphuric acid, with varying additionalsubstances whose function is not always clear, is normally used. S. M.Woods, D. Scheirer, and E. C. Wagner,4 starting from first principles, pointout that strong reduction, rather than the usual oxidation, is the logicalmeans of achieving the degradation, and have carried out some preliminarywork on a method which, whatever its experimental merits may ultimatelyprove to be, at least has the veritable advantage of an unusual approach.While on this subject of new methods, the Reporter would comment onthe unnecessary frequency with which methods are advertised in the liter-ature as ‘‘ new methods ” for various purposes.This seems an undesirableemphasis, doubly so when, as often happens, the reader finds that the methodis a revival of a method current thirty or forty years ago, or is merely anadaptation of a method established by another worker.The complaint voiced in last year’s Report regarding the naming ofreagents can be reiterated.The lot of the analytical chemist is made noeasier when he encounters as a reagent “ 2-(2-hydroxy-3 : 6-disulpho-l-napht hy1azo)-benzenearsonic acid (Thorin) , also known as 1- (2-arsono-benzeneazo)-Z-naphthol-3 : 6-disulphonic acid, and under the synonymsThoron and Naphtharson.” Some sort of comprehensive register of thenames, trade names, and abbreviated names of reagents is urgently required.The form of this year’s Report follows in general those of the past twoAnalyt. Chem., 1953, 25, 837.D. W. Margerum, C . H. Byrd, S. A. Reed, and C . V. Banks, ibid., p. 1219338 ANALYTICAL CHEMISTRY.years. Where possible, as for example in the order with which the inorganicelements are considered, the Reporter has tried to utilise the UniversalDecimal Classification.This classification, however, pa.rticularly in thesection dealing with analytical chemistry, is quite inadequate to deal withthe range of topics falling within the scope of the Report, so that departuresfrom the strict arrangement are numerous and inevitable.2. GENERAL.Several useful textbooks have appeared dealing primarily with industrialinorganic analysis.’ The modern approach required by the analyst is dealtwith in general terms by D. W. Kent- Jones,s and the training of analysts,both as it has been in the past and as it ought to develop in the future, hasbeen discussed by J . H a ~ l a m . ~ The present position, and likely develop-inents in the future, have been outlined for microchemistry lo and for clinicalanalysis.ll Methods at present used and likely to prove of use in analysingmicrogram and submicrogram amounts of material, particularly in dilutesolution, have been described.lZ The apparatus and techniques which canbe used for ordinary inorganic analysis on the microgram scale have beendescribed in detail.13E.C. Yehle l4 has investigated the effects of laboratory variation inassessing from analytical results the true variation from one batch of materialto another, and has pointed out that occasionally the method of analysismay be a significantly more important source of apparent variation than thevariables actually arising in production. The indirect analysis of three-component systems such as mixtures of the chloride, bromide, and iodide ofpotassium, by the determination of three equivalents, has been discussedby H.Bode.15 It is shown that the three equivalents must be obtainedfrom truly independent determinations, and that it will always be difficult,in any such system, to find three independent equivalents that can be deter-mined with sufficient accuracy to be useful for analytical purposes. Amathematical simplification of the simultaneous equation method of deter-mining multi-component systems, applicable when only one component isrequired, has been proposed as a solution in selected cases.16An electrically heated oven l 7 and a heating block which can be fittedfor a wide variety of microanalytical apparatus,18 both of which can be usedwith automatic temperature control, have been described.A collectedaccount of a wide variety of small items of apparatus including stirring andallied devices, apparatus for inorganic and organic analysis, for electro-Brit. Std. Specif. 1000 : Vol. 2, Pt. 2, 1943.W. F. Hillebrand, G. E. F. Lundell, H. A. Bright, and J. I.,,Hoffmann, “AppliedInorganic Analysis,” 2nd Ed., New York, 1953 ; R. S. Young, Industrial InorganicAnalysis,” London, 1953 ; F, Specht, “ Quantitative anorganische Analyse in derTechnik,” Weinheim, 1953. /. Roy. Inst. Chem., 1953, 77, 479.Ibid., p. 482. 10 C. L. Wilson, Mikrochim. Acta, 1953, 58.l2 L. B. Rogers, J . Chem. Educ., 1952, 29, 612.1 4 Analyt. Chem., 1953, 25, 1047.l1 R. M. Archibald, Analyt.Chem., 1953, 25, 2; G. Glick, Chem. Eng. News, 1953,l3 H. M. El-Badry and C. L. Wilson, Mikrochem. Mikrochim. Acta, 1952-1953, 40,l5 2. anal. Chem., 1953, 139, 101.l6 E. Allen and W. Rieman, Analyt. Chem., 1953, 25, 1325.** Idem, ibid., p. 245.31, 139.141.R. T. E. Schenclr and T. S. Ma, Mikrochem. Mikrochim. Acta, 1952-53, 40, 236WILSON GENERAL. 339chemical techniques, and for titration, has appeared.lg The problem ofcleaning glass apparatus, in particular as applied to apparatus contaminatedwith silicone greases, has been discussed by several workers.20Methods have been proposed for a systematic semimicro-analysis ofsilicates,2l and for the determination of various components of complexphosphate mixtures.2 Reviews of recent progress in ferrous22 and non-ferrous 23 metallurgy have been published.The microanalysis of the alkali-met a1 group has been comprehensively e~amined.2~ Reviews of the analyticalchemistry of germanium,25 beryllium,26 aluminium,27 the lanthanons,28thallium,29 uranium,zO and the platinum-group metals 31, 32 have appeared.A critical review has been made 33 of the methods in use for the destructionof organic matter before the determination of trace metals, and the variouscriticisms of such methods are fully discussed. Methods have been describedfor the determination of impurities in germanium and silicon,34 in titaniumand in titanium alloys.36 Analytical applications of liquid amalgamshave been re~iewed.~’Reagents.-G. F. Smith 38 has described a completely safe method for thepreparation of anhydrous perchloric acid from 72% perchloric acid and 20%fuming sulphuric acid.A new edition of a standard work on organic reagentsfor metals has been p~blished.3~ Tetraphenylphosphonium chloride and thecorresponding antimony compound have been proposed 40 as analyticalreagents which produce insoluble compounds with a wide range of simpleand complex anions, thus providing either gravimetric or titrimetric methodsof determination. All the complexes are extractable from aqueous solutionby chloroform. 2. G. Szab6 and M. T. Beck41 have, from theoretical con-siderations, proposed various practical applications of the complexes formedby aluminium with fluoride ions. They have also discussed the behaviourof phosphoric, tartaric, citric, and other acids as complexing agents.Structural determinations by means of X-rays of various compounds ofinterest in analytical chemistry, and in particular of dimethylglyoxime andits nickel complex, of the zinc 8-hydroxyquinoline complex, and of nickellg J.T. Stock and M. A. Fill, Mikrochim. Ada, 1953, 89; I n d . Chem. Chem. Manuf.,2o A. W. Armstrong, Chem. and Ind., 1953, 219; D. M. C. ReilIy, ibid., p. 411;21 R. B. Corey and M. L. Jackson, Analyt. Chem., 1953, 25, 624.22 H. F. Beeghly, ibid., p. 30.24 C. Duval, Ann. Chim. analyt., 1952, 34, 209.25 H. H. Krause and 0. H. Johnson, Analyt. Chem., 1053, 25, 134.26 F. A. Vinci, ibid., p. 1580.27 ill. Kapel, I n d . Chem. Chem. M a n u f , , 1953, 29:,539, 573.28 R.C. Vickery, ‘ I Chemistry of the Lanthanons, London, 1953 ; I n d . Chem. Chem.ag J. R. A. Anderson, Analyt. Chem., 1953, 25, 108.30 C. J. Rodden, ibid., p. 1598.31 W. M. MacNevin, ibid., p. 1612; F. E. Beamish and W. A. E. MacBryde, ibid.,32 R. Gilchrist, ibid.. p. 1617.33 G. Middleton and R. E. Stuckey, Analyst, 1953, 78, 532.34 C. L. Luke and M. E. Campbell, Analyt. Chem., 1953, 25, 1588.36 J. M. Thompson, ibid., p. 1231.3G hl. Codell, C. Clemency, and G. Norwitz, ibid., p. 1432.3 7 W. I. Stephen, I n d . Chem. Chem. Manuf., 1953, 29, 31, 79, 128, 169.38 J . Amer. Chem. SOC., 1953, 75, 184.39 W. Prodlinger, “ Organische Fallungsmittel in der Quantitativen Analyse,” 3rdQ0 €3. 1-1. Willard and L. R. Perkins, ,4naZyt. Chem., 1953, 25, 1634.41 Ibid., p. 103.1953, 29, 56.H. K. Black and R. A. Gill, ibid., p. 519; R. H. A. Crawley, ibid., p. 1205.z3 M. L. Moss, ibid., p. 37.Manuf., 1953, 29, 260, 291.p. 1613.Ed., Stuttgart, 1953340 ANALYTICAL CHEMISTRY.salicylaldoxime, have been described.42 R. J. P. Williams 43 has discussedthe theoretical principles which may be used in choosing the types of reagentlikely to possess selective action towards a metal cation, and on the basis ofthis has made some suggestions for the design of further reagents. Theinformation which may be obtained from magnetic measurements regardingthe structures of complexes has been considered by R. S. Nyholm.44 H.Irving and R. J. P. Williams 45 report that from critical examination of thestabilities of complexes formed by the bivalent cations of the first transitionseries of metals, the order of stability Mn < Fe < Co < Ni < Cu < Znappears to hold fairly generally. Methods for determining stability con-stants have been discussed46 and an attempt has been made to assess theorigin of increase of stability of complexes due to chelate ring formation.47It has been shown that in ethanol, in the absence of water, certain chelatingreactions occur more readily than if water is present.48 The complexes ofp-diketones have been extensively examined.49 Complexes with otherorganic reagents which have a bearing on analytical chemistry and whichhave been examined in some detail include those formed with 2-substituted1 : lO-phenanthrolines,50 4-pyridine-2’-azo-NN-dimethylaiziline, 51 and NN-bis-2-hydro~yethylglycine.~~ Acetylacetone may act both as solvent and ascomplexing agent, and this property, which has been utilised in separationsof copper from zinc, is likely to have more extensive application^.^^ Thestructure of the complex of this reagent with cobalt has been examined.54As in the last few years, more work has been published on ethylene-diaminetetra-acetic acid than on any other single reagent, thus emphasisingthe outstanding versatility of this compound for analytical purposes.Areview of its uses, particularly in p~larography,~~ and a summary of recentanalytical work making use of it 56 have appeared. Measurements havebeen made of its dissociation constant^,^' and the stereochemistry of thecobalt complex has been examined, resolution having been achieved.58Various modifications of existing methods have been devised for thedetermination of calcium in vegetable material,59 or in the presence ofmagnesium and phosphate, separation of the latter being achieved by useof an ion-exchange column,60 of calcium and magnesium in brines,61 inlimestones,62 and in milk; 63 in the last case phosphate is again removed by42 L.L. Merritt, Analyt. Chem., 1953, 25, 718. 43 Analyst, 1953, 78, 586.44 R. S. Nyholm, Quart. Reviews, 1953, 7 , 377. 4 5 J., 1953, 3192.d6 H. Irving and Ii. S. Rossotti, J., 1953, 3397; L. G. Van Uuitert and C. G. Haas,47 C. G. Spike and R. W. Parry, ibid., p. 2726.48 L. G. Van Uitert, W.C. Fernelius, and B. E. Douglas, ibid., p. 3577.48 Idem, ibid., pp. 457, 2736, 2’739; L. G. Van Uitert and W. C. Fernelius, ibid.,51 J. M. Klotz and W.-C. Loh Ming, J . Amer. Chem. Soc., 1953, 75, 4150.52 S. Chaberek, R. C. Courtney, and A. E. Martell, ibid., p. 2185.53 J. F. Steinbach and H. Freiser, Analyt. Chenz., 1953, 25, 881.54 R. 0. Whipple, R. West, and K. Emerson, J., 1953, 3715.5 5 R. L. Pecsok, J . Chem. Educ., 1952, 29, 597.56 M. 0. Lawson, Ind. Ckem. Chem. Manuf., 1953, 29, 299.57 F. F. Carini and A. E. Martell, J . Amer. Chem. SOC., 1953, 75, 4810.58 D. H. Busch and J. C. Bailar, ibid., p. 4574.5s C. C. Strahan and A. W. Moyls, Food Technol., 1952, 6, 333.81 A. de Sousa, Analyt. Chinz. Acta, 1953, 9, 305.6a J. W. Jordan and K.L. Robinson, Chem. and Iizd., 1953, 687; M. D. E. Jonckers,J . Amer. Chem. Soc., 1953, 75, 451.p. 3862. 5O H. Irving, M. J. Cabell, and D. H. Mellor, J., 1953, 3417.G. Brunisholz, M. Gunton, and E. Plattner, Helv. Chim. Acta, 1953, 36, 782.Chim. analyt., 1953, 35, 101. 63 R. Jenness, Analyt. Chem., 1953, 25, 966WILSON : GENERAL. 341ion-exchange. Various interfering elements have been removed as diethyl-dithiocarbamates before calcium and magnesium deterrninati~n,~~, 65 or as8-hydroxyquinoline complexes.65 Magnesium and zinc can be deterrninedtogether by direct titration if the pH is controlled,66 zinc alone being titratedat pH 6.8, and magnesium being subsequently determined at pH 10. Analternative method of control for these two elements uses the zinc ferro-cyanide-ferricyanide system from which the reagent removes zinc, the endpoint being marked by 3 : 3’-dimethylnaphthidine.Magnesium can thenbe titrated in the ordinary way.67 Zinc can be titrated in aluminium andaluminium alloys if the effect of aluminium is prevented by complexingwith citric acid or citrate.68 Although an amperometric titration has beenrecommended for the titration of zinc with ethylenediaminetetra-acetic acid,69it is claimed that the visual end-point obtained by using the usual Solochrome-black indicator is equally go0d.70 Use has been made of the fact that zincand cadmium complexes with cyanide are decomposed by formaldehyde,whereas the cyanide complexes of other metals are more stable, to enabledetermination of these elements in the presence of other heavy metals.71By back titration with thorium nitrate of excess of ethylenediaminetetra-acetic acid, thorium 72, 73 and aluminium 73 have been determined, alizarin-Sbeing used as indicator. Cyanide has been used to mask other heavymetals in the titration of lead 74 and mangane~e.7~ Manganese has alsobeen determined by precipitation as sulphide before t i t r a t i ~ n .~ ~ In thetitration of indium 779 78 tartrate and cyanide are used to prevent interferences.In the titration of iron it is claimed 79 that when thiocyanate is used asindicator the end-point is dependent on the concentration of thiocyanate.Disodium 1 : 2-dihydroxybenzene-3 : 5-disnlphonate and salicylic acid havebeen recommended as alternative indicators to thiocyanate.80 Iron andcopper together can be determined by using photometric end-poink8l> 82Titanium is precipitated from solutions containing ethylenediaminetetra-acetic acid which have been rendered ammoniacal and set aside.83 Ifmagnesium is also present the precipitate is crystalline and contain mag-nesium together with all of the titanium.The titanium in this precipitatecan then be determined in the usual fashion as the per-complex. Sulphatecan be determined indirectly by addition of excess of barium chloride anddetermination of the excess of barium.84 Fluoride can likewise be deter-64 K. L. Cheng, s. W. Melsted, and R. H. Bray, Soil Sci., 1953, 75, 37.65 W. A. Forster, Analyst, 1953, 78, 179.6 6 E.G. Brown and T. J. Hayes, Analyt. Chiw. Acta, 1953, 9, 1.68 F. E. Faller, 2. anal. Chem., 1953, 139, 15.69 D. Pickles and C. C. Washbrook, Analyst, 1953, 78, 304.70 N. Straiford, ibid., p. 733.72 K. Ter Haar and J. Bazen, Analyt. Chim. Acta, 1953, 9, 235.7 3 13. Flaschka, K. Ter Haar, and J. Bazen, Mikrochim. Acta, 1953, 346.74 H. Flaschka and F. Huditz, 2. anal. Chem., 1952-1953, 137, 172.75 H. Flaschka and A. M. Amin, Mikrochim. Acta, 1953, 414.76 W. Pilz, Moflatsh., 1952, 83, 1291.7 7 H. Flaschka and A. M. Amin, Mikrochim. Acba, 1953, 410.7 8 Idem, 2. anal. Chew., 1953, 139, 6.79 D. Lydersen and 0. Gjems, zbid., 138, 249.8o K. L. Cheng, R. H..Bray, and T. Kurtz, Analyt. Chem., 1953, 25, 347.A. L. Underwood, zbzd., p. 1910.82 P. B.Sweetser and C. E. Bricker, ibid., p. 253.83 W. F. Pickering, Analyt. Chim. Acta, 1953, 9, 324.K. E. Langford, Electroplating, 1953, 6, 41, 68.Idem, ibid., p. 6.71 H. Flaschka, 2. anal. Ckem., 1953, 138, 332342 ANALYTICAL CHEMISTRY.mined by precipitation with excess of standard calcium chloride solution. 85Tungsten can be determined by precipitation as calcium tungstate, solutionof the precipitate, and decomposition to give calcium chloride and tungsticacid. After removal of the latter the filtrate containing calcium equivalentto the tungsten is titrated.86 Palladium is determined through thenickel equivalent liberated on addition to a solution of complex nickelcyanide. 87Ethylenediaminetetra-acetic acid has been used to prevent interferenceof other metals in the determination of copper by diethyldithiocarbamate.88~ 89The polarography of solutions of ethylenediaminetetra-acetic acid con-taining copperJgO mercuryJgl and vanadiumg2 has been studied, and it issuggested that the indirect determination of calcium, magnesium , and ironthrough the waves given by anodic depolarisation should be possible.93 Theabsorption spectra of complexes formed with chromium have been relatedto pH.94The separation of lanthanon mixtures into enriched fractionsJg5 basedon the considerable differences in stabilities of the complexes with ethylene-diaminetetra-acetic acid 96 and the consequent separation on an ion-exchangecolumn, has been reported.For separation of certain lanthanon pairs onion-exchange columns it is pointed out that the most efficient pH rangecannot be used to advantage because of the low solubility in this range.97Fractionation using the method of precipitation in homogeneous solutionhas achieved preferential precipitation of the lanthanons of lower atomicnumber by complexing of the o x a l a t e ~ .~ ~ This arises from the fact that,although the solubilities of the oxalates decrease with increasing atomicnumber, the stabilities of the ethylenediaminetetra-acetic acid complexesincrease. These separations, which are in the reverse order from thoseachieved by normal methods, are comparable with them in efficiency.The copper complex in alkaline solution is foundg9 to behave in rathersimilar fashion to Benedict’s solution in the qualitative test for reducingsugars.Although it has been found that ethylenediaminetetra-acetic acid alonegives a poor separation of iron and manganese before the determination ofniobium and tantalum,lOO yet when the reagent is mixed with chelatingagents of the iminodiacetic acid type (not more fully formulated) muchbetter separations, capable of being usefully employed analytically, areachieved.The ethylenediamine-di- and -tetra-propionic acids have also been85 R.Belcher and S. J. Clark, Analyt. Chim. A d a , 1953, 8, 222.8 6 A. de Sousa, ibid., 9, 309.K. L. Cheng and R. H. Bray, Analyt. Chem., 1953, 25, 655.89 A. Jewsbury, Analyst, 1953, 78, 363; W. A. Forster, ibid., p. 614.R. L. Pecsok, Analyt. Chem., 1953, 25, 561.91 J.Goffart, G. Michel, and G. Duyckaerts, Analyt. Chim. Ada, 1953, 9, 184.92 R. L. Pecsok and R. S. Juvet, J . Amer. Chem. Soc., 1953, 75, 1202.93 D. Lydersen, 2. anal. Chem., 1953, 139, 327.9 4 R. E. Hamm, J . Amer. Chem. Soc., 1953, 75, 5670.O 5 E. J. Wheelwright and F. H. Spedding, ibid., p. 2529.O 6 E. J. Wheelwright, F. H. Spedding, and G. Schwarzenbach, ibid., p. 4196.9 7 S. W. Mayer and E. C. Freiling, ibid., p. 5647.9 8 L. Gordon and K. J. Shaver, Analyt. Claem., 1953, 25, 784.99 13. Wagreich and B. Harrow, ibid., p. 1925.loo C. F. Hiskey and ,4. L. Batik, ibid., p. 823.87 H. Flaschka, Mikrochim. Acta, 1953, 226WILSON INORGANIC QUALITATIVE ANALYSIS. 343studied,lol and complexing is found to occur less effectively on replacementof acetate by propionate.The acid dissociation constants of nitrilotri-carboxylic acids, compounds which have many similarities in action toethylenediaminetetra-acetic acid, have been measured. lo2Of certain p-diketones investigated for the extraction of zirconium andhafnium from perchloric acid solution, benzene solutions of 2-thenoyltri-fluoroacetone and 2-furoyltrifluoroacetone have been found lo3 to be themost satisfactory, and the former is stated to be preferable since the diketonehas a more satisfactory partition coefficient.3. INORGANIC QUALITATIVE ANALYSIS.The classical scheme, using hydrogen sulphide, for the semimicro-analysis of cations has been extended to include all the elements likely to bemet with in modern analytical practice.104 An apparatus has been describedfor the passage of gas into small volumes of liquid down to one drop.lo5 Amodified scheme of analysis has been devised which utilises precipitationof thio-salts of elements of the arsenic group and vanadium on addition ofammonium sulphide, these compounds being subsequently decomposed tosulphides on treatment with hydrochloric acid.lo6 The method is claimedto be preferable to the use of hydrogen sulphide, and the scheme includessome of the less familiar elements.An aqueous-ethanolic solution of p-naphthyl sulphide has been recom-mended as a reagent for certain heavy metals.107 A.Sykes has reviewedthe precipitation of sulphides by reagents other than hydrogen sulphide.lo8A systematic analysis of the cations is based on basic benzoate andfluoride precipitations, and eliminates the normal sulphide separation.logh i o i i s can be separated into seven groups and identified within the groupsby specific tests by utilising the insolubility of the salts of lithium, calcium,barium, zinc, and lead.l1°E.Dannenberg ll1 has recommended the impregnation of appropriatecarriers such as paper and silica granules with an extensive series of thereagents required in inorganic analysis. In this way small volumes ofsolution may be analysed reliably and with economy. A number of tests forthe identification by fluorescence of ammonium, potassium, sodium, iron,and cadmium ions have been described. 112 Electrographic methods ofanalysis have been reviewed briefly 113 and their use in the identification ofalloys has been described.ll* Electrolytic methods of detection on theultramicro-scale may be employed for the detection of g.ina volume of ml.115toIo1 R. C. Courtney, S. Chaberek, andA. E. Martell, J . Amer. Chem. Soc., 1953, 75, 4814.lo2 S. Chaberek and A. E. Martell, ibid., p. 2888.lo3 E. M. Larsen and G. Terrey, ibid., p. 1560.lo4 H. Holness and K. R. Lawrence, Analyst, 1953, 78, 356.lo5 H. Weisz, Mikrochim. Acta, 1953, 14.lo6 I. K. Taimni and R. P. Agarwal, A9zaZyt. Chim. A d a , 1953, 9, 208.lo7 J. W. Airan and D. S. Wagle, Curr. Sci., 1953, 21, 339.log Ind. Chem. Chem. Manuf.., 1953, 29, 201, 256.log P. W. West, M. M. Vick, and A. L. LeRosen, “ Qualitative Analysis and Analyti-110 C. Malen and P.B6villard, Analyt. Chim. Acta, 1953, 8, 493.113 P. R. Monk, Analyst, 1953, 78, 141.115 I. P. Alimarin and M. N. Petrikova, J . Anal. Chem., U.S.S.R., 1953, 8, 11.cal Separations,” New York, 1953.Ibid., p. 310. I<. P. Stolyarov, J . Anal. Chem. U.S.S.R., 1952, 7, 195.114 G. C. Clarkand E. E. Hale, ibid., p. 145344 ANALYTICAL CHEMISTRY.M. Kohn 116 has examined the coloration by several transition elementsof melted polyphosphates, and on the basis of his examination has proposedmechanisms for the well-known microcosmic salt bead test.A colour reaction for fluoride in the presence of a number of interferingions is carried out with titanium and chromotropic acid on Cel10phane.l~~Hydrazine can be detected on filter-paper by condensation with ?-dimethyl-aminobenzaldehyde to give a coloured product which is adsorbed practicallyirreversibly, although water-soluble.ll* Nitrite can be distinguished fromnitrate by its reaction with 2-amino-4-chloromethylthiazole hydrochl~ride.~~~Instead of the usual Griess-Ilosvay test, the product from the diazotisationof sulphanilic acid can be coupled with cc-naphthol to give a sensitive test.lZ0If nitrate is reduced by means of zinc dust within a narrow pH range (4-5),and the excess of zinc dust is removed, the test can also be applied to this ion.Tellurium in lead-tellurium alloys is dissolved, and precipitated from solution by stannouschloride as colloidal element.122 Germanium can be identified by phenyl-fluorone.121 R.J. Winterton 123 has studied sodium cobaltithiosulphate,sodium calcium ferrocyanide, and sodium uranyl chromate as reagents forpotassium as compared with the more usual sodium cobaltinitrite.Thesensitivities are found to be poor in comparison, but the first and third ofthese reagents may have some use for the detection of potassium in thepresence of ammonium ion. The separation of calcium and strontium byconcentrated nitric acid has been found satisfactory on the semimicro-~ca1e.l~~Beryllium can readily be identified in minerals by the test with quina1i~arin.l~~The test for zinc by precipitation as the double mercury thiocyanate in thepresence of small amounts of cobalt is improved if small amounts of nickelare added in addition to the cobalt.lZ6 If zinc is not present the presenceof the nickel delays the precipitation of cobalt mercuric thiocyanate, prevent-ing any possibility of a misleading resdt.Morpholine has been recom-mended for the detection of cadmium.127 The palladous chloride test formercury has been rendered more sensitive by first collecting the mercuryvapour on gold leaf.128 A procedure has been described for the separationand identification of mercury in systematic analysis on microgram samples.12’The mercurous ion has been identified by reduction of iron(II1) in the presenceof thiocyanate, the iron(11) ion produced being then identified by suitablereagents such as 1 : lO-phenanthr~Iine.~~~The reactions involved in the complexing of copper in ammoniacalsolution by the addition of sodium cyanide have been examined.131 Alizarin-Selenium can be detected by diaminobenzidine.116 Analyt.Chim. Acta, 1953, 9, 226.117 A. K. Babko and P. V. Khodulina, J . Anal. Chem., U.S.S.R., 1952, 7, 281.118 F. Feigl and W. A. Mannheimer, Mikrochem. Mikrochim. Acta, 1952-1 953,40,355.l 1 9 A. L. Misra, R. C. Mehrotra, and J. D. Tewari, 2. anal. Chem., 1953, 139, 89.120 P. Woodward, Analyst, 1953, 78, 727.121 J. Gillis, Analyt. Chim. Acta, 1953, 8, 97.122 E. G. Brown, Analyst, 1953, 78, 623.124 R. B. Hahn, J . Chevn. Educ., 1953, 30, 349.125 F. Feigl and L. Baumfeld, Anal. Assoc. quim. B r a d , 1951, 10, 13.lZ6 F. E. Brown and J. S. Proctor, Analyt. Chem., 1953, 25, 1122.12’ M. V. Rodina, J . Anal. Chem., U.S.S.R., 1952, 7, 312.128 G.Sachs, Analyst, 1953, 78, 185.129 H. M. El-Badry and C. L. Wilson, Mikrochem. Mikrochim. Acta, 1952-1953, 40,131 R. K. McAIpine, Analyt. Chem., 1953, 25, 331.la3 Analyt. Chim. Acta, 1953, 8, 1.218. 130 F. Lucena-Conde, Anal. Soc. es$. Fis. Quim., 1953, 49, B, 45WILSON : INORGANIC GRAVIMETRIC ANALYSIS. 345blue 132 and o-hydroxyphenylfluorone l 2 l have been recommended as reagentsfor the detection of copper. Silver has been separated and identified on themicrogram scale.129 Diphenyl phosphate has been used for the identificationof aluminium 133 and 2 : 5-dihydroxy-1 : 4-benzoquinone for the identi-fication of scandium.l3* The lanthanons can be detected as a group byusing o-arsenobenzeneazo-Z’-l‘ : 8’-dihydroxynaphthalene-3’ : 6’-disulphonicacid l35 and tests for individual members of the group have been described.136Thallium thiourea perchlorate crystals can be used to identify thalliumunder the microscope in the presence of considerable excess of many otherelements, including lead.137 By a suitable procedure interfering ions canbe removed, allowing iron to be identified by S-hydroxyq~inoline.~~~ Analmost specific coloration is given by iron with the dye 5-3’-carboxy-2’-hydroxy-1 ’-methylazobenzeiie-4-sulphonic acid, only palladium and uraniumgiving similar reactions.139 Diphenyl phosphate gives a very sensitivereaction with iron.133 Cobalt can be detected as the green peroxy-complexformed in the presence of sodium hydrogen carbonate 140 or as the char-acteristic crystalline precipitate formed with hydro~yiminodirnedone.~~~An acetone solution of diphenylglyoxime has been recommended 142 for thedetection of nickel. Molybdenum can be detected by the decolorisation ofmethylene-bl~e,~~~ by the red complex formed with gossyp01,l~~ or by thereaction with o-hydroxyphenylfluorone.Ul Tungsten has been separatedon the microgram scale,129 and can be identified with ammonium thiocyanate,st annous chloride, and ammonium bifluoride.145 8-H ydroxyquinoline canbe applied as a field test for uranium.146 Tin can be detected by the fluor-escence given with 6-nitro-2-naphthylamine-8-sulphonic acid. 14’ The separ-ation and identification of lead on the microgram scale has been d e s ~ r i b e d . ~ ~The test for titanium with diphenyl phosphate is stated to be particularlysensitive, so that after precipitation it is impossible to detect titanium in theresidual solution by the usual peroxide test.133 Bismuth can be detectedeither by morpholine and potassium iodide or by diphenyl ~ h 0 s p h a t e .l ~ ~4. INORGANIC GRAVIMETRIC ANALYSIS.A quartz-fibre microbalance has been adapted to carry light absorptiontubes and other relatively bulky objects.148 It is claimed that it will carrya 5-g. load and will give a reproducibility of & 0.26 pg. when carrying aplatinum boat weighing 0-4 g. Special attention has been paid to vibration-free mounting and it is proposed to use the balance for organic analyses inF. Feigl and A. Caldas, Analyt. Chirn. Acta, 1953, 8, 117.133 F. Knotz, Anal.SOC. esp. Fis. Quim., 1952, 48, B , 564.134 L. Pokras and &I. Kilpatrick, AnaZyt. Chenz., 1953, 25, 1270.135 V. I. Kuznetsov, J . Anal. Chem., U.S.S.R., 1952, 7, 226.136 L. M. Kulberg and M. N. Ambrozhy, ibid., p. 233.l37 C. Mahr and H. Klamberg, Mikrochem. Mikrochtim. Actu, 1952-1953, 40, 390.138 A. de Sousa, ibid., p. 265.140 A. de Sousa, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 352.141 J. Gillis, J. Hoste. and J. Pijck, Mikrochim. Acta, 1953, 244.142 W. Wawrzynek, Roczn. Chem., 1952, 26, 668.la3 F. Feigl and L. Baumfeld, Anal. Assoc. quim. B r a d , 1951, 10, 14.144 A. Vioque-Pizarro and H. Malissa, Mikrochem. Mikrochim. Acta, 1952-1 953, 40,145 R. Vanossi, Anal. Asoc. quim., Argent., 1952, 40, 176.l4O A. de Sousa, Mikrochem. Mikrochim.Acta, 1952-1953, 40, 319.147 J. R. A. Anderson and J. L. Garnett, Amzlyt. Chim. Actu, 1963, 8, 393.148 J. A. Kuck, P. L. Altieri, and A. K. Towne, Mikrochim. Acta, 1953, 254.130 C. Ott, Ann. Chim. analyt., 1953, 35, 149.396346 ANALYTICAL CHEMISTRY.the ultramicro-range (< g.). A differential thermobalance has beendescribed which carries two exactly similar samples held at temperatures4” apart.149 It gives a direct photographic record of the change of masswith temperature, registered as a function of time and therefore as a functionof temperature. The mode of use of the Chevenard thermobalance, andresults obtained from it in an extensive series of studies of substances ofanalytical interest, have been published in book form.150 A statisticalinvestigation of the use of the ordinary microchemical balance has shownthat the estimation of fractional divisions on the balance scale is subject toindividual preference to such an extent that errors of up to 0.25% may beintroduced into the ordinary carbon and hydrogen determination.l51 A.-G.Loscalzo and A.A. Benedetti-Pichler 152 have checked Gauss’s double-weighing method against single-weighing technique, both for a standardanalytical balance and for a microchemical balance, and have confirmed thatthe precision is approximately doubled by using the former method.G. Kainz 153 has described a micro-filter which uses a coarse layer ofmaterial such as cotton wool or sea sand as a pre-filtering layer, followedby a fine layer of cellulose powder or asbestos which because of the protectionremains intact for many filtrations. Crucibles for microchemical analysishave been standardised.154 A investigation of the behaviour of titanium,vanadium, and zirconium towards fusion reagents suggests that crucibles ofzirconium might be very satisfactory for sodium hydroxide f u ~ i 0 n s . l ~ ~Precipitation in Homogeneous Solution.-Unexpectedly little fresh workutilising this method appears to have been done. Aluminium, when pre-cipitated in homogeneous solution as the 8-hydroxyquinoline complex, bythe hydrolysis of urea, gives a precipitate of excellent analytical q ~ a 1 i t y . l ~ ~Co-precipitation of iron, manganese, and nickel are found to interfere withthe precipitation of tin from a sulphate solution by hydrolysis of urea.157Also, although the precipitate is excellent in character, it appears to be thebasic sulphate rather than the basic oxide, and cannot be used directly fordetermination of tin.Lead can be determined as sulphate by the hydrolysisof dimethyl s ~ 1 p h a t e . l ~ ~ If barium-radium mixtures are fractionally pre-cipit ated from homogeneous solution as chromates, radium is found concen-trated in the ~rysta1s.l~~ Two ingenious methods suggest that the principleof precipitation in homogeneous solution is capable of very considerableextension through intelligent use of reactions previously considered to berelatively unimportant from the analytical standpcjint. In the first of thesecerium is separated from the other lanthanons by oxidation in the presenceof potassium iodate, by using persulphate, from cei-ium(m), whose iodate issoluble, to cerium(1v) whose iodate is insoluble.160 Thorium iodate is normallymost unsatisfactory as an analytical precipitate, since it is exceedingly149 W.L. De P y s e r , Nature, 1953, 172, 364.1x1 C. Duval,151 H. Gysel, Mikrochim. Acta, 1953, 266.lS2 Mikrochem. Mikrochim. Acta, 1952-1953, 40, 232.153 Microchim. Acta, 1953, 119.155 R. S. Young and K. G. A. Straclian, Chewz. and Ind., 1953, 154.156 K. E. Stumpf, 2. anal. Chem., 1953, 138, 30.15‘ H. H. Willard and L. Gordon, Analyt. Chew., 1953, 25, 170.158 P. J. Elving and W. C. Zook, ibid., p. 502.lS9 M. L. Salutsky, J. G. Stites, and A. W. Martin, ibid., p.1677.le0 H. H. Willard and S. T. Yu, ibid., p. 1754.Inorganic Thermogravimetric Analysis,” London, 1953.1 5 4 B.S.I. Specif., 1953, No. 1428, Pt. E 1LVILSON : INORGANIC GRAVIMETRIC ANALYSIS. 347gelatinous and difficult to manipulate. An excellent form of precipitate is,however, achieved if the iodate is precipitated in homogeneous solution,either by oxidation of iodide, or preferably by reduction of periodate.161In the latter case 2-hydroxyethyl acetate is hydrolysed to ethylene glycol;this in turn reduces the periodate to iodate. The precipitate of thoriumiodate is dense and granular, and a double precipitation by this methodgives quantitative separation from large amounts of lanthanons and phos-phate. Co-precipitation in homogeneous solution of manganese with basicstannic sulphate and of strontium with barium sulphate have been studied.162Methods of Analysis.-Arsenic has been precipitated as the thio-salt andconverted into sulphide by 164 The nature of barium sulphateprecipitates produced under varying conditions has been studied by lightand electron-microscopic examination, 165 and on the basis of this examin-ation a rapid method has been proposed for the determination of sulphate.Adsorption on barium sulphate precipitates has also been studied byX-ray methods.166 The thermogravimetric curve for the decomposition ofocta-ammino-p-ammino-p-nitrodicobaltic sulphate has been determined.167Selenium has been determined as mercuric selenite,lG8 or as the element, pre-cipit ated by reduction with sulphur dioxide in hydrochloric-perchloric acids01ution.l~~ This method is also applicable to the determination of tellurium.Selenium and tellurium have also been determined as sulphides through thethi0-sa1ts.l~~ The precipitation of silica as the complex quinoline silicoinolyb-date has been utilised satisfactorily,170 but the complex formed with 2 : 4-di-methylquinoline is stated to be slightly hygroscopic and, rather than weigh-ing it directly, it is preferable to convert it into the anhydride by ignition at500-560".171 Germanium is precipitated by o-dihydro~yphenols.~~~ Avery satisfactory factor is given by precipitation as barium germaniumtartrate 173 and the determination by this method can be carried out evenin the presence of a considerable amount of arsenite.Radiochemical methods have been used to investigate the best conditionsfor the precipitation of potassium, rubidium, and czsium as the tetraphenyl-boron and a method has been described 175 for the determin-ation of potassium and ammonkm together by precipitation of both ions asthe tetraphenylboron compounds and subsequent extraction of the ammon-ium salt by alkaline acetone, in which the potassium compound is insoluble.Potassium has also been precipitated as the 1Qphosphomolybdate 17G or as161 C.R. Stine and L. Gordon, Analyt. Chem., 1953, 25, 1519.162 L. Gordon, C. C. Reimer, and H. Teicher, ibid., p. 838.163 I. K. Taimni and R. P. Agarwal, Analyt. Chim. Ada, 1953, 9, 116.164 Idem, ibid., p.121.165 R. B. Fischer and T. B. Rhinehammer, Analyt. Chem., 1953, 25, 1544.C. A. Streuli, H. A. Scheraga, and M. L. Nichols, ibid., p. 306.167 D. Gibbons, J., 1953, 1641.168 G. S. Deshmukh and K. M. Sankaranarayanan, J . Indian Chem. SOC., 1952, 29,527.169 H. Got6 and Y . Kahita, Sci. Rep. Res. Inst. TGhoku Univ., 1952, 4, 28; H. Got6171 C. C. Miller and R. A. Chalmers, Analyst, 1953, 78, 24.172 P. Bkvillard, Comfit. rend., 1952, 234, 216.173 G. N. Schrauzer, Mikrochim. Acta, 1953, 124.17* W. Geilmann and W. Gebauhr, 2. anal. Chew., 1953, 139, 162.175 hl. Kohler, i b i d . , 1953, 138, 9.1 7 6 R. Belcher and J. W. Robinson, A.tzaZyt. Chinz. Acta, 1953, 8, 239.and T. Ogawa, ibid., p. 121.M. Armand and J. Berthoux, Analyt. Chim. Acta, 1953, 8, 510348 ANALYTICAL CHEMISTRY.a precipitate with the definite composition K3[Co(N0&] ,2H,O, formed byprecipitation with lithium cobaltinitrite.177 Caution is advised in the useof alcoholic solutions of reagents in the determination of sodium by tripleacetate formation since the formula of the precipitate is rendered even moreuncertain through variable replacement of water molecules by alcoholrn0lecu1es.l~~ Sodium can be determined as the triple acetate in potassiumsalts if the potassium is first precipitated as perchlorate and filteredLithium can be precipitated as trilithium phosphate by using choline phos-phate in isopropanol as reagent.lsO Anhydrous calcium oxalate is notrecommended as a weighing form since it is sufficiently hygroscopic to revertslowly to the monohydrate.lS1 The gravimetric determination of stron-tium l*2 and of barium 183 as oxalates has been investigated. Zinc is pre-cipitated by 5 : 6-benzoquinaldinic acid as the compound Zn(C,,H8N0,)2,H,0which may be dried a t 110-115" and weighed.184 The corresponding cad-mium compound contains 1.5 molecules of water, but is anhydrous a t 125-130°, so that drying a t a temperature somewhat above this enables theelement to be determined.ls5 Zinc and cadmium can be separated byutilising the precipitation of cadmium metal from a solution containingpotassium cyanide and potassium sodium tartrate by metallic copperprepared by reduction of copper oxide.ls6 In these conditions zinc is notprecipitated. A complex bromide is formed by cadmium in the presenceof potassium bromide with diantipyrinyl-o-hydro~ypheny1methane.l~~Mercury can be determined as the complex with Z-o-hydroxyphenylbenz-iminazole.Alizarin-blue 189 and the sodium salt of N-(N-bromo-C-tetradecyl-bet ainy1)-C-tetradecylbetaine lS0 have been recommended for the gravimetricdetermination of gold.This element has been separated from platinum-metal mixtures and determined by quin01.l~~In the analysis of silicate rocks, aluminium has finally been determinedas 8-hydroxyquinoline complex after extraction together with beryllium byusing acetylacetone.lQ2 Other interfering elements are first extracted as thecupferron complexes by using o-dichlorobenzene. Means of reducing errorsdue to co-precipitation in the determination of gallium by cupferron havebeen recommended.lQ3 The manganese complex of 5 : 6-benzoquinaldinicacid 184 has the formula Mn(C,,H8N0,),,2.5H,0. A reagent for ironwhich is a t least as sensitive as the naphthyl analogue of cupferron177 T. Dupuis, Analyt. Chim. Acta., 1953 9, 493.L. B. Rogers and G. P. Haight, ibid., 1952, 7 , 501.179 C. Jackson, Analyst, 1953, 78, 599.180 E. R. Caley and G. A. Simmons, Analyt. Chem., 1953, 25, 1386.C. C. Miller, Analyst, 1953, 78, 186.T. Matsumoto, Bull. Chem. Soe. Japan, 1952, 25, 242.183 Idem, ibid., p. 361.184 A. K. Majumdar and A. K. De, J . Indian Chem. SOC., 1953, 30, 123.las Idem, ibid., 1952, 29, 499.A. Bryson and S . L. Lowy, Analyst, 1953, 78, 299.Is' V. I. Kumov, J .Anal. Chem., U.S.S.R., 1952, 7 , 301.l a 8 J. L. Walter and H. Freiser, Analyt. Chem., 1953, 25, 127.F. Feigl and A. Caldas, Analyt. Chim. Acta, 1953, 8, 339.loo A. E. Harvey and1 9 1 R. R. Barefoot and F. E. Beamish, ibid., 9, 49.Is* C. C. Miller and R. A. Chalmers, Analyst, 1953, 78, 686.loS E. Gastinger, 2. anal. Chem., 1953, 139, 1.. H. Yoe, Analyt. Chim. Acta, 1953, 8, 246WILSON INORGANIC GRAVIMETRIC ANALYSIS. 349(neocupferron) has been prepared by replacing the benzene nucleus in cup-ferron by the fluorene nucleus to give the 2-fluorenyl derivative.lg4 Di-antipyrinylphenylmethane gives a complex ferricyanide which may be usedfor the gravimetric determination of ferricyanide.lg5 Ferrocyanide does notreact. For the gravimetric determination of cobalt the complex with5 : 6-benzoquinaldinic acid, which has the formula Co (C,,H,02N),,2H 20,can be used.ls4 The corresponding nickel complex, like the manganese one,contains 2.5 molecules of water.Determination of nickel can be carriedout as accurately with resacetophenone oxime as with dimethyl-g l y o x i ~ x e . ~ ~ ~ ~ 197 A standard method for the determination of molybdenumin low-alloy steeIs has been pub1i~hed.l~~ Molybdenum can also be deter-mined as the sulphide, MoS3,2H,O, after precipitation as a t h i o - ~ a l t , ~ ~ ~ ? lD9or as the oxide after precipitation as sulphide in the normal fashion 2oo orby use of thiosulphate as precipitant .,O1 Treatment with thiofonnamideprecipitates tin as the anhydrous sulphide which can then be dried andweighed,,02 Tin, precipitated by ammonium sulphide as the thio-salt, canbe converted into the sulphide SnS2,2H20 for weighing; lg9 or it can beprecipitated from hydrochloric acid solution by N-benzoylphenylhydroxyl-amine as the complex chloride, which is then ignited and weighed as oxide,or is dried at 110" and weighed as (Cu,,HI,O,N),SnCl2, which has a muchmore favourable factor.203 Separations of zirconium with mandelic acid 204or with P-chloromandelic or $-bromomandelic acid 205 have been proposed.A study of the solubility of thorium oxalate under analytical conditionssuggests that this form is not suitable if other means of precipitation areavailable.,06 Reagents proposed for the gravimetric determination ofthorium include stearic, pyrogallic, and m-hydroxybenzoic acids 207 andvanillic acid.208 The thermogravimetric curve for dichlorobisethylene-diaminecobaltic hexachlorostibnate has been determined.167 Precipitationof antimony with thioformamide is preferred to precipitation with hydrogensulphide.202 The red modification of sulphide which is obtained in thisprecipitation is converted into the black modification for weighing. Bismuthhas been determined by benzidine in the presence of potassium iodide209or by trimethylphenylammonium iodide.2lO Direct combustion in oxygento the textroxide, absorption in potassium hydroxide, and weighing has beenutilised for the determination of osmium.211 Both thioglycollic-p-amino-naphthalide (thionalide) and 2-phenylbenzothiazole have been recom-lS4 R.E. Oesper and R. E. Fulmer, Analyt. Chem., 1953, 25, 908.1B5 S. I. Gusev and R. G. Beyles, J . Anal. Chem., U.S.S.R., 1952, 7, 219.lS6 K. S. Bhatki and M. B. Kabadi, J . Sci. Ind. Res. India, 1952, 11, B, 346.Is' Idem, ibid., 1953, 12, B, 226.lSs I. K. Taimni and R. P. Agarwal, Analyt. Chim. Acta, 1953, 9, 203.201 H. N. Rby, Analyst, 1953, 78, 217.202 A. Musil, E. Gagliardi, and K. Reischl, 2. anal. Chem., 1052-1953, 137, 252.203 D. E. Ryan and G. D. Lutwick, Canadian J . Chem., 1953, 31, 9.204 E. C. Mills and S. E. Hermon, Analyst, 1953, 78, 256.205 R. A. Papucci, D. M. Fleishman, and J. J. Klingenberg, Analyt. Cheutz., 1953, 25,206 H. L. Kall and L. Gordon, ibid., p. 1256.207 G. S. Deshnukh and J. Xavier, J .Indian Chern. Soc., 1952, 29, 911.208 K. V. S. Krishnamurty and A. Purishottam, Rec. Trav. chim., 1952, 71, 671.20s G. I. Barannikov, J . Anal. Chem., U.S.S.R., 1952, 7, 239.210 T. S. Burkhalter and J. F. Solarek, Amlyt. Chem., 1953, 25, 1125.211 A. ILlusil and R. Pietsch, Z. anal. Chem., 1952-1953, 137, 321.lo* B.S.I. Specif., 1952, 1121, Pt. 26.J. Ibarz Azn&rez and P. Mirb Plans, Anal. Soc. esp. Fis. Qztim., 1952, 48, B, 758.1758350 ANALYTICAL CHEMISTRY.mended 212 as organic reagents suitable for the gravimetric determination ofosmium, the latter being rather more rapid. Strychnine sulphate may alsobe used for the same purpose, although its use is not quite so straightforward.Platinum can be determined as sulphide through the thio-salt 163 or can beseparated from gold and palladium by reduction with zinc.lg1 In suchmixtures 191 or in mixtures of other platinum metals 213 palladium is deter-mined as the dimethylglyoxime precipitate.5. INORGANIC TITRIMETRIC ANALYSIS.K.F. Korner 214 has described a burette with interchangeable graduatedportions which can be used for either macro- or micro-titrations. An air-controlled and an oil-controlled micro-burette having the convenience of stop-cock control have been devised.215 The principle of supplying standard acidor alkali derived, by passage through an ion-exchange column, from a singlepotassium chloride solution, has been applied to simplified micro-burettes ofthe horizontal type.216 An apparatus has been described 217 which simplifiestitrations, such as that of Karl Fischer, which must be carried out in acontrolled atmosphere.K.F. Korner 218 has discussed the dependence of titration errors on thetitrating solutions, and has shown how errors arising from different methodsof analysis may be converted to comparable forms. It has been shown 219that over extremely wide variations of sulphuric acid concentration thepermanganate-oxalate titration has little or no dependence on the acidconcentration. Methods for standardising titanous solutions, particularlyin the presence of traces of iron, have been examined,220 and it is claimed thatfor most purposes standard titanous chloride is preferable to standardtitanous sulphate. Potassium metaperiodate 221-223 and iodine trichloridein hydrochloric acid224 have been applied to a wide variety of titrimetricdeterminations.It has been shown 225 that in the presence of thiocyanatethe greatly enhanced reducing power of metallic mercury can be appliedto the determination of iron and other ions; in particular, ferricyanide canbe quantitatively reduced to ferrocyanide, which can then be titrated withceric solution.J. E. Kunzler 226 has prepared absolute sulphuric acid for use as a primarystandard, and concludes that for a given amount of effort in its preparationa sulphuric acid standard is about ten times as accurate as any previouslyused. Of the various sulphuric acid standards which may be prepared,constant-boiling acid is proposed as that most generally useful. The thermalstability of potassium acid phthalate has been investigated,227 and it is212 I.Hoffman, J. E. Schweitzer, D. E. Ryan, and F. E. Beamish, Analyt. Chem.,1953, 25, 1091. 213 G. H. Ayres and E. W. Berg, ibid., p. 980.214 2. anal. Chem., 1953, 139, 99. U. L. Upson, Analyt. Chem., 1953, 25, 977.216 B. W. Grunbaum and P. L. Kirk, Mikrochem. Mikrochim. Acta, 1952-1 953,40,416.217 R. H. Prince, Analyst, 1953, 78, 607.219 R. C. Brasted, Analyt. Chem., 1953, 25, 673.220 J. J . Lamond, Analyt. Chim. Acta, 1953, 8, 217.221 B. Singh and A. Singh, J. Indian Chem. SOL., 1952, 29, 517.222 Idem, ibid., 1953, 30, 143.224 Y. A. Fialkov and F. E. Kagan, Ukr. Khim. Zhur., 1952, 18, 55.225 F. Burriel-Marti, F. Lucena-Conde, and S. Bolle-Taccheo, Analyt. Chim.A cta,226 Analyt. Chem., 1953, 25, 93.tL7 E. R. Caley and R. H. Brundin, ibid., p. 142.218 2. anal. Chem., 1953, 138, 111.223 Idem, Analyt. Chim. Acta, 1953, 9, 22.1953, 9, 293\VJI,SON : INORGANIC TITRIMETRIC ANALYSIS. 351recommended that a safe upper limit for drying this material before use asa primary standard is 135". G. F. Smith and D. H. Wilkins 228 recommend2 : 4 : 6-tri~itrobenzoic acid as a primary standard in acidimetry. It isa material with a high equivalent, is anhydrous and non-hygroscopic, andserves as its own indicator, although bromothymol-blue may be used formore precise work. It is easily soluble in water, and the reagent and itssolutions are stable on storage. Bariumthiosulphate monohydrate has been discussed 229 as a standard foriodometry.It has a high equivalent and definite composition, is easilyprepared and is highly accurate. On the other hand its solubility is low sothat it must either be used as solid or in very dilute solution ; and its thermalstability is poor, so that it must be dried below 40".Methods of Analysis-The Volhard halide titration has been improvedon the basis of theoretical consideration^.^^^ R. Belcher and R. Goulden 231have used a sparingly soluble iodate to react with chloride and liberate anequivalent amount of iodate ion. After filtration this can be titrated iodo-metrically, giving an amplification factor of 6. Mercuric, mercurous, andsilver iodates are all suitable for the purpose, giving good reproducibilityalthough the accuracy of the titration is not high.Sodium chlorite has beentitrated against standard arsenite in the presence of sodium hydrogencarbonate, osmic acid acting as catalyst .232 Chlorate and perchlorate canbe determined in the presence of one another by reduction of chlorate bymeans of stannous solution, and subsequent reduction of the perchlorate bythe same agent catalysed by molybdate.233 Elementary iodine can be deter-mined 234 by extraction with carbon tetrachloride, conversion into iodide byalkali, and titrimetric determination, with an amplification factor of 36 oreven of 216. The results are as satisfactory as those obtained by distillingthe iodine, and very much superior to those obtained by using active carbonto retain it."5 Special treatment is necessary to release fluorine from veget-able material for d e t e r m i n a t i ~ n , ~ ~ ~ since otherwise calcium may retainfluorine in a form which is non-distillable by the usual methods of determin-ation.Contrary to earlier reports, if the titration of lead chlorofluoride, inthe determination of fluoride by means of Volhard's procedure, is carriedout under proper conditions, there is no pronounced fading at the end-point,237 and any slight fading that may occur can be readily overcome bythe addition of a slight excess of thiocyanate. Elemental fluorine can betitrated against bromine dissolved in bromine trifluoride a t room temper-ature, the end-point being indicated by the disappearance of the brominecolour ; 238 this reaction can also be used to determine bromine or substancessuch as metals, oxides, and halides which yield bromine when treated withbromine trifluoride.It may safely be dried at 130".Analyt.Chim. Acta, 1953, 8, 209.22g W. M. MacNevin and 0. H. Kriege, Analyt. Chem., 1953, 25, 767.2s0 E. Schulek, E. Pungor, and J. Kkthelyi, Analyt. Chim. Acta, 1953, 8, 229.231 Mikrochim. Acta, 1953, 290.233 G. P. Haight, Analyt. Chern., 1953, 25, 642.234 H. Spitzy, H. Skrube, and F. S. Sadek, Mikrochim. Acta, 1953, 375.235 Idem, 2. anal. Chem., 1953, 139, 110.236 L. F. Remmert, T. D. Parks, A. M. Lawrence, and E. H. McBurney, Analyt.237 R. Belcher and P. I. Brewer, Analyt. Chim. Acta, 1953, 8, 235.238 T . Sheft, H. H. Hyman, and J . J. Katz, AiaalyZ.Chenz., 1953, 25, 1877.232 E. G. Brown, Analyt. Chim. Acta, 1952, 7, 494.Chem., 1953, 25, 450352 ANALYTICAL CHEMISTRY.In the determination of ammonia in the presence of hydrazine 239 thelatter may be destroyed by oxidation by iodic acid, bromine, or alkalinepermanganate, before the actual determination. Nitrite can be deter-mined 240 by addition of excess of standard bromine solution in the presenceof pyridine as catalyst, the excess then being determined iodometrically.Nitrate can be estimated in the presence of nitrite by use of ferrous sulphateas reagent,241 but special precautions must be taken to prevent oxidationof nitrite, and in any case an empirical correction must be applied. Whenalkali nitrates or nitrites are heated with formic acid at 550", they are con-verted quantitatively into the corresponding alkali carbonates, which arethen determined titrimetri~ally.~~2 Improved iodometric methods havebeen proposed for the phosphorous acids 243 and for arsenic.24a Arsenite canbe determined by standard chlorite with an osmic acid ~ a t a l y s t .2 ~ ~ In thedetermination of hydrogen peroxide by ceric solution the reactions appear tobe affected by the presence of perchlorate, which forms a stable peroxidecomplex.245 A phosphoric-phosphorous acid mixture has been recommendedfor the liberation of sulphide sulphur before iodometric determinati~n.~~~ Itis claimed,247 however, that although the results in the iodometric deter-mination have a high accuracy, the method has too low sensitivity for certainpurposes, and as an alternative a hypochlorite titration is recommended, anempirical factor being necessary. From a study of the solubilities of amines u l p h a t e ~ , ~ ~ ~ 4-amino-4'-chlorodiphenyl has been developed for the rapidand accurate alkalimetric determination of ~ u l p h a t e , ~ ~ ~ particularly whennitrate is also present.Instead of benzidine, 4 : 4'-diaminotolane has beenrecommended as a precipitating reagent for the titrimetric determination of~ulphate.2~~ Nitrate, chlorate, and a range of metal ions show no inter-ference, and interference from aluminium can be avoided by addition oftartaric acid. For very small amounts of sulphate it is claimed that pre-cipitation and removal of barium sulphate, conversion of excess of bariuminto barium chromate, and determination of the excess of chromate withferrous sulphate avoids errors inherent in the conventional barium sulphaterneth0d.2~~ W.G. Hunt 252 advocates removal of metallic ions in sulphatesolution by passage through an ion-exchange column, before precipitationof the sulphate with excess of barium solution and titration of the excesswith et hylenediaminet etra-acetic acid. Sulphat es, sulphit es, and t hio-sulphates can be determined in mixtures i~dornetrically.~~~ A titrimetricprocedure has been proposed for per~ulphate.2~~ Selenium has been239 W. Pugh and W. K. Heyns, Analyst, 1953, '98, 177.240 J. V. L. Longstaff and K. Singer, ibid., p. 491.241 C. L. Johnson, Analyt. Chem., 1953, 25, 1276.242 F.Feigl and A. Schaeffer, Analyt. Chim. Acta, 1952, 7 , 507.243 R. T. Jones and E. H. Swift, Analyt. Chem., 1953, 25, 1272.244 J. Haslam and N. T. Wilkinson, Analyst, 1953, 78, 390.245 S. Baer and G. Stein, J . , 1953, 3176.246 0. Horak, 2. anal. Chern., 1953, 139, 196.247 P. 0. Bethge, Analyt. Chim. Ada, 1953, 9, 129.248 R. Belcher, M. Kapel, and A. J. Nutten, ibid., 8, 122.24g R. Belcher, A. J. Nutten, and W. I. Stephen, J., 1953, 1334.250 R. Belcher, M. Kapel, and A. J. Nutten, Analyt. Chim. Acta, 1953, 8, 146.e51 W. Geilmann and G. Bretschneider, 2. anal. Chem., 1953, 139, 412.S63 J . Amer. Water Works Ass., 1953, 45, 535.25s R. I. Mamberto, Rev. Fac. Cienc. qulm., La Plata, 1949, 24, 69.254 I. M. Kolthoff and E. M. Carr, AnaZyt.Chem., 1953, 25, 298WILSON : INORGANIC TITRIMETRIC ANALYSIS. 353determined 255 by conversion into selenocyanide, treatment with bromineto give an equivalent amount of cyanogen bromide, and iodometric com-pletion of the determination. Aluminium is removed from aluminium-boron alloys by potassium hydroxide before determination of the boron bya mannitol titration.256 Where silver is present interference is firstprevented by addition of thiosulphate before proceeding with the usualfinish for boron.257Potassium can be determined by precipitation in the presence of organicsolvents as the hydrogen tartrate and titration with alkali.25s Severalmodifications of the titrimetric determination of potassium through thetetraphenylboron compound have been proposed.In the presence of aknown excess of sodium hydroxide the complex may be allowed to react withmercuric chloride ; each g.-atom of potassium liberates three moles ofhydrochloric acid, estimated by titration of the excess of hydr0xide.25~ Onheating a mixture of the ammonium and potassium tetraphenylboron com-plexes, the ammonium compound is volatilised and the potassium compoundis converted into potassium metaborate, which can then be determined bytitration with alkali.260 The precipitation in the presence of ammoniumradical is advocated since it reduces loss in washing and brings down aprecipitate more suitable for filtration. In a third modification the potas-sium is precipitated by excess of sodium tetraphenylboron, and the excess isin turn precipitated by excess standard silver solution.261 The silver remain-ing in solution is then determined by a Volhard titration.Sodium can bedetermined z62 by precipitation as the triple uranyl acetate, followed byreduction of the uranium(v1) to uranium(1v) by chromium(I1) solution. Theexcess of chromium(I1) is destroyed by atmospheric oxidation and theuranium is titrated with ammonium hexanitratocerate.Beryllium can be precipitated as beryllium ammonium arsenate, and thearsenate in the precipitate determined iod~metrically.~~~ Magnesium can beprecipitated as the ammonium phosphate, dissolved in acid, and the excessof acid determined.264The ferrocyanide titration of zinc has been examined critically and aprocedure recommended 265 using diphenylbenzidine as internal indicator.Zinc and cadmium can be precipitated as the basic carbonates266 whichare then determined alkalimetrically, or as the anthrani1ates,z67 which arethen treated with standard bromide-bromate solution and determined bythiosulphate.The precipitate obtained when a cadmium solution is treatedwith diantipyrinyl-o-hydroxyphenylmethane can be dissolved in aqueousethanol in the presence of potassium bromide and titrated with standardalkali, methyl-orange being the indicator.lS7 When mercury salts aretreated with alkali in the presence of aqueous acetone the oxide remains in2 6 5 E. Shulek and E. K6ros, 2. anal. Chem., 1953, 139, 20.256 E. Eipeltauer and G. Jangg, ibid., 138, 18.257 S. Z. Haider, Analyst, 1953, 78, 673.2 5 8 A.F. Ievinsh and Y. K. 0201, J . Anal. Chem., U.S.S.R., 1953, 8, 53.259 H. Flaschka, A. M. Amin, and A. Holasek, 2. anal. Chem., 1953, 138, 241.2-50 Idem, ibid., p. 161.262 P. Trinder, Analyst, 1953, 78,180.264 D. Bourdon, Ann. Chim. analyt., 1952. 34, 221.265 M. R. Richardson and A. Bryson, Analyst, 1953, 78, 291.2 6 6 M. M. Tillu, Analyt. Chim. Ada, 1953, 8, 337.2-57 C. Cimerman and M. Selzer, ibid., 9, 26.261 W. Riidorff and H. Zannier, ibid., 1953, 139, 1.263 R. Airoldi, Ann. Chim. a$pl., 1953, 43, 15.REP.-VOL. L 354 ANALYTICAL CHEMISTRY.solution, but subsequent treatment with either potassium iodide or sodiumthiosulphate releases an equivalent amount of alkali which can be titratedwith acid, phenolphthalein being the indicator.268Mercury and copper can be determined alkalimetrically, with cresol-phthalein as indicator.269 In the former case the colour change correspondsto the formation of HgO, and in the latter to formation of CuS04,3Cu(OH),.The titration of cuprous thiocyanate by iodate has been investigated as ameans of determining milligram and microgram amounts of copper.270 Thiselement can also be determined by titration with dithizone in a homo-geneous acetone-water solution.271 Silver can be determined by iodidetitration in the presence of ammonium acetate, bromophenol-blue beingused as an adsorption indicator,272 or o-dianisidinegold(II1) as an ordinaryindicat0r.~~3Europium can be determined in lanthanon mixtures by passing thesolution through a Jones reductor into excess of ferric chloride solution andtitration with standard dichromate solution.274 There is no interferencefrom samarium or ytterbium, which are not reduced by zinc.The titration of manganese with 8-hydroxyquinoline can be carried outsatisfactorily under certain condition~.~7~ The amount of cuprous iodidenecessary to prevent interference from high concentrations of sulphate inthe iodometric determination of iron has been determined.276 When nickelferricyanide is added to potassium ferrocyanide interchange takes place, andthe equivalent amount of potassium ferricyanide is formed.277 After filtra-tion the ferricyanide can be determined by thiosulphate, thus permittingindirect determination of ferrocyanide.Cobalt, precipitated as the anthr-anilate, can be determined iodometrically after treatment with bromate-bromide Nickel solutions can be titrated directly with alkali ;with cresolphthalein as indicator, the colour change takes place aftercomplete precipitation of the nickel hydroxide.269Tin can be determined by reduction with iron and potassium iodide,followed by titration with standard iodate solution.278 Zirconium can beprecipitated by oxalohydroxamic acid.279 The precipitate is dissolved indilute acid and warmed, oxalic acid and hydroxylamine being produced.The hydroxylamine can then be determined by addition of excess of titanoussolution and back titration with standard iron(m).Thorium can be deter-mined by direct titration with ethylenediaminetetra-acetic acid, alizarin-redS being used as internal indicator.280Titrimetric methods for the determination of antimony have beenreviewed.281 Antimony can be determined, after precipitation with thio-268 M.N. Das, Analyt. Chem., 1953, 25, 1406.269 G. Denk, 2. anal. Chem., 1953, 139, 103.270 K. Tantranon and B. B. Cunningham, Analyt. Chem., 1953, 25, 194.271 R. Delavault and R. Irish, Compt. rend., 1951, 233, 1614.2 i 2 G. Mannelli, Analyt. Chim. Acta, 1953, 9, 232.273 F. Sierra and F. Romojaro, Anal. SOC. esp. Fis. Quim., 1953, 39, B, 131.274 D. G. Foster and H. E. Kremers, AnaZyt. Chew., 1953, 25, 1921.2 7 j K. Neelakantam and K. Parthasarathi, Proc. Indian Acad. Sci., 1952, 36, A , 123.2 7 6 E. W. Hammock and E. H.Swift, Analyt. Chem., 1953, 25, 1113.277 M. Kohn, Analyt. Chinz. Acta, 1953, 8, 317.278 C. Cimerman and hi. Ariel, ibid., 9, 10.279 S. K. Dhar and A. K. Das Gupta, J . Sci. I n d . Res.. India, 1952, 11, B, 500.2so J. J..Fritz and J. J. Ford, Analyt. Chem., 1953, 25, 1640.281 D. Gibbons, Ind. Chem. Chena. Manzdf., 1953, 29, 363, 418WILSON CLASSICAL ORGANIC ANALYSIS. 355formamide, by solution in acid followed by any of the usual titrimetricprocedures.282 Vanadium@) can be reduced quantitatively to vanadium(1v)by citric acid, which at the same time complexes any copper present.283The vanadium(1v) can then be determined by titration with standardiodine. Standard titrimetric methods for vanadium in carbon and low-alloysteels 284 and in ferro-vanadium 285 have been published.Indicators and Related Topics.-The indicator properties of some phos-phorus and arsenic analogues of methyl-orange, ethyl-orange, and Congo-redhave been studied.286 A new universal indicator has been proposed.2s7For a wide variety of titrations 4-amino-4’-methoxydiphenylamine has beenrecommended as a reversible redox indicator.288 The substance is watersoluble; at pH 0 the redox potential is 0.690 volt, and at pH 6 it is 0.375 volt.Linear starch fraction dissolved in 10% acetic acid is stated to be stableand sensitive.289 Sulphonic acid blue B has been proposed as an adsorptionindicator for iodide titrations in strongly alkaline media.290 Reviews ofthe use of fluorescent indicators for acid-base titrations, and recommendedexamples, have been publi~hed.2~~3 292Siloxene has been applied as a chemiluminescent indicator in the chromatetitration of lead solutions.2g3A new and simplified approach to the theory of pH, particularly in itsapplications to analytical chemistry, has been discussed.294 The pH ofphosphate and citrate buffers when calcium ions are added has been shownto be markedly affected because of the formation of association products.2956.CLASSICAL ORGANIC ANALYSIS.General.-The present state and future development of spot-test analysisas applied to organic analysis for the identification of functional groups andcompounds has been discussed.lMethods of control necessary in the determination of melting point bymeans of the Kofler hot stage have been described.296 A.J. Llacer 297 hasdevised a semimicro-pycnometer with a content of 2.5 ml. which can beused in conjunction with a good analytical balance. A method for thedetermination of the molecular weights of aromatic hydrocarbons throughformation and analysis of the picrates has been proposed.298 Methods havebeen described for the isopiestic determination of molecular weights upon3-7 mg. samples 299 and 1 mg. samples.3002s2 A. Musil, E. Gagliardi, and K. Reischl, 2. anal. Chew., 1962-1953, 137, 252.z83 M. R. Verma, V. M. Bhuchar, and V. P. Singh, J . Sci. I n d . Hes., India, 1953, 12,z S 6 G. M. Kosolapoif and G. G. Priest, J . Amer. Cltem. SOC., 1953, 75, 4847.Z S 7 T. Kato, K. Yamane, and 2. Hagiwara, Tech. Rep. TGhokzt Univ., 1953, 17, 148.288 L.Erdey and A. Bodor, 2. anal. Chem., 1952-1953, 137, 410289 J. L. Lambert, Analyt. Chem., 1953, 25, 984.291 M. Heros, Ann. Chim. analyt., 1953, 35, 114.292 J. De Rlent, J . Chem. Educ., 1953, 30, 145.2Q3 F. Kenny and R. B. Kurtz, Analyt. Chem., 1953, 25, 1550.394 F. L. Hahn, Analyt. Chim. Acta, 1953, 8, 297; J. Eeckhout, ibid., 9, 197.295 C. W. Davies and B. E. Hoyle, J . , 1953, 4134.296 0. Rizzolli, Mikrochim. Acta, 1953, 401.297 Mikrochem. Mikrochim. Acta, 1952-1953, 40, 179. 298 F. Scheibl, ibid., p. 343.2y9 J. E. Morton, A. D. Campbell, and T. S. Ma, Analyst, 1953, 78, 722.SO0 C. J. van Nieu.vyenburg and J. W. L. van Ligten, Analyt. Chim. Acta, 1953, 9, 66.B, 227. 284 B.S.I. Specif., 1952, 1121, Pt. 27. 285 Ibid., Pt.25.G. Mannelli and M. L. Rossi, Analyt. Chim. Acta, 1953, 9, 44356 ANALYTICAL. CHEMISTRY.Qualitative.-Existing methods for the detection of oxygen in organiccompounds have been examined, and a new method based on thermaldecomposition of the sample in a platinum contact in a stream of nitrogen,with detection of the resulting carbon monoxide, has been proposed.301Alkylene dihalides may be identified by reaction with 2-mercapto-6-nitro-ben~othiazole.~~~ Characteristic colours are produced in the reactionsbetween aliphatic alcohols and certain hydroxyaldehydes in the presenceof sulphuric acid.303 Glycols and their derivatives can be identified throughthe physical constants of the glycols together with the physical constants oftheir pseudo-saccharin ethers.304 The esters of phenols can be distinguishedfrom those of acids through the solubility of the potassium salts of thephenols in absolute methanoL305 A critical examination has been made ofthe 2 : 4-dinitrophenylhydrazones of carbonyl compounds in order to reachan explanation of some of the discrepancies in the literature regarding thesecompounds.306 Met hoxy- and ethoxy-carbonylhydrazones have been pro-posed as suitable for the identification of carbonyl compounds.307 Conden-sation of 1 : 4-diketones with p-nitroaniline gives derivatives which arepreferable for identification purposes to o x i m e ~ .~ ~ ~ Sugars give a specificcolour reaction with aminoguanidine followed by dichromate-sulphuric acidsolution.309 The eutectic fusion temperature and refractive index togetherare proposed as a means of identifying small amounts of arnin~-acids.~~O-~~~Alkaloids can be identified by determining the melting-points of theirprecipitates with sodium tetraphenylboron or with nitro-compounds, and ofthe eutectics with two or three standard substances.313Quantitative.-Recent developments in quantitative organic micro-analysis have been comprehensively re~iewed.~l4High-temperature furnaces prepared with an aluminium-chromium-cobalt wire winding have been worked up to 1250", and for short periods ateven higher temperatures.315 Specifications have been drawn up forcombustion boats and related apparatus.316G.F. Smith317 has made an investigation of the wet ashing of organicmaterial with perchloric acid, and has described conditions for carrying thisout with complete safety.By this method carbonaceous material is quantit-atively converted into carbon dioxide, but phosphorus, sulphur, and mineralconstituents are completely retained.W. Kirsten recommends polytetrafluoroethyIene joint links betweencombustion tube and absorption tube in the carbon and hydrogen deter-301 J. Goerdeler and €€, Domgorgen, Mikrochem. Mikrocieirn. Acta, 1952-1953,40,212.302 H. B. Cutter and A. Kreuchunas, Analyt. Chem., 1953, 25, 198.303 L. Rosenthaler and G. Vegezzi, Mitt. Lebensmitt.- Untersuch. Hyg., 1952, 43, 370.304 H. Bohme and H. Opfer, 2. anal. Chem., 1953, 139, 255.305 G. Carbone, J . Chem. Educ., 1953, 30, 315.306 L. I. Braddock, K.Y . Garlow, L. I. Grim, A. F. Kirkpatrick, S. W. Pease, A. J.Pollard, E. F. Price, T. L. Reissmann, H. A. Rose, and M. L. Willard, Analyt. Chern.,1953, 25,301. 307 N.Rabjohn and H. D. Barnstorff, J . Amer. Chem. SOC., 1963, 75,2259.308 M. Fetizon and P. Baranger, Compt. rend., 1953, 236, 1428.309 H. Tauber, Analyt. Chem., 1953, 25, 826.310 A. Lacourt, G. Sommereyns, C. Francotte, and N. Delande, Nature, 1953,172,906.311 Idem, Mikrochim. Acta, 1953, 306.313 R. Fischer and M. S. Karawia, ibid., p. 366.514 W. Kirsten, Analyt. Chem., 1953, 25, 74; R. Ldvy, Bull. SOC. chim., 1952, 19, 672.315 W. Kirsten, Analyt. Chem., 1953, 25, 805.316 B.S.I. Specif., 1953, No. 1428, Pt. I, 1. 317 Analyt. Cbim. Acta, 1953, 8, 397.312 G. Sommereyns, ibid., p.332WILSON : CLASSICAL ORGANIC ANALYSIS. 357minati0n.3~~ Apparatus has been described for the automatic micro-determination of carbon and hydrogen according to the Pregl-Zimmermanmethod but with use of manganese dioxide instead of lead dioxide.319The methods proposed for the direct determination of oxygen have beenexamined by an inter-laboratory panel, and four modifications of the Unter-zaucher procedure have been found to give results of reasonable accuracy,a11 of these methods taking pains to avoid the effect of pyrolytic hydrogen onthe iodine pent~xide.~*O E. G. Adams and N. T. Simmons report 321 thatthe iodine pentoxide used in the direct determination of oxygen must be asfree as possible from potassium, which lowers the reactivity.A semi-micro-method for the determination of oxygen is based on carbon reductionand determination of the carbon dioxide produced.322The Dumas-Pregl and Kjeldahl methods for determining nitrogen havebeen compared experiment ally.323 A modified all-glass apparatus forKjeldahl nitrogen in which digestion and distillation are carried out in asingle flask has been described.324 C. H. Perrin325 has advocated the useof sulphuric acid-mercuric oxide-pot assium sulphate for the digestion.P. R. W. Baker 326 has examined the effect of addition of selenium in sealed-tube digestions, and has found that it lowers the temperature of decom-position of ammonia by about 50". Reduction has been suggested as thelogical means of decomposing nitrogenous compounds before the Kj eldahldetermination of the nitrogen.M. Marzadro 327 has examined the selectiveeffect of the Kjeldahl method as applied to different types of nitrogen com-pounds, particularly heterocyclics. Investigation of the reactions takingplace in the Dumas determination of nitrogen have led W. Kirsten328 todevise a method depending on the conversion of carbon and carbon dioxideinto carbon monoxide and cornbustion of this with nickel oxide a t 1000".Conditions for application of the rapid combustion method to the deter-mination of nitrogen have been described.329The micro-Grote apparatus for the determination of halogens and sulphurhas been ~tandardised.~~~ A rapid combustion method 331 and an automaticcombustion method332 for these elements have been described.G. In-gram 333 has published data regarding the behaviour of manganese dioxidetowards nitrogen oxides with special reference to compounds containingchlorine and sulphur. W. Kirsten 334 recommends that in the determinationof halogens by dry combustion, the combustion products and the oxygenshould be allowed to react with hydrogen, forming water, which gives betterabsorption of the halogens as hydrides. The Zacherl-Krainick apparatus 335for the alkalimetric determination of halogen has been modified to deal with318 Mikrochirn. Acta, 1953, 41.3l9 R. L6vy and B. Cousin, Bull. SOC. chiwz., 1952, 19, 728.320 W. H. Jones, Analyt. Chew., 1953, 25, 1449.322 R. D. Hinkel and R. Raymond, Analyt. Chem., 1953, 25, 470.323 A. Konovalov, Ind.Chim. belg., 1953, 18, 339.324 F. J. Scandrett, Analyst, 1953, 78, 734.326 Analyst, 1953, 78, 500.328 Ibid., p. 121.330 B.S.I. Specif., 1953, No. 1428, Pt. A 4.331 P. Gouverneur and H. van Dijk, Annlyt. Chim. Acta, 1953, 9, 59.332 T. T. W'hite, C. J. Penther, P. C. Tait, and F. R. Brooks, Analyt. Chew., 1953, 25,334 Mikrochern. Mikrochim. Acta, 1952-1 953, 40, 170.335 31. K. Zacherl and H. G. Krainick, Mikrochem., 1932, 11, 61.321 Nature, 1953, 172, 1104.325 Analyt. Chem., 1953, 25, 968.327 Mikrochem. Mikvochim. Acta, 1952-1953, 40, 359.329 G. Ingram, Mikrochim. Acta, 1953, 131.1664. 333 Mikrochim. Acta, 1953, 71358 ANALYTICAL CHEMISTRY.compounds which also contain nitrogen and Modified methodsfor determination of chlorine and bromine by sodium fusion336 and bypotassium-silver dichromate digestion 337 have been described.Organiciodine can be converted by potassium chlorate-perchloric acid into iodate,which is then determined by standard methods.33s Compounds containingfluorine are decomposed in a specially designed bomb with sodium or potas-s i ~ m , ~ ~ ~ and the fluorine is titrated with thorium nitrate and a standardcomparison technique. Organic sulphur may be converted into benzidinesulphate and determined titrimetri~ally.~~~ In compounds containingnitrogen in addition to sulphur, combustion, precipitation of the stllphate by4-amino-4’-chlorodipheiiyl and subsequent alkalimetric titration, avoidsinterference from nitrogen and halogen.341Methods for determining silicon, bound in various ways, in organiccompounds, have been described.342 Phosphorus can be converted into thephosphovanadomolybdate.343 Antimony can be determined in compoundscontaining nitrogen and chlorine by wet digestion, solution in hydrogenbromide-bromine, reduction and precipitation as sulphide or titrimetricdetermination with standard b r ~ m a t e .~ ~ ~ Selenium compounds are decom-posed with sodium peroxide to selenate, which liberates 6 equivalents ofiodine for each selenium atom.344 Tellurium compounds are digested inperchloric acid, excess of standard dichromate is added, and the excess isdetermined with ferrous solution sodium diphenylaminesulphonate beingused as indicator.345The determination of weak acids by titration to the phenolphthaleinend-point has been examined 346 with special reference to the determinationof carboxyl, acetyl, benzoyl, or C-methyl groups.The titration must becarried out in cold solution, as the end-point in warm solution is unsatis-factory. Carbonyl compounds can be determined either by precipitation assemicarbazones and titration with iodate or by titration with hydroxylamine,a special bromophenol-blue indicator matching technique beingThey can also be determined 348 by addition of a measured excess of 2 : 4-dinitrophenylhydrazine, the excess being reduced by titanous chloride, andthe unchanged titanium(II1) being determined by titration with iron(II1).Twelve equivalents of titanous chloride are required for one molecule of thedinitro-compound.A method for the sernimicro-determination of thebenzoyl group has been des~ribed.3~~ Primary amines can be determinedgasometrically by liberation of nitrogen with nitrous acid.350 In suitable3350 D. S. Rao and G. D. Shah, Mikrochem. Mikrochim. Acta, 1962-1053, 40, 254.336 L. J. Lohr, T. E. Bonstein, and L. J. Frauenfelder, Analyt. Chem., 1953, 25, 1115.337 J. A. C. van Pinxteren, Phnrm. WeekbEad, 1953, 88, 489.338 B. Zak and A. J. Boyle, J . Amer. Pharm. Assoc., 1952, 41, 260.339 R. Belcher, E. F. Caldas, S. J . Clark, and A. Macdonald, Mikroclzim. Acta, 1953,341 R. Belcher, A. J. Nutten, and W. I. Stephen, Mikrochim. Acta, 1953, 51.342 R. Nagel and H. W. Post, J . Org. Chewz., 1952, 17, 1379.343 T. S. Ma and J. D. McKinley, Mikrochim.Acta, 1953, 4.343a N. T. Wilkinson, Analyst, 1953, 78, 165.344 G. Kainz and A. Resch, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 332.345 F. H. Kruse, R. W. Sanftner, and J. F. Suttle. Analyt. Chem., 1953, 25, 500.346 H. Jerie, Mikrochena. Mikrochim. Acta, 1952-1953, 40, 189.347 A. J. Fevell and J . H. Skellon, Analyst, 1953, 78, 135.348 W. Schoniger, H. Lieb, and K. Gassner, Mikrochim. Acta, 1953, 434.34s E. von Schivizhoffen and H. Danz, 2. anal. Chem., 1953, 139, 81.350 G. Kainz, Mikrochiwz. Acta, 1953, 349.283. 340 M. Chambon and H. Guyot, Ann. Plzarm. franc., 1952, 20, 685WILSON : INSTRUMENTAL METHODS. 359solvents primary, secondary, and tertiary amines can be differentiated bypotentiometric or indicator tit ration^.^^^ The reaction between titanouschloride and nitrobenzene has been examined.352 Errors in the usualmethod for the determination of N-methyl groups have been d i s c u ~ s e d .~ ~A thermometric and a conductometric method for determination of diazo-compounds have been described.354tartaricq ~ i n o l i n e . ~ ~ ~permanganate 361 and with copper(II1) periodate 362 have been investigated.Methods have been proposed for the determination of formicformaldehyde,367 methanol,358 organic ~ u l p h i d e s , ~ ~ ~ andThe reactions taking place in oxidations of organic compounds with7. INSTRUMENTAL METHODS.Electroana1ysis.-Electrochemical deposition methods in metallurgicalanalysis have been reviewed.363 A portable electroanalyser 364 and mercury-cathode cells 3 ~ ~ 6 9 have been described. Copper has been determined byusing an isolated anode to prevent slowing down of the determination throughre-oxidation of cuprous ion at the anode.370 Apparatus for the automaticcontrol of cathode potential has been described,371 and controlled-potentialanalysis has been applied t o the determination of zinc in brass.372 Copper,lead, and tin have been analysed in mixtures by deposition of copper andthen lead on the cathode, the tin being complexed to prevent deposition.373Silver, copper, and cadmium have been determined in mixtures.374 Theferric-ferrous system has been used to control cathode potential in thedeposition of ~ilver.37~ Bismuth, copper, and lead have been determinedin mixtures.37c Although apparently not yet utilised in electrodepositionanalysis, the effects of ultrasonic waves on electrode processes have beendescribed, and it has been pointed out that both the character of the depositand the composition, in the case of mixtures, may be altered, thus suggestingthat the effects of these waves might have some use in this field.377351 J. S.Fritz, Analyt. Chem., 1953, 25, 407.352 S. A. Newton, F. J. Stubbs, and Sir C. Hinshelwood, J., 1953, 3384.353 F. Franzen, W. Disse, and K. Eysell, Mikrochinz. Actu, 1953, 44.354 R. A. Paris and J. Vial, Ann. Chim. analyt., 1952, 34, 223.355 J. W. Hopton, Analyt. Chim. Acta, 1953, 8, 429.356 G. G. Rao and H. Sankegowda, Curr. Sci., 1952, 21, 188.357 J. I. de Jong, Rec. Trav. chim., 1953, 72, 356.358 D.A. Skoog and M. Budde, Analyt. Chem., 1953, 25, 822.359 W. H. Houff and R. D. Schuetz, ibid., p. 1258.360 D. Koszegi and E. SaIg6, 2. anal. Chenz., 1952, 136, 411.“ul A. Y . Drummond and W. A. Waters, .J., 1953, 435.302 G. Beck, Mikrochenz. Alikvoclzim. Acta, 1952-1953, 40, 258.363 T. S. West, Metallurgia, 1952, 46, 313.364 P. S. Farrington and R. L. Pecsok, J . Chew. Edzu., 1953, 30, 461.365 G. H. Aylward and H. V. Wooldridge, Analyst, 1953, 78, 386.366 V. A. Zarinsky, J . Anal. Chem., U.S.S.R., 1952, 7, 185.367 R. Bock and K.-G. Hackstein, 2. anal. Chew., 1953, 138, 339.368 R. B. Hahn, Analyt. Chew., 1953, 25, 1740.369 H. Coriou, J. HurC, and N. Meunier, Analyt. Chim. Acta, 1953, 9, 171.370 D. G. Foster, Analyt. Chew., 1953, 25, 1557.371 J.F. Palmer and A. I. Vogel, Amzlyst, 1953, 78, 428.372 D. G. Foster, Analyt. Chem., 1953, 25, 669.373 G. H. Aylward and A. Bryson, Analyst, 1953, 78, 651.374 R. W. C. Broadbank and €3. C. Winram, Metallurgia, 1953, 47, 155.375 G. Nonvitz, ibid., 48, 47.377 S. Barnartt, Quart. Reviews, 1953, 7, 84.376 Idem, ibid., 47, 157360 ANALYTICAL CHEMISTRY.Coulometry and Related Topics.-Coulometric titrations have beenreviewed critically and comprehensi~ely.~~~ A simple gas coulometer 379and apparatus for automatic coulometric titration 380 381 have been de-scribed. Because of the increased use of coulometric titrations, the coulombhas been suggested as the primary standard in all titrimetric processes inpreference to any chemical standard.382 I t has been shown that it is possibleto deduce correctly from polarographic investigations the conditions requiredfor obtaining optimum yields of coulometric reagent~3~3 Coulometrictitrations and back-titrations where oxidants and reductants are alternatelygenerated have been successfully carried out .384 Uranium has been deter-mined coulometrically by bromine 385 and by cerium(1v) .386 Thiosulphatehas been determined by electrically generated i0dine.~87 The coulometricdetermination of cadmium and zinc with stationary mercury-plated platinumelectrodes or, less satisfactorily, with amalgamated silver electrodes may beutilised in very dilute solution.388 Coulometric control has been applied tothe determination through electrodeposition of elements which normallydeposit together and therefore cannot be separated by controlled-potentialmethods.389 Thus in the deposition of chlorine and bromine on a silverelectrode two equations are obtained, one from the total number of coulombsrequired, which depends on the total number of equivalents deposited, andone from the total weight in grams of the deposit.The method is onlypossible if there is a considerable difference in the equivalent weights of thetwo elements.Polarography .-Polarographic instruments, technique, and literaturehave been extensively reviewed.390 The general theory of polarographicwaves391 and of irreversible waves 392 has been treated by several authors. Therising portion of reversible waves,393 the anomalous wave occurring after anormal wave in solutions of high ionic strength,394 and the influence of slow re-actions on the shape of the wave 395 have been studied. Simple 396 and photo-graphic-recording research 397 and cathode-ray 398 polarographs and a water-jacketed polarographic cell 366 have been described. J.Heyrovsky 399 hasapplied a polarographic oscilloscope to rapid qualitative analysis of ores, to378 P. S. TutundiiC, Autalyt. Chim. Actn, 1953, 8, 168.379 I. Berkes, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 160.380 W. N. Carson, Analyt. Chem., 1953, 25, 226.381 E. N. Wise, P. W. Gilles, and C. A. Reynolds, ibid., p. 1344.382 P. S. TutundEiC, Analyt. Chim. Acta, 1953, 8, 182.J. Badoz-Lambling, ibid., 1952, '4, 585.384 P. S. Farrington, D.J. Meier, and E. H. Swift, Analyt. Chern., 1953, 25, 591.385 W. N. Carson, ibid., p. 466.386 N. H. Furman, C. E. Bricker, and R. V. Dilts, ibid., p. 482.387 P. S. TutundiiC and S. MladenoviC, Analyt. Chim. Acta, 1953, 8, 184.388 K. W. Gardiner and L. B. Rogers, Analyt. Chem., 1953, 25, 1393.389 W. M. MacNevin, B. B. Baker, and R. D. McIver, ibid., p. 274.390 J. A. Lewis, Ind. Chem. Chem. Manuf., 1953, 29, 6, 58, 125, 172.391 P. Delahay, J . Amer. Chem. Soc., 1953, 75, 1430.392 P. Kivalo, K. B. Oldham, and H. A. Laitinen, ibid., 1953, '75, 4148; T. Berzinsand P. Delahay, ibid., p. 5716; P. Delahay, ibid., p. 1190.393 K. B. Oldham, P. Kivalo, and H. A. Laitinen, ibid., p. 5712.394 L. Meites, ibid., p. 3809.395 J. Badoz-Lambling and R.Gauguin, Analyt. Chim. Ada, 1953, 8, 471.396 €3. W. hlundy and N. W. Allen, J . Chem. Educ., 1953, 30, 143.397 F. J. Bryant and G. F. Reynolds, Analyst, 1953, '48, 373.398 G. F. Reynolds and H. M. Davis, ibid., p. 314.399 J. Heyrovsky, Analyt. Chim. Acta, 1953, 8, 283WILSON : INSTRUMENTAL METHODS. 361the detection of impurities in organic compounds, and to qualitative gasanalysis. Determinations have been carried out with rotating 400 and withstationary 401 mercury-plated platinum electrodes, a large stationary poolof mercury being used instead of a dropping-mercury cath0de.~02 Theanalysis of flowing samples, with use of automatic control, has been investig-ated.403* 404 The polarograph has been applied to the estimation of currentefficiency of coulometric proces~es,~~~y 405 and to the continuous determinationof ions discharged from a chromatographic column.406 Studies have beenmade of polarographic behaviour in concentratedcalcium chloride solutions 407and in acetate solutions.408 The application of polarography to the examin-ation of the nature of complexed cations has been discussed.4osPolarographic methods have been described for the determination ofnitrite,410 nitrate,411,412 mixtures of hydrogen peroxide with organic per-o x i d e ~ , ~ ~ ~ , 414 tellurium,415 germaniumI4l6 and alkali metals and alkaline-earth metals.4l7 Calcium has been determined indirectly by precipitationwith chloranilic acid.418 Methods have been proposed for zinc 419 andc0pper.41~9 420 Aluminium has been determined indirectly by measurementof the reduction of the polarographic wave by ethylenediaminetetra-acetica ~ i d .~ 2 l Methods have been described for indium,422 ir0n,~2~chromi~m,~23 molybdenum,425 lead,426 titanium,427 ~ i r c o n i u m , ~ ~ ~ ~ 429 andosmium.430 Polarography has been suggested as a means of determiningacid anhydrides.431Amperometric Titrations-The best conditions for amperometric deter-minations at const ant voltage can be established by polarographic investig-400 W. D. Cooke, Analyt. Chem., 1953, 25, 215.401 T. L. Marple and L. B. Rogers, ibid., p. 1351.402 C. A. Streuli and W. D. Cooke, ibid., p. 1691.403 L. D. Wilson and R. J. Smith, ibid., p. 218.405 R. N. Adams, C. N. Reilley, and N. H. Furman, ibid., p.1160.406 W. Kemula, Roczn. Chem., 1952, 26, 281.407 G. F. Reynolds, H. I. Shalgosky, and T. J. Webber, Analyt. Chim. Acta, 1953, 8,408 M. A. DeSesa, D. N. Hume, A. C. Glamm, and D. D. DeFord, Analyt. Chem., 1953,409 K. H. Gayer, A. Demmler, and M. J. Elkind, J . Chem. Educ., 1953, 30, 557.410 D. T. Chow and R. J. Robinson, Analyt. Chem., 1953. 25. 1493.411 M. C. Rand and H. Heukelekian, ibid., p. 878.412 W. A. Lawrance and R. M. Briggs, ibid., p. 965.*13 H. Bruschweiler, G. J. Minkoff, and K. C. Salooja, Nature, 1953, 172, 909.414 W. M. MacNevin and P. F. Urone, Analyt. Chem., 1953, 25, 1760.415 E. Norton, R. W. Stoenner, and A. I. Medalia, J . Amer. Chem. Soc., 1953, 75, 1827.416 D. A. Everest, J., 1953, 660; A. K. Das Gupta and C.K. N. Nair, Analyt. Chim.417 M. Shinagawa, J . Sci. Hiroshima Univ.. 1952, 16, 145.418 B. Breyer and J. McPhillips, Nature, 1953, 172, 257; Analyst, 1953, 78, 666.419 G. B. Jones, Analyt. Chim. Acta, 1952, 7, 578.420 D. M. Hubbard and E. C. Spettel, Analyt. Chem., 1953, 25, 1245.421 D. Lydersen, 2. anal. Chem., 1953, 139, 401.422 M. Maraghini, Ann. Chim. appl., 1951, 41, 776.423 M. Perkins and G. F. Reynolds, Analyst, 1953, 78, 480.424 E. C. Mills and S. E. Hermon, Metallurgia, 1952, 46, 259, 266.425 L. Meites, Analyt. Chem., 1953, 25, 1752.4 2 6 I. M. Kolthoff, J. Jordan, and A. Heyndrickx, ibid., p. 884.427 R. P. Graham. A. Hitchen, and J. A. Maxwell, Canadian J . Chem., 1952, 30, 661.428 E. L. Colichman and W. H. Ludewig, Analyt. Chem., 1953, 25, 1909.429 R.P. Graham, E. VanDalen, and A. M. C. Upton, Canadian J . Chem., 1952, 30.431 C, Ricciuti, C. 0. Willits, H. B. Knight, and D. Swern, ibid., p. 933.404 Idem, ibid., p. 334.558, 564; 9, 91.25, 983.Acta, 1953, 9, 287.1069. 430 I. M. Kolthoff and E. P. Parry, Analyt. Chem., 1953, 25, 188362 ANALYTICAL CHEMISTRY.ation, and a relation can be derived between amperometric and potentio-metric tit ration^.^^^ Amperometric titration methods have been applied inthe determination of ammonia,433 ~ u l p h a m a t e s , ~ ~ ~ i0dine,~3~-~37thorium,439 and organic sulph~r.~~OPotentiometric Titrations.-The polarisation curve of an oxidation-reduction system has been discussed in relation to the dead-stop end-pointmethod of t i t r a t i ~ n .~ ~ ~ An electrometer for use in small-scale potentiometrictit ration^,^^^ apparatus for the dead-stop method which gives audible warningof the end-point 443 or gives a readily variable warning of the approach ofthe e n d - p ~ i n t , ~ ~ ~ a cell for potentiometric titrations in an inert atmosphere,366a micro-glass electrode,445 jacketed vessels for glass electrodes,446 and silverreference electrodes 4 4 7 9 448 have been described. S. Samson 449 has describeda method for the determination of chloride which uses two silver electrcdesa t a small potential difference; the current flowing between these is measuredby a sensitive galvanometer, and at the end-point the change in the electrodeprocesses cause a sharp break in the curve.Potentiometric titration methods have been proposed for boron in nickelb ~ r i d e , ~ ~ ~ and for tellurium,451 zinc,452 iron,453 titanium in the presence of~ a n a d i u m , ~ 5 ~ microgram amounts of fattyConductance Methods.-The principles of high-frequency conducto-metric titrations have been discussed.458 Causes of the difference between theconductometric and the true end-point in the titration of sulphate havebeen examined.459 Conductometric titration has been proposed for thedetermination of the concentration of sulphuric acid 460 and for the estimationof potassium 461 and ofColorimetry and Absorptiometry-Modern applications of the spectro-photometer in the ultra-violet and the visible region to analytical problemshave been reviewed.463 A collection of methods for use with the Lovibondand aldehydes.456> 457432 R.Gauguin and G. Charlot, Analyt. Chim. Acta, 1953, 8, 65.433 I. M. Kolthoff, W. Stricks, and L. Morren, Analyst, 1953, 78, 405.434 S. T. Hirozawa and R. C. Brasted, Analyt. Chem., 1953, 25, 221.435 G. Knowles and G. F. Lowden, Analyst, 1953, 78, 159.4a8 H. P. Kramer, W. A. Moore, and D. G. Ballinger, Analyt. Chenz., 1952, 24, 1892.437 I. M. Kolthoff and J. Jordan, ibid., 1953, 25, 1833.438 V. M. Peshkova and 2. A. Gallay, J . Anal. Chem., U.S.S.R., 1952, 7, 152.439 L. Gordon and C. R. Stine, Analyi!. Chem., 1953, 25, 192.440 C. L. Rulfs and A. A. Mackela, ibid., p. 660.441 G. Duyckaerts, Analyt. Chim. Acta, 1953, 8, 57.442 D. M. W. Anderson and C. T. Greenwood, Chem. and Ind., 1953, 476.443 H.A. Glastonbury, Analyst, 1953, 78, 682.444 R. E. Collier and D. J. Fricker, ibid., p. 440.445 E. F. Hartree, Biochem. J., 1952, 52, 619.446 S. Lewin, Chem. and Ind., 1953, 1193.448 R. A. Glenn, Analyt. Chem., 1953, 25, 1916.450 H. Blumenthal and W. Fall, Analyt. Chem., 1953, 25, 1120.451 I. M. Issa and S. A. Awad, Analyst, 1953, 78, 487.452 A. Mayer, G. Bradshaw, and J. Deutschman, ibid., 367.453 M. B. Schigol and N. B. Burchinskaya, J . Anal. Chem., U.S.S.R., 1952, 7, 289.454 M. C. Steele and F. M. Hall, Analyt. Chim. Acta, 1953, 9, 384.455 B. W. Grunbaum, F. L. Schaffer, and P. L. Kirk, Analyt. Chem., 1953, 25, 480.4 5 6 S. Siggia and E. Segal, ibid., p. 830.457 Idem, ibid., p. 640.459 D. Lydersen and 0.Gjems, 2. anal. Chem., 1952-1953, 137, 189.460 C. H. Wood, I n d . Chem. Chem. Manuf.., 1953, 29, 152.461 V. V. Udovenko and G. B. Pasovskaya, J . Anal. Chem., U.S.S.R., 1952, 7, 161.462 Idem, ibid., p. 158.447 E. Bishop, Analyst, 1953, 78, 149.440 Nature, 1953, 172, 1042.458 C. N. Reilley and W. H. McCurdy, ibid., p. 86.463 E. J. Stearns, Anslyt. Chenz., 1953, 25, 1004WILSON : INSTRUMENTAL METHODS. 363Comparator has been published.464 Numerous unexplained departures fromabsorptiometric theory in photoelectric determinations have been studied,and the conditions for ensuring the best performance of an instrument havebeen defined.465 The importance of testing the linearity of response ofphotoelectric instruments has been stressed.466 H.A. Liebhafsky and H. G.Pfeiffer467 recommend that Beer’s law should be redefined in terns ofabsorbing centres, since it is then applicable to the many cases in which theparticles of a suspended lake obey the law.R. H. Hamilton 4G8 has recommended the insertion of a glass plate in thesolution to be measured, transmittance being read before and after, in orderto produce the effect of adding a layer of solution of uniform thickness, thusavoiding the necessity for using matched tubes for determinations. Differ-ential colorimetry has been stated to give results of an accuracy comparablewith classical methods in certain analyses, even when used with relativelysimple photometers or in other cases where Beer’s law may not be valid.46gThe added importance of temperature effects in differential colorimetry hasbeen stressed.470 A simple spectrophotometer using an interference filter,471and a universal high-sensitivity photometer 472 have been described.Photometric methods have been recommended for the standardisationof potassium permanganate solutions 473 and for the complete analysis oflight all0ys.47~Methods have been proposed for the determination of chlorine witho-tolidine,475 NN-dimethyl-fi-phenylenediamine,475 barbituric andsilver thiocyanate ; 477 for fluorine with aluminium-h~matoxylin,47g~ 479with the thorium lakes of sodium alizarin~ulphonate,~~~ chrome-azurolS 481 or N-(4-o-arsenophenylazo-l-naphthyl)ethylenediamine ; 482 for ammoniawith sodium phenoxide-hypochlorite 483 or pyridine with bis-(3-methyl-l-phenyl-5-pyrazolone) 4g4 which can also be used for cyanate; for hydroxyl-amine with 8-hydroxyquinoline ; 485 for nitrite with Paminobenzenesulphonicacid ; 4g6 for phosphorus as molybdenum-blue ; 487-491 for arsenic as molyb-464 “ Handbook of Colorimetric Chemical Analytical Methods for Industrial, Re-search and Clinical Laboratories,” Salisbury, 1953.4 6 5 L.S. Goldring, R. C. Hawes, G. H. Hare, A. 0. Beckman, and M. E. Stickney,Analyt. Chein., 1963, 25, 869. 4 6 6 C. G. Cannon and I. S. C. Butterworth, ibid., p. 168.467 J . Chem. Educ., 1953, 30, 450.469 A. Ringbom and K. bterholm, ibid., p. 1798. 470 R. Bastian, ibid., p. 259.471 H. W. Safford and D. F. Westneat, J . Chem. Educ., 1953, 30, 343472 G. Oster, Analyt.Chem., 1953, 25, 1165.473 J . E. Ransford, J . Chem. Educ., 1953, 30, 350.4 7 4 M. Jean, Analyt. Chiwz. Acta, 1952, 7, 523.4 7 5 G. Lipps and P. Gaertner, 2. anal. Chem., 1953, 139, 188.476 E. Asmus and H. Garschagen, ibid., 138, 404.4 7 7 A. Bezerra Coutinho and M. Dulce Almeida, Anal. Assoc. qudm., Brasil, 1951,10, 83.478 J. S. Beveridge, G. J. Hunter, and B. J. MacNulty, Analyt. Chim. Acta, 1953, 9.480 J. M. Icken and B. M. Blank, Analyt. Chem., 1953, 25, 1741.481 D. Revinson and J. H. Harley, ibid., p. 794.482 H. F. Liddell, Analyst, 1953, 78, 494.483 J. P. Riley, d n a l y t . Chim. Acta, 1953, 0, 575.484 J. M. Kruse and M. G. Mellon, Analyt. Chem., 1953, 25, 1188.4 q 5 W. Prodinger and 0. Svoboda, Mikrochim. Acta, 1953, 426.486 J.M. Pappenhagen and M. G. Mellon, Analyt. Chem., 1963, 25, 341.487 F. L. Schaffer, J. Fong, and P. L. Kirk, ibid., p. 343.488 R. A. Chalmers, Aaalyst, 1953, 78, 32.491 A. Gee and V. R. Deitz, Analyt. Chem., 1953, 25, 1320,468 Analyt. Chem., 1953, 25, 399.330. 479 G. J. Hunter, B. J. MacNulty, and E. -4. Terry, ibid., 8, 361.H. W. Harvey, ibid., p. 110. 490 H. K. Lutwak, ibid., p. 661364 ANALYTICAL CHEMISTRY.denum-blue 492 or as arsenovanadoniolybdic acid ; 493 for oxygen in tin byamalgamation of the tin and determination as molybdenum-blue ; 494 forsulphur as bismuth ~ u l p h i d e , ~ ~ ~ as zinc sulphide and conversion intomethylene-bl~e,~~~ by molybdenum-blue 497 or with p-phenylenediamine ; 498for selenium and tellurium by solution in concentrated sulphuric acid; 499for tellurium as a red hydrosol ; 500 for carbon in titanium by nitration; 501for cyanide and thiocyanate with barbituric acid; 502 for cyanide with bis-(3-methyl-l-phenyl-5-pyrazolone) and pyridine ; 503 for thiocyanate with acopper-pyridine reagent ; 503 for boron with curcumin 504 or quinalizarin ; 505for silicon by molybdenum-blue.506, 507 The silicomolybdate colorimetricdetermination has been examined for a wide range of silicon : sodium ratios.508Potassium has been estimated through the cobaltinitrite as cobalt8-hydroxyquinoline complex 509 or by dipicrylamine ; 510 czsium throughthe cobaltinitrite and the Griess reaction; 511 calcium as the murexide513 through oxalate by the decrease in the colour of the ferricsalicylate complex,514 through the molybdate by conversion into molybdenumthiocyanate 515 or by oxalohydroxamic acid ; 516 magnesium with Solochrome-black ; 5179 518 zinc by Rh~damine-B,~~~ by di-2-naphthylthiocarbazone 520or by #-dimethylaminoazophenylarsinic acid ; 474 cadmium by dithizone 521or +-nitrodiazoaminoazobenzene (cadion) ; 522 mercury by 2 : 6-dimet hyl-hept-5-en-2-01; 523 copper by diethyldithio~arbamate,~~~9 525 by diethyl-ammonium dieth~ldithiocarbamate,~2~ 1 : lo-phenanthr~line,~~~ 2 : 9-di-methyl-4 : 7-diphenyl-1 : lO-phenanthr~line,~*~ 2 : 2'-dip~ridyl,~~~ 2 : 2'-di-493 H.Onishi and E. B. Sandell, Mikrochim. Acta, 1953, 34.4 ~ 1 3 D. K. Gullstrom and M. G. Mellon, Analyt. Chem., 1953, 25, 1809.494 L. Silverman and W.Gossen, Analyt. Chim. Acta, 1953, 8, 436.d g 5 H. Koren and W. Gierlinger, Mikrochim. Acta, 1953, 220.496 W. Sonnenschein and K. Schafer. 2. anal. Chem., 1953, 139, 15.497 P. 0. Bethge, Svensk Kem. Tidskr.. 1952, 64, 177.498 S. Musha, Sci. Rep. Res. Inst. T6hoku Univ., 1953, 5, A , 232.499 S. E. Wiberley, L. G. Bassett, A. M. Burrill, and H. Lyng, Analyt. Chem., 1953,501 G. Norwitz and 0. W. Simmons, Analyt. Chim. Acta, 1953, 9, 555.502 E. Asmus and H. Garschagen, 2. anal. Chem., 1953, 138, 414.503 J. M. Kruse and M. G. Mellon, Analyt. Chem., 1953, 25, 446.504 L. Silverman and K. Trego, ibid., p. 1264.5 0 5 B. A. Ripley-Duggan, Analyst, 1953, 78, 183.506 0. A. Kenyon and H. A. Bewick, Analyt. Chem., 1953, 25, 145.507 C. L. Luke, ibid., p.148.509 S. Baar, Analyst, 1953, 78, 353.510 R. Faber and T. P. Dirkse, Artalyt. Chem., 1953, 25, 808.511 C. Duval and M. Doan, Mikrochim. Ada, 1953, 200.612 L.-E. Tammelin and S . Mogensen, Acta Chem. Scand., 1952, 6, 988.513 11. B. Williams and J. H. Moser, AnaZyt. Chem., 1953, 25, 1414.514 F. Burriel Marti, J. Ramirez Mufioz, and E. Perndndez Caldas, ibid., p. 583.515 G. E. Harrison and W. H. A. Raymond, Analyst, 1953, 78, 528.516 S. K. Dhar and A. K. Das Gupta, J . Sci. I n d . Res., India, 1952, 11, B, 520.517 W. Discherl and H. Breuer, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 322.518 A. E. Harvey, J. M. Komarmy, and G. M. Wyatt, Artalyt. Chem., 1953, 25, 498.519 G. Martin, Bull. SOC. Chim. Ciol., 1952, 34, 1174.520 A.E. Martin,Analyt. Chem., 1953. 25, 1853.522 E. Fisher, B. T. Estes, and J. E. Rose, Analyst, 1953, 78, 729.523 A. G. Brook, A. Rodgman, and G. F. Wright, J . Org. Chem., 1952, 17, 988.524 J. K. Livingstone and N. D. Lawson, Analyt. Chem., 1953, 25, 1917.525 J. M. Chilton, ibid., p. 1274.527 D. H. Wilkins and G. F. Smith, Analyt. Chim. Acta, 1953, 9, 538.528 Idem, Analyt. Chem., 1953, 25, 510.529 J. P. Mehlig and P. L. Koehmstedt, ibid., p. 1920.25, 1586. 500 R. A. Johnson, ibid., p. 1013.508 D. T. Chow and R. J. Robinson, ibid., p. 646.52L B. E. Saltzman, ibid., p. 493.526 P. F. Wyatt, Analyst, 1953, 78, 656WILSON : INSTRUMENTAL METHODS. 365quinolyl,s*, 530,531 N’-phenylsemicarbazide 532 or triphenylmethylarsoniumthiocyanate ; 533 silver by fJ-dimethylaminobenzylidenerhodanine ; 534 alu-minium in thorium by 8-hydroxyquinoline, thorium being masked by 4-sulphobenzenearsonic acid 535 or by or-picolinic acid ; 536, 537 cerium by ultra-violet photometry of a ceric-carbonate complex; 538 thallium as the halidecomplex, preferably the cldoro-one ; 539 manganese by diethylammoniumdiethyldithiocarbamate ; 526 rhenium by extraction as tetraphenylarsoniumper-rhenate and conversion into rhenium thiocyanate ; 540 iron as c h l ~ r o - , ~ ~ sulphat0-,~42 or oxalato-complexes,543 by t h i ~ c y a n a t e , ~ ~ ~ , 54s by 8-hydroxy-quinoline,546 by nitroso-R salt ,547 by photometric titration with ceric solu-tion, 548 by 1 : lO-phenanthr~line,~~~ by various alkylamino-phenanthrolines, 549by 4 : 7-diphenyl-1 : lO-phenanthr~line,~~~ by 2 : 6-bis-2’-pyridylpyridineand its alkyl derivatives,551 by thioglycollic by 5 : 6-benzoquin-aldinic by a-picolinic a ~ i d , 5 ~ ~ , 5549 555 by proto~atechualdehyde,~~~by c~pferron,52~ or by 5-3’-carboxy-2’-hydroxy-l’-methylazobenzene-4-sulphonic acid ; 149 cobalt by nitroso-R salt ,557-559 by 2-nitroso-l-naphthol, 560by t riphen ylmet hylarsonium t hiocyanat e, 561 as diet hyldithiocarbamate, 525or by 2 : 6-bis-2’-pyridylpyridine ; 551 nickel as the dimethylglyoximecomplex, 562 by 8-hydro~yquinoline,~~~ by sodium diethyldithiocarbamate 525or by p-mercaptopropionic acid; 563 chromium as dichromate 564 or bydiphenylcarbazide ; 565 molybdenum as molybdenum thiocyanate in thevisible 5660rin theultra-violet region,567 by3 : 4-dimercaptotoluene (dithiol),56s530 R.J. Guest, Analyt. Chem., 1953, 25. 1484.531 J. Hoste, J. Eeckhout, and J. Gillis, Analyt. Chiin. Acta, 1953, 9, 263.532 E. M. Skibina, J . Anal. Chem., U.S.S.R., 1952, 7, 244.533 K. W. Ellis and N. A. Gibson, Analyt. Chim. Acta, 1953, 9, 368.534 A. Ringbom and E. Linko, ibid., p. 80.535 D. W. Margerum, W. Sprain, and C. V. Banks, Analyt. Chem., 1953, 25, 249.536 A. K. Majumdar and B. Sen, Analyt. Chim. Acta, 1953, 8, 378.537 Idem, ibid., p. 384.539 C. Merritt, H. M. Hershenson, and L. B. Rogers, ibid., p. 572.540 J. M. Beeston and J. R. Lewis, ibid., p. 651.541 G. A. Gamlen and D. 0. Jordan, J., 1953, 1435.542 R. Bastian, R. Weberling, and F. Palilla, Analyt. Chem., 1953, 25, 284.543 M.Bobtelsky, D. Chasson, and S. F. Klein, Analyt. Chim. Acta, 1953, 8, 460.544 S. 2. Lewin and R. S. Wagner, J . Chem. Educ., 1953, 30, 445.545 J. E. Houlihan and P. E. L. Farina, Analyst, 1953, 78, 559.546 E. Sudo, Sci. Rep. lies. I n s t . TGhoku Univ., 1952, 4, 347.547 J. A. Dean and J. H. Lady, Analyt. Chem., 1953, 25, 947.548 C. E. Bricker and P. B. Sweetser, ibid., p. 764.548 D. H. Wilkins, W. H. McCurdy, and G. F. Smith, Analyt. Chinz. Acta, 1953, 8, 46.550 R. E. Peterson, Analyt. Chem., 1953, 25, 1337.551 D. H. Wilkins and G. F. Smith, Analyt. Chzm. Acta, 1953, 9, 338.552 D. L. Leussing and I. M. Kolthoff, J . Amer. Chem. SOC., 1953, 75, 3904.553 A. K. hlajumdar and B. Sen, Analyt. Chim. Acta, 1953, 9, 529.554 Idem, ibid., p.536.556 M. Y. Shapiro, J . Anal. Chem., U.S.S.R., 1952, 7, 214.557 F. Burriel Marti and R. Gallego, Anal. real Sot-esp. Fis. Quim., 1952,4$, B, 793,801.558 R. Gallego, W. B. Deijs, and J. H. Feldmeijer, Rec. Trav. chim., 1952, 71, 987.55Q J. N. Pascual, W. H. Shipman, and W. Simon, Analyt. Chena., 1953, 25, 1830.560 H. Almond, ibid., p. 166.j 6 1 K. W. Ellis and N. A. Gibson, Analyt. Chim. Acta, 1953, 9, 275.562 W. A. Forster, Analyst, 1953, 78, 560.563 J. B. Lear and M. G. Mellon, Analyt. Chew., 1953, 25, 1411.564 A. A. R. Wood, Analyst, 1953, 78, 54.5 6 5 G. Norwitz and M. Codell, Analyt. Chim. Acta, 1953, 9, 646.566 J. L. Grigg, Analyst, 1953, 78, 470.667 G. E. Markle and D. F. Boltz, Analyt. Chem., 1953, 25, 1261.5B8 S. H . Allen and 31.H. Hamilton, Analyt. China. Acta, 1952, 7, 483.538 G. Telep and D. F. Boltz, Analyt. Chem., 1953, 25, 971.5 5 5 Idem, ibid., 8, 369366 ANALYTICAL CHEMISTRY.mercaptoacetic acid,569 disodium 1 : 2-dihydroxybenzene-3 : 5-disulphonate(tiron) ; 570 tungsten with quin01,~~l d i t h i 0 1 , ~ ~ ~ or as phosphovanadotungsticacid ; 493 uranium by 8--hydroxyq~inoline,~~~~ 573 dibenzoylmethane 574 orphotometric titration with ceric solution; 548 tin with hzematoxylin 575 oras the complex silicotungstic-hexamethylenetetraminetin(1v) salt ; 474 leadas the chloro-complex 539 or by dithizone using reversion technique; 576titanium by sulphosalicylic acid 577 or chromotropic acid; 578 zirconium by2-(2-hydroxy-3 : 6-disulpho-l-naphthy1azo)benzenearsonic acid (thorin) 579or quercetin.580 The determination of thorium by 8-hydroxyquinolineabsorptiometrically seems unsatisfactory since two distinct complexes areformed.581 Thorium can be determined by thorin ; 5829 antimony as iodo-antimonous acid 584 or by rhodamine-B; 585 vanadium by S-hydroxy-q ~ i n o l i n e , ~ ~ ~ , 586 c~pferron,~8~ 1 : 10-phenanthroline ; 588 niobium in solutionin hydrochloric acid in the ultra-violet region,589 by the thiocyanate com-plex 590 or q u i n 0 1 . ~ ~ ~ Niobium and tantalum can both be determined asperoxy-compounds by measurement in the ultra-violet region. 591 Tantalumcan be determined by pyrogallol 592 or pyrogallic acid; 571 bismuth by thio-urea,474 phosphotungstic a ~ i d , ~ 7 ~ or as the chloro-complex in the ultra-violetregion.539 Colorimetric and photometric methods for determining theplatinum metals have been reviewed.593, 594 Osmium can be extracted asthe tetroxide and determined by thi0urea.5~~ Ruthenium can be determinedby the same reagent.596 Metallic palladium in a finely divided conditioncan be determined by phosphomolybdic acid and carbon monoxide. 597Photometric methods have been used to determine polynuclear aromatichydrocarbons, 598 aliphatic sulphides as iodine complexes in the ultra-violet,5g9 oxalate as the ferric oxalate complex 543 or by the decrease inoptical density of the ferric salicylate complex,514 amino-groups with diazo-569 F.Will and J. H. Yoe, Analyt. Chem., 1953, 25, 1363.5 7 0 Idem, Analyt. Chim. Acta, 1953, 8, 546.5 7 1 L.Ikenberry, J. L. Martin, and W. J. Boyer, Analyt. Chern., 1953, 25, 1340.5 7 2 0. Silverman, L. Moudy, and D. W. Hawley, ibid., p. 1369.573 B. Hok, Svensk Kem. Tidskr., 1953, 65, 106.574 J. H. Yoe, F. Will, and R. A. Black, Analyt. Chem., 1953, 25, 1200.5 7 5 H. Teicher and L. Gordon, ibid., p. 1182.5 7 6 H. M. Irving and E. J . Butler, Analyst, 1953, 78, 571.5 7 7 M. Ziegler and 0. Glemser, Z. anal. Chem., 1953, 139, 92.578 W. W. Brandt and A. E. Preiser, Analyt. Chem., 1953, 25, 567.5 7 9 A. D. Horton, ibid., p. 1331.580 F. S. Grimaldi and C. E. White, ibid., p. 1886.581 T. Moeller and M. M. V. Ramaniah, J . Amer. Chew. Soc., 1953, 75, 3946.582 C. V. Banks and C. H. Byrd, Analyt. Chem., 1953, 25, 416.583 C. V. Banks, D.W. Klingman, and C. H. Byrd, ibid., p. 992.584 A. Elkind, K. H. Gayer, and D. F. Boltz, ibid., p. 1744.585 C. L. Luke, ibid., p. 674.587 H. H. Willard, E. L. Martin, and R. Feltham, ibid., p. 1863.5 8 8 G. Jantsch and F. Zemek, Z . anal. Chegn., 1953, 139, 249.589 J. H. Kanzelmeyer and H. Freund, Analyt. Chewz., 1953, 25, 1807.590 G. Norwitz, M. Codell, and F. D. Verderame, Analyt. Chim. Acta, 1953, 9, 561.591 F. C. Palilla, N. Adler, and C. F. Hiskey, AnaZyt. Chenz., 1953, 25, 926.598 J. I. Dinnin, ibid., p. 1803.594 F. E. Beamish and W. A. E. MacBryde, Analyt. Chim. Acta, 1953, 9, 349.595 R. D. Sauerbrunn and E. B. Sandell, ibid., p. 86.596 A. Musil and R. Pietsch, 2. anal. Chem., 1952-1953, 137, 259.597 R. A. McAllister, Analyst, 1953, 78, 65.598 R.Schnurmann, W. F. Maddams, and &I. C. Barlow, Analyt. Chenz., 1953, 25,5 8 6 N. A. Talvitie, ibid., p. 604.693 G. H. Ayres, ibid., p. 1622.1010. 599 S . H. Hastings, ibid., p. 420WILSON INSTRUMENTAL METHODS. 367tised sulphanilic acid or by precipitation with 1 -fluoro-2 : 4-dinitrobenzeneand conversion into 2 : 4-dinitrophenyl derivative of the amine,601 pyridineby cyanogen bromide and barbituric acid,602 and sugars by benzidine 603 or3 : 4-dinitrobenzoic acid.604Nephe1ometry.-Sulphur can be determined nephelometrically by oxid-ation with nitric acid-hydrochloric acid-selenium to sulphate and conversionof this into barium ~ulphate.~O~ Glycol-ethanol-water mixtures have beenreported satisfactory for production of stable barium sulphate suspensions.606Selenium has been determined by reduction with ascorbic acid.607 Nephelo-metric determinations of calcium as oxalate,608 zinc as diethyldithiocarb-amate,603 tin by cupferron 474 or hydroxynitrophenylarsinic acid 610 havebeen reported. Nephelometric titration has been used for the determin-ation of calcium,611 aluminium, iron, and chromium 612 with phthalate; ofnickel with dimethylglyoxime ; 613 and of lead with Organicsubstances such as camphor, furfuraldehyde and isobutanol have been Lsedas indicators in the turbidimetric titration of aqueous solutions of salts, anda method of choosing a suitable indicator has been described.615Fluorimetry .-Fluorimetric methods of determination have been pro-posed for fluoride by the decrease of intensity of the fluorescence of di-hydroxyazo-dyes ; 616 for beryllium,617 aluminium,61s indium 619 as 8-hydr-oxyquinoline complexes ; and for uranium by fusion with sodium fluoride.620Emission Spectrography.-A method has been described for the rapidsemi-quantitative determination of 68 elements in one operation, by use ofstandard plates and visual comparison.621 Twenty-one common cationscan be identified with the spectroscope and a spark source, and the lowerlimits of identification for these have been determined.622 Chemical enrich-ment methods prior to spectrographic analysis of trace elements have beende~cribed.~23, 624 The spectrographic method has been applied to the deter-mination of trace elements in lubricating oils 625 and in zirconium andhafnium.626 A mode of procedure is described for determining residual6oo D.Fraser and H. G. Higgins, Nature, 1953, 172, 459.601 F. C. McIntire, L. M. Clements, and RI. Sproull, Analyt. Chem., 1953, 25, 1757.602 E. Asmus and H. Garschagen, 2. anal. Chem., 1953, 139, 81.603 J. I<. N. Jones and J . B. Pridham, Nature, 1953, 172, 161.1 3 ~ 4 E. Bore1 and H. Deuel, Helv. Chim. Acta, 1953, 36, 801.605 A. Steinbergs, Analyst, 1953, 78, 47.606 G. Toennies and B. Bakay, Analyt. Chem., 1953, 25, 160.b07 31. N. Rudra and S. Rudra, Curr. Sci., 1952, 21, 229.608 J . G. Hunter and A. Hall, Analyst, 1953, 78, 106.609 J . E. 0. Mayne and G. H. Noordhof, ibid., p. 625.610 AT. Jean, Analyt. Chim. Acta, 1953, 8, 432.611 M.Bobtelsky and I. Bar-Gadda, ibid., 9, 168.612 I d e m , ibid., p. 525.614 M. Bobtelsky and B. Graus, ibid., p. 163.615 A. I. Spiridonova, J . Appl. Chem., U.S.S.R., 1952, 25, 159.616 W. A. Powell and J. H. Saylor, Analyt. Chem., 1953, 25, 960.617 T. V. Toribara and K. E. Sherman, ibid., p. 1594.618 E. Goon, J. E. Petley, W. H. McMullan, and S. E. Wiberlev, ibid., p. 608.619 R. Bock and I<.-G. Hackstein, 2. anal. Chem., 1953, 138, 337.620 G. R. Price, R. J . Ferretti, and S. Schwarz, Analyt. Chem., 1953, 25, 322.621 C. L. VC'aring and C. S. Annell, ibid., p. 1174.622 B. McDuffie, J , Chem. Educ., 1953, 30, 454.623 F. A. Pohl, 2. anal. Chem., 1953, 139, 241.624 G. E. Heggen and L. W. Strock, Analyt. Chem., 1953, 25, 859.623 R. F.Meeker and R. C. Pomatti, ibid., p. 151.626 N. E. Gordon and R. M. Jacobs, ibid., p. 1605.613 M. Bobtelsky and Y . Welwart, ibid., pp. 281, 375368 ANALYTICAL CHEMISTRY.impurities where the impurities in the synthetic matching standards are notthe same as those in the unknown.627 Methods for the determination ofcalcium in biological materials have been reviewed.628 A rotating-discelectrode has been used in the determination of impurities in titaniumZirconium 6309 631 and hafnium 630 have been determined spectro-graphically. Gold has been concentrated from solutions in ethylcellulosebefore determinati~n.~~~ Methods have been proposed for the determina-tion of thorium and lanthanons in phosphate rock,633 for lanthanonsafter separation from uranium,634 for copper, cobalt, and molybdenumin plant materials,635 and for niobium in the presence of titanium andtantal~m.63~The flame photometer has been used to determine lithium in magnesiumalloys,637 sodium in Portland cement,638 and sodium and potassium in plantextracts,639 and other biological specimens.64o> 641 Calcium has been deter-mined in biological 642 and the alkaline-earth metals have beendetermined in mixtures.643Absorption Spectra.-The shift of low- and high-intensity absorptionbands with change of solvent has been investigated for a number of benzenederivatives and an attempt has been made to relate the shift to the natureof the interaction between the substituents and the s0lvent.~44 Either infra-red or ultra-violet absorption spectra can be used to provide a simple andspecific means of determining naphthalene.645 Flavones 646 have beenidentified by the ultra-violet absorption spectra of their ions in sodiumethoxide solution, and polynuclear hydrocarbons 646 as the correspondingmethoxy-compounds.647 The shift in absorption maxima shown by certainanthocyanins in the presence of aluminium chloride has been used 648 todistinguish them from similar compounds which show no shift.Infra-red spectroscopy has been used to distinguish the different poly-morphic forms of both organic and inorganic materials.649 For samples ofthe order of a microgram it has been recommended that a special beam-condensing system constructed from silver chloride lenses be used, andsamples of 10 pg.and upwards are pressed into 5-mg. potassium bromide627 J. K. Hurwitz, Analyt. Chem., 1953, 25, 1028.628 H.-U. Riethmiiller, Mikvochim. Acta, 1953, 178.629 H. A. Heller and R. W. Lewis, Analyt. Chem., 1953, 25, 1038.630 V. A. Fassel, A. M. Howard, and D. Anderson, ibid., p. 760.631 D. M. Mortimore and L. A. Noble, ibid., p. 296.632 J. A. Lewis and P. A. Serin, Analyst, 1953, '98, 385.633 C. L. Waring and H. Mela, Analyt. Chem., 1953, 25, 432.63.1 B, Helger and R. Rynninger, Svensk Kem. Tidskv., 1952, 64, 224.635 J. Smit and J. A. Smit, Analyt. Chim. Acta, 1953, 8, 274.1336 G. Charlot and J. Saulnier, Ann. Chim. analyt., 1953, 35, 51.637 E. E. Strange, Analyt. Chem., 1953, 25, 650.638 J. J. Diamond and L. Bean, ibid., p. 1825.639 H.M. Bauserman and R. R. Cerney, ibid., p. 1821.640 M. G. Woldring, Analyt. Chim. Acta, 1953, 8, 150.641 G. R. Kingsley and R. R. Schaffert, Analyt. Chem., 1953, 25, 1738.642 P. S. Chen and T. Y . Toribara, ibid., p. 1642.643 0. N. Hinsvark, S. H. Wittwer, and H. M. Sell, ibid., p. 320.644 H. E. Ungnade, J . Amer. Ckem. SOC., 1953, 75, 432.645 N. J. Klein and G. W. Struthers, Analyt. Chem., 1953, 25, 1818.646 G. H. Mansfield, T. Swain, and C. G. Nordstrom, Nature, 1953, 172, 23.647 R. L. Cooper, Chem. and Ind., 1953, 516.648 T. A. Geissman, E. C. Jorgenson, and J. B. Harborne, ibid., p. 1389.649 D. N. Kendall, Analyt. Chem., 1953, 25, 382WILSON : INSTRUMENTAL METHODS. 369tablets through which the beam is passed.650 Complex organic materialshave been identified by infra-red examination of the products producedunder controlled conditions of pyrolysis,651 and the mineral constituents ofrocks have been examined as a finely ground powder film spread on a rocksalt window.652 Aldehydes and ketones have been analysed as the 2 : 4-di-nitrophenylhydrazones.6s Differential methods are strongly recommendedfor accurate infra-red analysis, the difference in absorption for a particularband in the unknown sample and in a reference being determined.654In the last few years microwave spectroscopy, that is, determination ofthe absorption by matter of radiation with wave-lengths of 2-100 mm.(frequencies of 3000--150,000 Mc./sec.) has been developed, and this instru-mental method has found some applications to analytical problems.I t iscertain that the number and range of these applications will increase as themethod becomes more widely appreciated. The problems which have beendealt with hitherto are of a rather specialised nature, and several reviews ofpresent and possible future applications, as well as of the theoretical back-ground and instrumental methods, have recently appeared. 655-657Miscellaneous Instrumental Methods.-Simple and polynuclear aromaticcompounds have been detected unequivocally by the lise of a fusion techniqueunder the microscope, whereby the compound is allowed to react with2 : 4 : 7-trinitrofl~orenone.~~~ If the technique is properly followed, fourseparate melting points are obtained in a single experiment, these represent-ing that of the unknown itself, that of the addition compound between theunknown and the reagent, and those of the two eutectics formed by thetwo separate substances with the addition compound.This is recommendedas a general means of identifying the individuals of a limited class of com-pound, the requirement being that it is possible to find a suitable fusionreagent that will react with all the individuals. The behaviour of substanceswhich supercool before crystallisation, and the effect of this on the pseudo-eutectic temperatures recorded have been investigated by A. K0fler.65~9 660The determination of optical and crystallographic data for selected com-pounds which has been carried on throughout the past few years continues,and compounds for which data have been published include D-fructosehemihydrate,661 dibenzyl sulphide,662 5--hydroxytetra~ole,~~~ dibenzyl~ h t h a l a t e , ~ ~ ~ s ~ c c i n i m i d e , ~ ~ ~ lycoctonine monohydrate,666 trans-diethyl-stilbcestr01~~~7 l-naphthoic acid,668 ~alicylarnide,~~~ (A)-pinic acid,670660 D.H. Anderson and N. B. Woodall, Analyt. Chem., 1953, 25, 1906.G 5 1 D. L. Harms, ibid., p. 1140.652 J . M. Hunt and D. S . Turner, ibid., p. 1169.653 J. H. Ross, ibid., p. 1288.655 R. H. Hughes, Ann. N.Y. Acad. Sci., 1952, 55, 872.6s6 J. Sheridan, Chem. and Ind., 1953, 648.657 R. H. Hughes, Bull. Brit. Sci. I n d . Res. Assoc., 1952, 7, 37.658 I>. E. Laskowski, D. G. Grabar, and W. C. McCrone, AnaZyt. Chein., 1953, 25, 1400.659 iVlikrochem. Mikrochim Ada, 1952-1953, 40, 311.661 F.T. Jones, F. E. Young, and D. R. Black, Analyt. Chern., 1953, 25, 649.662 J. Krc and J. French, ibid., p. 198.663 K. Hattori, J. P. Horwitz, and E. Lieber, ibid., p. 353.664 J . Krc and W. Rila, ibid., p. 514.668 R. J. Hinch and W. C. McCrone, ibid., p. 675.666 R. M. Douglas and W. B. Cook, ibid., p. 836.667 H. A. Rose, R. J. Hinch, and W. C. McCrone, ibid., p. 993.6 6 8 W. C. McCrone, ibid.. p. 1126.669 W. C. McCrone and R. J. Hinch, ibid., p. 1277.654 C. F. Hammer and H. R. Roe, ibid., p. 668.6Go Ibid., p. 405.670 J. Krc, ibid.. p. 2420370 ANALYTICAL CHEMISTRY.erythromycin hydriodide h~drate,~7l hafnium oxide, Hf0,,672 2 : 3 : 4 : 6-te t ranitr oaniline, 672 met hylenebis- (N-pyrrolidone-2-carboxylic acid) ,673 and2-phenyl-1 : 2 : 3 : 2H-triazol-4-ylmethanol and related compounds.674The use of X-ray methods for analytical purposes has been extensivelyreviewed in a symposium.e75 Phosphates have been analysed by X-raymethods using magnesium oxide as an internal standard.6768.PHYSICAL SEPA4RATION METHODS.As pointed out in a previous Report,677 the divisions between some of theclasses of physical separation methods are so sketchily indicated that it isnot always possible to assign the methods with any degree of certainty. Asa consequence, although an attempt has been made to place most of themethods in their appropriate group, there must necessarily be considerableoverlap, and there must also be some work which is best assumed to havea general application.The types of separation in laboratory fractional distillation, and thebehaviour of non-ideal mixtures have been discussed.678 A method offractional crystallisation on paper,679 which is essentially similar to the long-established sensitive test for hzmin used in forensic work,68o bxt which maybe of more general application, has been described.Chromatography of inorganic materials, and in particular, partitionmethods, have been dealt with in two 691 There has been acritical examination of the factors influencing RF values in chromatographyon The Reporter’s warning 677 that artefacts may arise throughfailure to distinguish the forces being used in any particular separation hasbeen emphasised by the results published by a number of authors duringthe past year.D. P. Burma683 has shown that, although the primaryprocess responsible for many separations is undoubtedly partition, yet adsorp-tion by the cellulose, although a secondary phenomenon, cannot be neglected ;and much work is required before the mechanism for even the simplestseparations can be regarded as being on a sound footing. Other indicationsof the complicated processes are the observations that certain electrolytesare adsorbed as a whole on ion-exchange resins,684 the nature of the anion671 H. A. Rose, Analyt. Chem., 1953, 25, 1571.672 S. Geller and E. Corenzwit, ibid., p. 1774.673 I;. T. Jones, K. J. Palmer, and D. R. Black, ibid., p. 1929.674 R. N. Castle, Mikrochim. Acta, 1953, 196.6 7 5 H.A. Liebhafsky, Analyt. Chem., 1953, 25, 689; L. S. Birks, E. J. Brooks, andH. Friedman, ibid., p. 692; R. G. Steinhardt and E. J. Serfass, ibid., p. 697; M. E.Straumanis, ibid., p. 700; H. P. Iilug, ibid., p. 704; E. P. Bertin, ibid., p. 708; L. L.Merritt, ibid., p. 718; K. L. Yudowitsch, ibid., p. 721 ; R. Castaing and A. Guinier, ibid.,p. 724; W. F. Bradley, ibid., p. 727; S. F. Kern, ibid., p. 731 ; C. R. Hudgens and A. M.Ross, ibid., p. 734; B. Post and I. Fankuchen, ibid., p. 736; W. N. Lipscomb, ibid.,p. 737; J . Leroux, D. H. Lennox, and K. Kay, ibid., p. 740; C. W. Gould and S. T.Gross, ibid., p. 749; F. W. Neumann and C. W. Gould, ibid., p. 751.676 A. J. Mabis and 0. T. Quimby, ibid., p. 1814.6 7 7 Ann. Reports, 1952, 49, 333 et seq.678 E.F. G. Herington, Chem. and Ind., 1953, 26.679 R. C. Vasisth and M. S. Muthana, Natzrre, 1953, 172, 862.680 W. Ream and G. R. Freak, Biochem. J., 1915, 9, 161.683 Analyt. Chem., 1953, 25, 549.684 L. I . Katzin and E. Gebert, J . Amer. Chein. SOC., 1953, 75, 801.“ Chromatographic Methods of Inorganic Analysis,” F. H. Pollard and J. F. W.McOmie, London, 1953. 682 G. Zimmermann, 2. anal. Chem., 1953, 138, 321WILSON : PHYSICAL SEPARATION METHODS. 37 1of the resin and of the material being important ; that irreversible " absorp-tion" on to paper may take place through ion-exchange, whether thestationary phase is organic or water ; 685 that ion-exchange with the solventmay take place; 686 that salt interference may give rise to anomalous valcesin the chromatography of sugars; 687 that aldose and ketose sugars may beinterconverted by alkaline impurities in paper unless precautions are takento avoid such reaction ; 688 that where multivalent ions are concerned multiplespots frequently appear; 689 and that, as shown by an investigation in therange -50" to ZOO", temperature effects have a significant bearing onchromatographic separations.6s0Absorption Chromatography.-Reflectance photometry has been used todetermine quantitatively materials separated by paper chromat~graphy.~~~Cellulose sheets much thicker than ordinary filter-paper have beenrecommended as having a much greater loading capacity.G93 A holderfor a coiled strip allows a smaller containing vessel to be andrectangular pieces of paper with points or tongues on the edges have beenrecommended.695Chromatographic separations of pho~phate,~g~ niobium and tantalum,697and organo-metallic complexes,698 on alumina have been described.Thecopper complexes of pyridine bases 699 have been separated by mems ofpaper impregnated with copper chloride. Paper has been impregnatedwith 8-hydroxyquinoline ioo and alumina iO1 for the separation of cations,and with sodium hydrogen sulphite for the separation of aldehydes andketones.702 Cobalt has been separated i03 on an alumina column carryingnitroso-R salt; trace elements in water on a cellulose acetate column im-pregnated with a carbon tetrachloride solution of dithizone ; i04 and unsatur-ated organic acids on an alumina column impregnated with morin, whosefluorescence then indicates the zones.io5 Chromatographic separations ofmono- and di-saccharides, io6 pyrethrins, 'O7 vitamins, io8 and the methylesters of higher fatty acids i09 have been reported.The chromatography of gases and vapours, particularly with reference6 8 5 J. B. Schute, Nature, 1953, 171, 839.686 E. A. S. Cave11 and N. B. Chapman, Chew. and Ind., 1953, 1126; J. W. Baker6 8 7 S. Baar and J. P. Bull, ibid., p. 414. R. B. Duff, Chenz. and Ind., 1953, 898.689 A. S. Currey, Nature, 1953, 171, 1026.690 L. T. Chang, Analyt. Chem., 1953, 25, 1235.691 R. A. Wells, Quart. Reviews, 1953, 7, 307.692 S. V. Vaeck, Natuire, 1953, 172, 213.693 L. S. Cuendet, R. Montgomery, and F. Smith, J .Awzer. Chem. SOC., 1953, 75,695 F. Reindel and W. Hoppe, Naturwiss., 1953, 40, 245.696 M. A. Rangarajan, C. N. Venkatachallam, and B. S. Srikantan, J . Indian Chewt.698 A. A. K. Al-Mahdi and C. L. Wilson, Mikrochem. Mikrochim. A c f a , 1952-1!:63,700 Q. Fernando and J . P. Phillips, Analyt. Chenz., 1953, 25, 819.701 W. Kemula, Roczgz. Chenz., 1952, 26, 696.702 A. G. Newcombe and S. G. Reid, Nature, 1053, 172, 455.703 E. Jensen, Analyt. Chinz. Acta, 1952, 7, 561; J. A. Dean, Analyt. Chein., 1951,705 G. di Modica and P. F. Rossi, Ann. Chinz. analyt., 1952, 34, 271.' 0 6 W. 11. Corbett. Chenz. and I n d . , 1953, 1285. 707 J. Ward, ibid., p. 586.i o 8 J. A. Brown, Analyt. Chenz., 1953, 25, 774.709 F. R. Cropper and A. Heywood, Nature, 1953, 172, 1101.and A.J. Neale, Natiwe, 1953, 172, 583.2764. 694 V. Schwarz, Chem. and I d . , 1953, 102.SOL., 1953, 30, 281.40, 138.697 N. Tikhomiroff, Conzpt. rend., 1953, 236, 1263.J . Baudet, Conzpt. rend., 1952, 234, 2454.23, 1096. 704 D. E. Garritt, ibid., 1953, 25, 1927372 ANALYTICAL CHEMISTRY.to separations by displacement adsorption on charcoal columns, has beenextended. loIon Exchange.-Analytical applications of ion-exchange processes havebeen described 711 and a review has been made of the properties of differentAmerican , German, and Russian ion-exchange materials. 712 An extensivebibliography of analytical applications has been compiled. 713 Conductancemeasurements have been used to follow separations on ion-exchangecolumns.714 An indication has been given of a new use of ion-exchangeresins for the solution and determination of " insolubles " which may dis-solve when shaken during a period of time with a resin suspension, liberatingan equivalent amount of acid or alkali.7l3Ion-exchange separation has been used to determine copper in oils,715aluminium in zirconium,716 to separate iron and aluminium,717 to separatescandium, lanthanum, and yttrium,71s and lanthanons in general.7193 720The behaviour of ferric phosphate 721 and of platinum-group metals on ion-exchange columns has been investigated.7229 723Nitrate has been determined 724 and phosphate has been removed 7z5by ion exchange. I t has been stated that organic cations show a much moremarked pH dependence in relation to certain resins than do inorganiccations.726 Organic acids, 727y 728 organic salts, 729 aldehyde-ketone mix-tures , 730 sugars and related materials, 731-735 amino-acids and relatedmaterials,736> 737 proteins,73s and alkaloids 739 have been separated by ionexchange.The measurement of volume of resin beads has been extended to coverthe measurement of pH.740 The effect of certain cation-exchange resins onsolutions of oxidising materials has been investigated.'4l7 l O D. H. James and C. S. G. Phillips, J., 1953, 1600.7 l 1 0. Samuelson, " Ion-Exchangers in Analytical Chemistry," New York, 1953,7 l 2 D. I. Ryabchikov, M. M. Senyavin, and K. V. Filippova, J . Anal. Chem., U.S.S.R.,714 A. M. Baticle, Compt. rend., 1953, 236, 2055.715 H.Buchwald and L. G. Wood, Analyt. Chem., 1953, 25, 664.716 H. Freund and F. J. Miner, ibid., p. 564.7 1 7 H. Teicher and L. Gordon, Analyt. Chim. Acta, 1953, 9, 507.718 P. Radhakrishna, ibid., 8, 140.71s F. Trombe and J. Loriers, Compt. rend., 1953, 236, 1567.720 Idern, ibid., p. 1670.722 W. M. MacNevin and W. B. Crummett, Analyt. Chem., 1953, 25. 1628.723 P. C. Stevenson, A. A. Franke, R. Borg, and W. Nervik, J . Amer. Chem. Soc.,724 G. B. Jones and R. E. Underdown, Analyt. Chem., 1953, 25, 806.7!a5 R. B. Hahn, C. Backer, and R. Backer, Analyt. Chim. Ada, 1953, 8, 223.726 D. K. Hale, D. I . Packham, and K. W. Pepper, J., 1953, 844.727 H. H. Schenker and W. Rieman, Analyt. Chem., 1953, 25, 1637.72* H. S. Owens, A. E. Goodban, and J.B. Stark, ibid., p. 1507.729 C. H. van Etten and M. B. Wiele, ibid., p. 1109.730 G. Gabrielson and 0. Samuelson, Svensk Kem. Tidskr., 1952, 64, 150.731 J. D. Phillips and A. Pollard, Nature, 1953,171,41. 732 A. C. Hulme, ibid., p. 610.733 J. X. Khym and L. P. Zill, Nuclear Sci. Abstr., 1952, 6, 20.734 H. Zinner, Chem. Ber., 1951, 84, 780.735 M. A. Chambers, L. P. 221, and G. R. Noggle, J . Amer. Pharm. Rssoc., 1952, 41, 461.736 E. Schram, J. P. Dustin, S. Moore, and E. J. Bigwood, Analyt. Chim. Ada, 1953,738 N. I<. Boardman and S. M. Partridge, Nature, 1953, 171, 208.73s W. G. H. Edwards, Chem. and Ind., 1953, 488.740 C. Calmon, Analyt. Chem., 1953, 25, 490.7 4 1 N. Hartler and 0. Samuelson, Analyt. Chinz. Acta, 1953, 8, 130.E. L.Streatfield, Chenz. and I n d . , 1953, 1214.1952, 7, 135. 713 G. H. Osborn, Analyst, 1953, 78, 221.721 J. E. Salmon, J., 1953, 2644.1953, 75, 4876.9, 149. 737 J. S. Wall, Analyt. Chem., 1953, 25, 950WILSON : PHYSICAL SEPARATION METHODS. 373Extraction.-In a symposium on solutions of electrolytes in organicsolvents 742 the factors influencing extraction have been discussed.The partition of metal bromides between aqueous hydrobromic acid anddiethyl ether has been investigated. 743 Antimony(v) in hydrochloric acidsolution can be extracted by ethyl acetate.744 An a-butyl phosphate-carbontetrachloride mixture has been recommended for the extraction of metalthi~cyanates.'~~ Beryllium can be extracted by chloroform or ethyl acetateas the b ~ t y r a t e .~ ~ ~ Thorium has been extracted from pitchblende residuesby tributyl phosphate and tetraethyleneglycol dibutyl ether.747 The fluoridecomplexes of tantalum and niobium can be extracted and separated by usingdiisopropyl ketone,748 and zirconium and niobium as the mixed butylphosphoric acids can be extracted by di-n-butyl ether.749 In the determin-ation of phosphate, molybdophosphoric acid is the most suitable form forextraction and the most useful solvent is 20% butanol in chloroform.75oTitanium as cupferrate can be extracted with chloroform in the determin-ation of aluminium in titanium The copper-dithizone system inwater-carbon tetrachloride has been It has been noted thatextractions of diethyldithiocarbamates at low pH should be carried outrapidly owing to instability of the reagent.753 Disubstituted dithiocarb-amates have been used for extraction separations in the analysis of copperalloys.754 Technetium has been isolated by extraction as t etraphenyl-arsonium pert echnat e with chloroform. 755Partition Chromatography.-The existing technique for two-dimensionalpaper chromatography has been simplified by running spots obtained fromone solvent system on to separate strips for the application of further solventsystems. 756 Various techniques using circular disc paper chromatographyhave been r e ~ o r n m e n d e d . ~ ~ ~ - ~ ~ ~ A method has been devised for the auto-matic measurement of light absorption or fluorescence in paper separ-a t i o n ~ . ~ ~ ~ The relation between zone size and amount has been investig-ated.761 It has been suggested that there are numerous solvent systems inwhich gradient-elution analysis, that is, analysis with a continuously changingsolvent system, would be an improvement,762 and several instances of suchsystems are cited. H.S. Burton has stated that a very satisfactory support742 N. N. Greenwood, Nature, 1953, 172, 149.743 R. Bock, H. Kusche, and E. Bock, 2. anal. Chem., 1953, 138, 167.744 C. E. White and H. J. Rose, Analyt. Chem., 1953, 25, 351.745 L. Melnick, H. Freiser, and H. F. Beeghly, ibid., p. 856.746 A. K. Sundaram and S. Banerjee, AnaZyt. Chim. Acta, 1953, 8, 526.747 D. F. Peppard, G. Asanovich, R. W. Atteberry, 0. Du Temple, M. V. Gergel,A. W. Gnaedinger, G.W. Mason, V. H. Meschke, E. S. Nachtman, and I. 0. Winsch,J . Amer. Chem. Soc., 1953, 75, 4576.748 P. C. Stevenson and H. G. Hicks, Analyt. Chem., 1953, 25, 1517.749 E. M. Scadden and N. E. Ballou, ibid., p. 1602.750 C. Wadelin and M. G. Mellon, ibid., p. 1668.751 J. A. Corbett, Analyst, 1953, '78, 20.762 R. W. Geiger and E. B. Sandell, Analyt. Chim. Acta, 1953, 8, 197.753 A. E. Martin, Analyt. Chem., 1953, 25, 1260.7 5 4 F. F. Miller, K. Gedda, and H. Malissa, Mikrochem. Mikrochim. Acta, 1952-1953,756 F. P. W. Winteringham, Nature, 1953, 172, 727.7 5 7 K. V. Giri, ibid., 171, 1159.759 A. Saifer and I. Oreskes, Analyt. Chem., 1953, 25, 1539.760 J, A. Brown and M. M. Marsh, ibid., p. 1865.761 R. S. Srikantaii and C. N. Venkatachallum, J . Indian Chem.SOC., 1953, 30, 167.'62 M. Lederer, Nature, 1953. 173, 727.40, 373. 755 S. Tribalat and J. Beydon, Analyt. Chim. Acta, 1953, 8, 22.7 5 * H. Proom and A. J, Woiwod, ibid., p. 42374 ANALY 1 lLAL C ~ H c l V l l 3 l R I.is obtained by acetylation of the cellulose in ~ a p e r , 7 ~ ~ and asbestos chromato-graphy has been applied to a number of separations of inorganic cationpairs. 7G4Identification of spots on paper may be made specific by using successiveclipping in reagents, which must be applied in the correct order t o achievethis Ions with the same half-wave potential can first beseparated by chromatography before examining them polarographically. 7 6 7 9 768Partition chromatography has been used for the separation of lithium,sodium, and potassium,769 beryllium from aluminium and iron,77o traceimpurities in tin-lead alloys,771 analytical groups 111, IV, and V,772 alumin-ium in water,773 molybdenum, copper, and iron,774 thallium in organicmaterials,775 the per-compounds of titanium, vanadium, and molybdenum,776vanadium and molybdenum, 7 7 7 y 778 lanthanons, 779 radioactive isotopes frominactive material,7*0 uranium, copper, and iron,781 radium-D, -E, and -F, 782and actinium degradation products including francium.7833 784 The effectof potassium cyanide on the R p values of inorganic cations has beenstudied. 785Partition chromatography has been used in the analysis of hydrogenperoxide-organic peroxide mixtures,413 organic acids, 786-791 alcohols, 793y 793phenols, 7949 795 keto-acids, 796, 797 sugars and related substances, 798-802766763 Chem.and Ind., 1953, 1229.765 I. Smith, Nature, 1953, 171, 43.7 6 6 J . B. Jepson and I. Smith, ibid., 172, 1100.7 6 7 W. Kemula, Roczn. Chem., 1952, 26, 694.7~ W. Kemula and A. Gbrski, ibid., p. 639.76n D. P. Burma, Analyt. Chinz. Acta, 1953, 9, 513.770 C. L. Rao and J. Shankar, ibid., 8, 491.771 J. R. Bishop and H. Liebmann, Analyst, 1953, 78, 117.772 J. G. Surak, N. Leffler, and K. Martinovich, J . Chem. Educ., 1953, 30, 20.773 K.-E. Quentin, 2. anal. Chem., 1953, 139, 92.774 F. H. Pollard, J. F. W. McOmie, H. M. Stevens, and J. G. Maddock, J . , 1953,7 7 5 H. Diller and 0. Rex, 2. anal. Chem., 1952-1953, 137, 241.7 7 6 M. Lederer, Annlyt. Chim. Acta, 1953, 8, 259.7 7 7 A. Lacourt, G.Sommereyns, J. Hoffmann, S. Frank-Frederic, and G. Wantier,7 7 8 A. Lacourt, G. Sommereyns, A. Stadler-Denis, and G. Wantier, Mikrochem.7 7 9 M. Lederer, Compt. rend., 1953, 236, 1557.780 Idem, Analyt. Chim. Acta, 1953, 8, 134.7a1 A. Weiss, S. Fallab, and H. Erlenmeyer, Helv. Chim. Acta, 1952, 35, 1588.782 E. E. Dickey, J . Chem. Educ., 1953, 30, 525.783 M. Perey and J. P. Adloff, Compt. rend., 1952, 236, 1664.784 Idem, ibid., p. 1163. 785 W. F. Pickering, Analyt. Chim. Acta, 1953, 8, 344.786 J. E. LofAer and E. R. Reichl, Mikrochim. Acta, 1953, 79.787 A. R. Jones, E. J . Dowling, and W. J. Skraba, Analyt. Chem., 1953, 25, 394.788 J. W. Airan, G. V. Joshi, J. Barnabas, and R. W. P. Master, ibid., 1953, 25, 659.789 S.S. Phatak, A. P. Mahadevan, and V. N. Patwardhan, Curr. Sci., 1952, 21, 162.790 R. E. B. Duncan and J. W. Porteous, Analyst, 1953, 78, 641.791 H. J. Nijkamp, Nature, 1953, 172, 1102.792 A. Siegel and K. Schlogl, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 383.793 S. dal Nogare, Analyt. Chem., 1953, 25, 1874.794 K. Schlogl and A. Siegel, Mikrochem. Mikrochim. Acta, 1952-1953, 40, 202.7Q5 T. R. Sweeney and J. D. Bultman, Analyt. Chem., 1953, 25, 1358.7~ D. J. D. Hockenhull, G. D. Hunter, and M. W. Herbert, Chem. and Id., 1953,797 D. Turnock, Nature, 1953, 172, 355.798 D. Gross and N. Albon, Analyst, 1953, 78, 191.79n B. D. E. Gaillard, Nature, 1953, 171, 1160.S. Gardell, Acta Chem. Scand., 1953, 7, 201,801 R. H. Bayly and E. J. Bourne, Nature, 1953, 171, 385.808 D. J.D. Hockenhull. Nature, 1953, 171, 982.764 B. N. Sen, Australian J . Sci., 1953, 15, 133.1338.ibid., p. 444.Mikrochim. Acta, 1952-1953, 40, 268.127U’ILSON : MISCEL1,ANEOUS. 375amines, 803 amino-acids, 804-808 phosphate esters, 809 t hioureas, 810 and com-pounds related to adrenaline.811Ionophoresis and Electrophoresis.-The mechanism of electrophoresison paper has been d i s c ~ s s e d . ~ ~ ~ - ~ ~ ~ An apparatus which can be applied to2 ml. of solution instead of the 11 ml. required by the standard apparatushas been described.815 Separations have been made of calcium and phos-phate ions,s16 lanthanons,sl7 amino-acids,818 sugars,819-822 vitamins,s2Aand keto-acid dinitrophenylhydra~ones.~~~Separations using high frequencies of 500-5000 k ~ ./ s e c . ~ ~ 5 and highvoltages of 40-60 v/cm. for long periods 826 have been described.9. MISCELLANEOUS.Radiochemical Analysis. -Applications of radio-isot ope techniques inanalytical chemistry have been surveyed 827-829 and isotope dilution methodshave been reviewed.830 Methods have been described for the synthesis oflabelled organic compounds. 831 Apparatus and counting techniques havebeen d e s ~ r i b e d . ~ ~ ~ - ~ ~ ~ Cations have been determined by the use of radio-active hydrogen s~lphide,~~5 potassium has been determined as cobalti-nitrite by use of radioactive c0balt,8~~ and the determination of germaniumhas been investigated by tracer methods.837 Zinc in aluminium alloys hasbeen determined by use of 65Zn.838 Analytical processes for zinc have beenevaluated for the gravimetric determination of zinc, tracer methods beingA.Wankmiiller, Naturwiss., 1952, 39, 133.R. C. Salander, M. Piano, and A. R. Patton, .4nalyt. Chem., 1953, 25, 1252.G. Curzon and J. Giltrou, Nature, 1953, 172, 356.A. P. Prior and T. P. Whitehead, ibid., p. 358.G. Ray, N. C. Ganguli, and S. C. Ray, ibid., p. 809.A. L. Levy and D. Chung, Analyt. Chem., 1953, 25, 396.E. Fletcher and F. H. Malpress, Nature, 1953, 171, 838.*lo A. Kjaer and K. Rubinstein, Acta Chem. Scund., 1953, 7, 528.811 D. M. Shepherd and G. B. West, Natzcre, 1953, 171, 1160.M. A. Jermyn and R. Thomas, ibid., 172, 72s.A. Tiselius, Discuss. Faraday Soc., 1953, 13, 29.M. Macheboeuf, Chenz.Weekblad, 1953, 49, 237.815 L. G. Longworth, Analyt. Client., 1953, 25, 1074.T. R. Sato, W. E. Kisieleski, W. P. Norris, and H. H. Strain, ibid., p. 432.M. Lederer, Compt. regzd., 1953, 236, 200.D. P. Burma, Analyt. Chim. Acta, 1953, 9, 518.F. Micheel and F.-P. van der Kamp, Angew. Clzem., 1952, 64, 607.8 ~ 0 L. Jaenicke, Naturwiss., 1952, 39, 86.822 A. B. Foster and M. Stacey, J . Appl. Chem., 1953, 3, 19.823 E. S. Holdsworth, Nature, 1953, 171, 148,a24 W. J. P. Neish, Rec. Trav. chim., 1953, 72, 105.825 Y. Hashimoto and I. Mori, Nature, 1953, 172, 542.826 D. Gross, ibid., p. 908.s27 “ Proceedings of Isotope Techniques Conference,” Vol. 2, London, H.M.S.O.,820 H. Seligman, Nature, 1953, 171, 588.830 J. J. Pinajian, J. E. Christian, and W.E. Wright, J . Amer. Pharm. Assoc., 1953,831 S. L. Thomas and H. S. Turner, Quart. Reviews, 1953, 7, 407.832 R. E. Connally and M. B. Leboeuf, Annlyt. Chem., 1953, 25, 1095.833 H. W. Kirby, ibid., p. 1238.834 E. A. Evans and J. L. Huston, Nuclear Sci. Abstr., 1952, 6, 211.835 P. C. van Erkelens, Nature, 1953, 172, 358.a36 E. Sanchez Serrano and I. Lopez Santos, Bol. radioact., Madrid, 1951, 24, 49.s37 L. K. Bradacs, 1.-M. Ladenbauer, and F. Hecht, Mikrochim. Acta, 1953, 229.838 K. Theurer and T. R. Sweet, AnaZyt. Chem., 1053, 25, 119.821 A. B. Foster, J . , 1953, 982.1952. P. C. Aebersold and E. A. Wiggin, J . C h e w Educ., 1953, 30, 229.42, 301; J. E. Christian and J . J. Pinajian, ibid., p. 304376 ANALYTICAL CHEMISTRY.u ~ e d .~ 3 ~ Niobium and tantalum 8403 841 and titanium 841 have been deter-mined radiochemically.Radioactivation.-Deuterium has been determined by measurement ofthe neutron emission in conjunction with a suitable source of y - r a y ~ . ~ ~ Neutron irradiation has been applied to the determination of copper,843thallium,844 metallic impurities in high-purity iron,845 tantalum,846 andthe rare uranium isotope (235U) in naturally occurring uranium. 847W. W. Meinke and R. E. Anderson 848 have investigated fully the possi-bility of using low-level neutron sources for activation analysis, and havedescribed the use of this method in the determination of silver, indium, andrhodium.Gas Analysis.-Apparatus for the microanalysis of 20 cu. mm. of gas 849and a simple procedure for the analysis of a sample of the order of severalcu. mm.850 have been described. Winkler-type apparatus for the determin-ation of oxygen,S51, 852 simplified Hempel pipettes,853 apparatus for theanalysis of fuel gases by combustion with oxygen,s54 and a photoelectricinstrument for continuous detection of hydrogen sulphide 855 have beenused.A reliable method for preparing ammoniacal cuprous chloride solutionfor absorption of carbon monoxide has been reported.856 Oxygen in metallicoxides has been determined by treatment with bromine trifluoride, 857 andan electrochemical determination of oxygen is possible by using the depolar-isation of a carbon cathode.858 Apparatus and methods for the determin-ation of oxygen in metals have been d e s ~ r i b e d .~ ~ ~ - ~ ~ ~Direct gas-gas titrations, using pressure measurements to evaluate theend-point, may be used to take advantage of the reactivity of many gaseoushalogen derivatives3 Thus chlorine, fluorine, chlorine monofluoride, andchlorine trifluoride can be titrated with gaseous hydrocarbons , and chlorinetrifluoride-fluorine or methane-ethane mixtures are examples of morecomplex systems which can be analysed by this means.Non-aqueous Solvents.-In titrations using non-aqueous solvents it has839 J . E. Vance and R. E. Borup, Analyt. Chem., 1953, 25, 610.840 T. F. Boyd and M. Galan, ibid., p. 1568.841 J . Beydon and C. Fisher, Analyt. Chim. Acta, 1953, 8, 538.842 C. P. Haigh, Nature, 1953, 172, 359.843 J . Pouradier, A.M. Venet, and H. Chateau, Anm. Chirn. analyt., 1953, 35, 125.844 C. J. Delbecq, L. E. Glendenin, and P. H. Yuster, Analyt. Chern., 1953, 25, 350.845 P. Albert, M. Caron, and G. Chaudron, Compt. rend., 1953, 236, 1030.846 A. Kohn, ibid., p. 1419.847 A. P. Seyfang and A. A. Smales, Analyst, 1953, 78, 394.848 Analyt. Chem., 1953, 25, 778.8 p 0 D. G. Madley and R. F. Strickland-Constable, Analyst, 1953, 78, 122.850 H. G. Heal, Nature, 1953, 172, 30.851 L. P. Pepkowitz and E. L. Shirley, Analyt. Chem., 1953, 25, 1718.852 E. L. Harper, ibid., p. 187.854 W. J. Gooderham, ibid., p. 477.855 L. Aldred and J . Clough, Ind. Chem. Chem. Manuf., 1953, 29, 515.8b6 B. B. Bach, J. V. Dawson, and L. W. L. Smith. Cham. and Ind., 1953, 1279.857 H. R. Hoekstra and J . J . Katz, Analyt. Chem., 1953, 25, 1608.858 M. G. Jacobson, ibid., p. 586.850 J . N. Gregory, D. Mapper, and J . A. Woodward, Analyst, 1953, 78, 414.860 W. J . McMahon and L. S. Foster, J. Chem. Educ., 1953, 30, 609.861 M. W. Mallett, A. F. Gerds, and C. B. Griffith, Amalyt. Chem., 1953, 25, 116.862 C. €3. Griffith and M. W. Mallett, ibid., p. 1085.863 W. S. Horton and J. Brady, ibid., p. 1891.853 R. W. Green, Chenz. and I d . , 1953, 103WILSON MISCELLANEOUS. 377been found 864 that proper selection of the solvent, or addition of varyingamounts of a different non-aqueous solvent, may markedly increase the easewith which the end-point can be determined. Weak bases such as tertiaryamines show a sharper break in the potentiometric titration curve whentitrated in acetic anhydride solvent mixtures.865 Phenols can be titrated indimethylformamide by using azo-violet as indicator, or in ethylenediaminewith o-nitroaniline as indicator. 866 High-frequency titrations of organicbases have been carried out in glacial acetic acid-perchloric acid mixtures.867A4pparatus made of polychlorotrifluoroethylene has been recommended forstudies, in particular polarographic, in hydrogen fluoride solvent systems. 868Catalysed Reactions-Iodine has been determined by measuring itscatalytic action on the rate of the reaction between cerium(1v) andarsenic(II1) 869-87l or by its catalytic effect on the fading of the ferric thio-cyanate colour.872 Osmium has been determined in submicrogram amountsby its catalytic action on the cerium(Iv)-arsenic(III) reaction.873 In additionto iodide, ruthenium also acts as a catalyst, but its effect can be prevented.Miscellaneous Methods.-Determina tion of water by Karl Fischer’smethod has been reviewed. 874 Sulphur dioxide and bromine in chloroformhave been used in the same way as the Karl Fischer reagent to determinewater in inert organic solvents.s75 A sharp visual end-point is given, butthe titration is interfered with by alcohols.Deuterium determinations have been improved by reducing the interiorsurfaces of the apparatus used for the reduction of water by zinc, thusreducing the “ memory ” effects of the walls in the isotopic e~timation.~7~Sedimentation methods have been applied to the semi-quantitativedetermination of lead, mercury, tungsten, silver,877 and vanadium 878in microgram samples of material. A coefficient of variation of 5-13% hasbeen recorded in these determinations.Automatic thermometric titrations have been carried out by use of athermistor, a potentioneter, and a constant-flow burette, and acid-base andprecipitation reactions have been successfully carriedSeveral determinations have been described which depend on measuringthe time of induction in well-known “ time reactions.” Thus fluoride hasbeen determined by measuring the amount by which it accelerates thereaction between iodide and the hydrolysis products of cerium(1v) ,880 thio-sulphate has been determined by the time taken for the appearance of864 C. W. Pifer, E. G. Wollish, and M. Schmall, Analyt. Chem., 1953, 25, 310.8 6 5 J. S. Fritz and XI. 0. Fulda, ibid., p. 1837.J. S. Fritz and R. T. Keen, ibid., p. 179.867 W. F. Wagner and W. B. Kauffman, ibid., p. 538.8 6 8 J. W. Sargent, A. F. Clifford, and W. R. Lemmon, ibid., p. 1727.8e9 G. H. Ellis and G. D. Duncan, ibid., p. 1558.870 A. Schleicher, 2. anal. Chem., 1952-1953, 137, 401.8 7 1 B. Rogina and M. DubravEiC, Analyst, 1953, 78, 594.8 7 2 I. Iwasaki, S. Utsumi, and T. Ozawa, Bull. Chem. SOC. Japan, 1953, 26, 108.873 R. D. Sauerbrunn and E. B. Sandell, Mikrochim. Acta, 1953, 22.8 7 4 V. G. Jensen, Dansk Tidskr. Farm., 1952, 26, 145, 170.875 R. Belcher and T. S. West, J., 1953, 1772.876 C. A. Dubbs, Aqzalyt. Chem., 1953, 25, 828.8 7 7 H. M. El-Badry and C. L. Wilson, Mikrochem. Mikrochiin. A d a , 1952-1953, 40,879 H. W. Linde, L. B. Rogers, and D. N. Hume, Analyt. Chem., 1953, 25, 404.225. 8 7 8 Idem, ibid., p. 230.J. L. Lambert, ibid., p. 271378 ANALYTICAL CHEMISTRT.cloudiness on addition of a standard amount of acid, and iodate or sulphitehave each been determined by the induction period in a mixture with aknown amount of the other.881 Copper content can be determined bymeasuring the time taken to decolorise ferric thiosulphate in the presence ofthiocyanate.ss2So-called " electron-exchange " polymers have been described.883$ 884These may be used to cause oxidation or reduction on a column, and arereversible, although not quantitatively so. However, unlike normal reduc-tors, the columns do not contaminate the solution being treated with otherions. It is pointed out that these resins in effect produce reactions of atype forecast by M. Tswett 885 in his early investigations on chromatographicseparations. Both batch and counter-current applications of the resins havebeen suggested.884Racemic mixtures have been resolved by fractional precipitation froma non-active solvent,886 and the statistical basis of such a separation hasbeen discussed. Electrophoresis in a strong centrifugal or magnetic fieldshould also, it has been claimedJa87 be capable of resolving mixtures ofstereoisomers.Chemical methods for the characterisation of bacteria have been re-viewed 888 and improvements have been proposed to the existing analyticalchemical tests.C. L. WILSON.S81 E. N. Ponomareva, J . Anal. Cheni., U.S.S.K., 1952, 7, 163, 168.882 H. Got8 and S. Suzutu, Sci. Rep. Res. Inst. TGhoku Univ., 1952, 4, 35.883 M. Ezrin, I. H. Updegraff, and H. G. Cassidy, J . Amer. Chem. Soc., 1953, 75, 1610.884 Idem, ibid., p. 1615.8e5 M. Tswett, Ber. Deutsch. bot. Ges., 1906, 24, 316.8 8 6 R. C. Ferreira, Nature, 1953, 171, 39.887 F. C. Lendrum, ibid., 172, 499.888 S. T. Cowan, Chem. mzd Ind., 1953, 883