ANALYTICAL CHEMISTRY.IN this year’s Report it has been considered desirable to treat microwavespectroscopy in some detail, because hitherto it has received but passingmention. The remainder of the Report follows, in general, the pattern ofthe previous two years. It has not been possible to cover every aspect ofthe vast expanding field of analytical chemistry.During the last three years great strides have been made in many branchesof analytical chemistry and it is not an easy matter to look back and singleout a few for special mention. Particular interests will undoubtedly playsome part in making such a selection.Amongst the more interesting trends is the increasing application offlame photometry to the rapid determination of metals other than the alkaliand alkaline-earth metals.More widespread applications are being foundfor the high-frequency titration technique, although at present, mostattention is being focused on the selection of the best type of instrumentand its mode of application. A more general interest in the application ofelectrophoresis to inorganic analysis is now evident. In classical analysis,pride of place must go to the many and varied applications of ethylene-diaminetetra-acetic acid (EDTA), both as a masking agent and as a titrant.There has been a lack of a range of suitable indicators until fairly recently,but during the last year or so, several new indicators have been developed.Future work in this field will undoubtedly lie in the development of furtherindicators, and in a search for reagents inore selective than EDTA itself.Generaladvises caution in the application of statistics to theevaluationof analytical results, because proper consideration is never given to theinherent chemical errors of methods.He recommends that the averageerror (the arithmetical mean of the absolute values of the individual deter-minations from the mean of the results) be calculated and transformed to afigure approximating to the standard deviation by multiplying by 1.25.Benedetti-Pichler has listed a number of rules which should be followedin order to attain the highest precision inherent in a given balance. Recenttrends in the design of niicrobalances have been re~iewed.~A procedure for the concentration of traces of copper, antimony, andbismuth has been de~cribed.~ Lead nitrate is added and the solution istreated with zinc filings.The trace metals are co-precipitated with lead.The metal is filtered off and dissolved in nitric acid. The individual metalsare then determined as follows : bismuth polarographically, antimony colori-metrically by the reaction with methyl-violet, and copper titrimetrically.Babko1 A. K. Babko, Zavodskaya Lab., 1955, 21, 269.a A. A. Benedetti-Pichler, Mikrochim. Acta, 1956, 565.3 G. I?. Hodsman, ibid., p. 591.V. V. Ten’kovtsev, Zavodskaya Lab., 1955, 21, 525BELCHER, SHERIDAN, STEPHEN, AND WEST. 333Lingane and Davis have used argentic oxide as an oxidant to transformmanganese(II), cerium(m), and chromium(Ir1) to higher valency states.Theexcess of oxidant is simply removed by warming to decompose silver(i1).The solution is then titrated with standard ferrous sulphate. The reagenthas an advantage over the conventional bismuthate or persulphate reagentsin that chloride ion does not interfere. The procedure has been applied tothe analysis of alloys.Powdered antimony and nickel have been re-examined as reducingagents6 Antimony reduces iron(II1) and tin(1v) in 3--6~-hydrochlork orsulphuric acid. Titanium(1v) is reduced in 10N-sulphuric acid and can betitrated with methylene-blue without removing the excess of reductant.Uranium(v1) and tungsten(v1) are reduced in 6~-sulphuric acid and are thentitrated with ferric alum solution. Nickel appears to have no advantageover lead in a reductor column : although reduction is as efficient, the colourof the nickel ion may interfere.An alternative to the Zimmermann-Reinhardt reagent for the suppres-sion of interference by chloride in the permanganate titration of iron(r1) hasbeen described.’ Several compounds were examined but the best resultswere obtained with a mixture of potassium fluoride and sodium sulphate.Advantages of the reagent are cheapness, ease of preparation, and improve-ment of the end-point, but it is less effective when hydrochloric acid is presentin excess of the amount usually left after dissolution of an ore.The authorsdo not mention that this mixture was criticised adversely by Follenius 8over 80 years ago.A detailed study has been made of the required cooling period forporcelain crucibles contained in a desiccator.D It was concluded that evenafter cooling for 1 hour significant errors are obtained ; these may be minim-ised by allowing the crucible to cool somewhat before placing it in thedesiccator, by restricting the number of crucibles in the desiccator, and, ifthe substance is non-hygroscopic, by allowing the crucible to stand in thebalance-case before weighing.The interfering effect of induced reactions in titrimetric and colorimetricanalysis has been discussed.1° Two types of reaction are considered:(a) coupled reactions in which substance A (actor) reacts with both B(inductor) and C (acceptor} in a fixed ratio, and (b) chain reactions in whichthe actor A reacts only with the acceptor C.Several examples of each typeare given.The significance of steric factors in the application of organic compoundsas reagents has been discussed.ll Particular reference is made to this effecton the reactions of benzidine, crystal-violet, and various azo-dyes.The analytical properties of substituted 2 : 4 : 6-trinitrophenols haveJ. J. Lingane and D. G. Davis, Analyt. Chim. Acta, 1056, 15, 201.C. Yoshimura, J . Chem. SOC. Japan, 1955, 76, 409.K. M. Somasundarum and C. V. Suryanarayana, 2. anorg. Chena., 1954,277, 181 ;T. Agterdenbos, Analyt. Chim. Acta, 1956, 15, 429.cf. idenz, Acta Chim. Hung., 1956, 8, 423. * 0. Fellenius, 2. analyt. Chem., 1872, 11, 177.lo ’A. I. Medalia, Analyt. Chem., 1955, 27, 1678.11 I. S. Mustafin, T. I.Badayeva, and L. M. Knl’berg, Ukvaiiz. hhim. Zhzcr., 1955,21, 381334 ANALYTICAL CHEMISTRY.been examined.12 Those compounds which were highly hindered stericallyshowed great selectivity : for example, methylpropylpicric and ethylmethyl-picric acids precipitated barium quantitatively, but not strontium ; di-methylpicric acid precipitated strontium and barium but not calcium ; andmethylpropylpicric acid did not precipitate lanthanum, but precipitatedcerium(m), lead, and silver.Henning l3 has reviewed work concerned with the relationships betweenthe analytical properties of an organic reagent and the stability of themetal-ion complex formed ; he details the factors which affect the stability.Several substituted thiocarbazone derivatives have been synthesisedand the absorption maxima with various metals have been determined.l4The complexes with lead, mercury(II), zinc, and silver have a single absorp-tion maximum in the short-wave region at longer wavelengths than thoseformed with diphenylthiocarbazone.The important investigations of G.F. Smith and his co-workers havecontinued. l5 Eleven new substituted 1 : 10-phenanthrolines have beensynthesised ; the wavelengths of maximum absorption and the molecularextinction coefficients of the ferrous and cuprous complexes have beendetermined.Agterdenbos16 has prepared a complete survey of methods based onprecipitation from homogeneous solution. Their applications in gravimetricanalysis and advantages are critically discussed.Wilson l7 has given a general survey of ultramicro-methods with specialreference to the methods used for weighing and titration.The range isdefined as an operation carried out on a sample ofBarcia l8 has reviewed thermogravimetric methods in analysis and thevarious types of thermobalance which are available.g. or ml.ReagentsPrecipitants.-Oxalhydroxamic acid has been used for the gravimetricdetermination of lead; l9 no details of possible interferences are supplied.Mercury(1) can be determined gravimetrically or conductometrically byprecipitation with coumaric acid; 2o large amounts of mercury(I1) do notinterfere.Further new reagents for nickel and copper have been recommended.21S-Methylthiuronium sulphate precipitates both metals as methyl mercaptideswhich can be weighed as such.Separation can be achieved by altering theThe method appears to be very sensitive.l2 C. E. Moore, M. M. Lally, R. L. Anderson, J. L. Brady, and J. J. McLafferty,l* G. J. Henning, Chem. Weekblad, 1955, 51, 519.l4 L. S. Pupko and P. S. Pel'kis, Zhur. obshchei Khim., 1954, 24, 1640.l 5 D. H. Wilkins, A. A. Schilt, and G. F. Smith, Analvt. Cham., 1955, m, 1574.l6 T. Agterdenbos, Chem. Weekblad, 1955, 51, 571.l' C. L. Wilson, Mikrochim. Ada, 1956, 91.l 8 C . G. Rarcia, Iizf. Quim. Anal., 1956, 9, 159.l B I. P. Ryazanov and T. I. Badeeva, Ref. Zhur., Khim., 1955, Abstr. No. 14,219.2o A. Waksmundzki and R. Szucki, Ann. Univ. M . Curie-Sklodowska, A A . 1954.21 S. K. Siddhanter and P. C. Kundu, J . Indian Chem. SOC., 1955, 32, 655Analyt.Chim. Acta, 1956, 15, 1.8, 17BELCHEK, SHEKIDAN, STEPHEN, AND WEST. 335medium, but a double precipitation is necessary. Various thiosemi-carbazones have been recommended as reagents for the same two metalsand for cobalt.22The most promising of the new reagents for nickel is 4-methylcyclo-hexane-1 : 2-dione d i ~ x i m e . ~ ~ The desirability of using water-solubledioximes has been appreciated for many years, but the only one of thistype so far studied in detail, cyclohexane-1 : 2-dione dioxime, is co-precipit-ated with the nickel complex. The corresponding heptoximes, althoughfree from this defect, are difficult to synthesise, and oximes with less than6 carbon atoms in the ring require strict pH control for quantitative pre-cipitation.Accordingly, Banks and Hooker examined some substitutedcyclohexane-1 : 2-dione dioximes. The 4-methyl and the 4-isopropylderivative were found to be suitable. The 4-methyl compound is water-soluble ; it precipitates nickel at pH 3 and the precipitate is uncontaminatedwith excess of reagent. The 4-isopropyl compound has similar properties,but is less soluble in water and is recommended for micro-determinations.Both reagents are also suitable for the determination of palladium.9-Thiocyanatoaniline has been recommended as a reagent for the gravi-metric determination of palladium.24 Sogani and Bhattacharya 25 use3-hydroxy-1 : 3-diphenyltriazen for the same purpose. Certain phthalanilicacids have also been proposed.26New reagents for thorium continue to pour out in what appears to be anever-ending stream. The time has come for all this work to be reviewedand an assessment to be made of the relative merits of these reagents.Datta and Banerjee27 have examined 4-aminosalicylic acid as a pre-cipitant ; the determination may be completed gravimetrically or titri-metrically.Diphenic acid 28 and various organic bases 29 (o-anisidine ando-phenetidine) have also been recommended. Datta 30 examined severalphthalanilic acids and found that three precipitated thorium quantitatively.A further reagent which has been proposed is P-hydroxyamino-p-phenyl-- propionic acid.31 Few ions interfere.Gallium may be determined gravimetrically or nephelometrically byprecipitation with tetramethylenedithiocarbamic acid.32 The method hasbeen applied to the analysis of minerals, in which case gallium is firstextracted with ethyl ether.A new reagent for potassium, 2 : 4-dinitro-N-(2 : 4 : 6-trinitrophenyl)-l-naphthylamine (“ cc-hexyl ”) has been re~ommended.~~ The potassium salt23 G.N. Mitra and S. S. G. Sircar, J. Indian Chem. SOC., 1955, 32, 435.23 C. V. Banks and D. T. Hooker, Analyt. Chem., 1956, 28, 79; cf. R. C. Voter and24 E. S. Przkeval’skii, V. I. Shlenskaya, and N. F. Ogarkova, R e f . Zhur., Khim.,25 N . C. Sogani and S. C. Bhattacharya, Analyt. Chew., 1956, 28, 81.26 S. K. Datta, 2. analyt. Chem., 1955, 148, 259.27 S. K. Datta and G. Banerjee, AnaZyt. Chim. Acta, 1955, 13, 23.28 G. Banerjee, Naturwiss., 1955, 42, 417; cf.idem, 2. analyt. C h e w , 1955, 147,C. V. Banks, ibid., 1949, 21, 1320.1055, Abstr. No. 40,395.404, 409.G. S. Desmukh and J . Xavier, Bull. Chem. SOC. Japan, 1955, 28, 233.30 S. K. Datta, 2. analyt. Chem., 1955, 148, 267.31 G. Banerjee, ibid., 147, 348.32 W. Geilmann, H. Bode, and E. Kunkel, ibid., 148, 161.3a K . Toei, J . Chem. SOC. Japan, 1955, 76, 106336 ANALYTICAL CHEMISTRY.is considerably less soluble than that of dipicrylamine. Excess of sodiumor magnesium (25 : 1) and calcium (5 : 1) is without effect.Sodium has been determined gravimetrically by precipitation withmagnesium 1-naphthylamine-8-sulphonate from an ethanol-water medium.=A bromometric procedure for completing the determination has also beendeveloped.There is no information available as to interferences.Colorimetric.-Various 2 : 3 : 7-trihydroxy-6-fluorone derivatives whensubstituted in the 9-position have been found to give intense colours withtin(rv) and antimony(m) 35 and these reactions have been made the basisof colorimetric determinations. Tin(1v) is separated from antimony(II1) bydistillat ion.Oxalyldihydrazide has been proposed as a highly sensitive reagent forthe colorimetric determination of copper(r1) .36Iron(m) may be determined spectrophotometrically by allowing it toreact with 4-amino4’-methoxydiphenylamine (Variamine-blue) ; 37 a blue-violet meriquinoid compound is formed. There are few interferences.The method gives satisfactory results when applied to the determination ofiron in lead-antimony alloys.Zehner and Sweet 38 recommend 5-sulpho-anthranilic acid; a stable colour is formed with iron(II1) and there are fewinterferences. 4 : 7-Dihydroxy-1 : 10-phenanthroline has been found to besuitable for the determination of iron(I1) in alkaline solution.39, Iron(Ir1) isreduced by means of sodium dithionite (hydrosulphite).Trimethylaurincarboxylic acid (“ trimethyl-aluminon ”) has been pro-posed as a colorimetric reagent to replace a l ~ m i n o n . ~ ~ Ions (e.g., aluminium)which give colour reactions with aluminon behave in the same way with thenew reagent, but the colours are more intense.Peach 41 has used 3-methoxy-5-nitrosophenol for the colorimetricdetermination of iron(m) and cobalt. The complex of the latter is water-insoluble and is extracted with suitable organic solvents.The new reagentis claimed to have advantages over existing reagents for these metals.p-Mercaptopropionic acid has been proposed for the colorimetric deter-mination of 2-5-20 p.p.m. of cobalt.42 A deep green colour is produced;nickel and copper do not interfere.Osmium(v1) has been determined colorinietrically with l-naphthylamine-3 : 5 : 7-trisulphonic acid as reagent.43Clinch recommends 1-(2-arsonophenylazo)-2-naphtho1-3 : 6-disulphonicacid (APANS) for the colorimetric determination of thorium. He hasapplied the method to the analysis of monazite, thorium first being separatedby precipitation as the oxalate.The reaction is extremely sensitive.34 R. M. Dranitskaya, Ref.Zhur., Khim., 1955, Abstr. No. 5,779.35 V. A. Nazarenko and N . V. Lebedeva, Zhur. analif. Khim., 1955, 10, 289.36 G. Gran, Analyt. Chim. Actn, 1956, 14, 150.37 L. Erdey and F. Szabadvary, Acta Chim. Hung., 1955, 6, 131.38 J . M. Zehner and T. R. Sweet, Analyt. Chem., 1956, 28, 198.39 A. A. Schilt, G. F. Smith, and A. Heimbuch, ibid., p. 809.40 L. &I. Kul’herg and L. A. Molot, Ukrain. khim. Zhur., 1955, 21, 250.4 1 S. M. Peach, Analyst, 1956, 81, 371.43 H. C. Wingfield and J. H. Yoe, Aiialyt. Chim. Acfa, 1956, 14, 446.44 J . Clinch, ibid., p. 164.E. Lyons, Analyt. Chem., 1955, 27, 1813BELCHER, SHERIDAN, STEPHEN, AND WEST. 337A new method for the colorimetric determination of borate has beende~cribed.~~ When ferric sulphate and iodine solutions are added to an acidsolution containing polyvinyl alcohol and borate, a blue colour is obtained.The method is of interest in that most other colorimetric methods for boraterequire a concentrated sulphunc acid medium.Grob and Yoe46 haveproposed two new very sensitive reagents, 5-benzamido-6’-chloro-1 : 1’-di-anthrimide and 5-$-toluidino-l : 1‘-dianthrimide. Boron in fruit-tree leavesand lucerne was determined by decomposing the sample with sulphuric acidand then distilling as methyl borate.For the determination of chromate, o-aminophenyldithiocarbamic acidhas been proposed; 47 0-1-1.0 yg. of chromate per ml. may be determined.Svach and Zyka 48 determine nitrite colorimetrically by its reactionwith 2 : 5-diamino-7-ethoxyacridine ( I ‘ Rivanol ”) ; a red complex is formedin the presence of dilute hydrochloric acid.Stephen 49 has reviewed the colorimetric reagents which have beenThe accuracy is within &0.001 pg.proposed during the last few years.R.B.Inorganic Qualitative AnalysisIn last year’s Report, mention was made of the increasing use of thio-acetamide in place of hydrogen sulphide and ammonium sulphide in schemesof qualitative inorganic analysis. Criticism has been made of the in-discriminate use of thioacetamide. For example, Bon has commentedadversely on the paper by Bloemendal and Veerkarn~,~~ recommending thereplacement of H,S and (NH,),S, by thioacetamide. The latter authors,however, have answered these criticisms inIn the Fisher Award Address for 1956, Swift and Butler 53 discuss theprecipitation of sulphides from homogeneous solution by thioacetamide.Measurements have been made of the rate of hydrolysis of thioacetamideand of the Precipitation of lead sulphide by thioacetamide.These studiesprovide a basis for the prediction of the optimum conditions for the use ofthioacetamide in the precipitation and separation of metals as sulphides.It is clear from this work that the assumption that thioacetamide hydrolysesrapidly and completely in hot acid solution and can replace hydrogensulphide without modification of procedure is by no means true.have described a new scheme of qualitative analysisinvolving the use of thio-salts. The present scheme is a modification of theiroriginal one. Briefly, the metals are precipitated with a 1N-solution ofsodium sulphide instead of yellow ammonium sulphide.Calcium andstrontium are precipitated along with the sulphides and hydroxides of the45 R. F. Muraca and E. S. Jacobs, Chemist-Analyst, 1955, 44, 14.46 R. L. Grob and J . H. Yoe. Analyt. Chim. Acta, 1956, 14, 253.4 7 E. Gagliardi and W. Haas, 2. anal-vt. Chew.. 1955, 147, 321.4 s M. Svach and J. Zyka, ibid., 148, 1.49 W. I. Stephen, Ind. Chem. Mfr., 1955, 31, 622; 32, 38.50 W. F. Bon, Chem. Weekhlad, 1955, 51, 677.51 H. Bloemendal and T. A. Veerkamp, ibid., 1953, 49, 147.62 Idem, ibid., 1955, 51, 943.6s E. H. Swift and E. A. Butler, Analyt. Chem., 1956, 28, 146.51 1. K. Taimi and (>. E. S. Salarin, Analyt. Chim. Ada, 1055, 13, 205.Indian worker338 ANALYTICAL CHEMISTRY.Group 111 and I V cations by mixing the sodium sulphide reagent withsodium carbonate.Cerium and thorium are not separated but are testedfor separately within the iron group. Thallium is precipitated as the iodidewith the copper group by the addition of potassium iodide. A subsequentpaper 55 details the group separations of the common cations by formationof sulphides, hydroxides, and thio-salts by using a 1N-solution of sodiumsulphide. The subsequent separation and identification of the individualcations follow the more conventional analytical procedures. The sameworkers 56 have proposed a scheme for the qualitative analysis of the con-stituents of insoluble residues obtained after initial treatment of the sample.A list of likely substances affected and unaffected by various chemicaltreatments is given.A qualitative scheme has been described 57 for the detection of tracesof heavy metals in organic materials, in particular, fibres and syntheticresins. The material is destroyed by oxidation with nitric acid in a sealedtube (Carius’s method).The resulting solution is divided into three partsand colorimetric micro-tests are applied after extraction or volatilisation ofparticular elements from the solutions.Belcher, Farr, and Randles 58 have made certain observations on theprecipitation of Group I1 metals in qualitative analysis. After the separ-ation of Group I metals the filtrate is treated with a 6% solution of hydrogenperoxide and is warmed to reduce permanganate and dichromate ions.Arsenic pentasulphide is first precipitated by making the solution 6~ withrespect to hydrochloric acid and passing hydrogen sulphide into the solution.The remaining Group I1 cations are precipitated at an acidity of 0 .5 ~ withrespect to hydrochloric acid. The Group I1 sulphides are separated intothe A and B sub-groups by using Holness and Trewick’s lithium hydroxidereagent. The hot solution of Group IIB sulphides is poured into twice itsvolume of concentrated hydrochloric acid, and the sulphides of arsenic arefiltered off. The filtrate is cooled and diluted with an equal volume ofwater; hydrogen sulphide is passed into the solution and the antimonysulphide which is precipitated is filtered off.The filtrate is treated with anequal volume of 2~-aqueous ammonia, hydrogen sulphide is passed, and thestannic sulphide is then precipitated.Certain surface-active substances can prevent co-precipitation of ionswith sulphide precipitates. An investigation of this effect has been madeon the co-precipitation of thallium with arsenious sulphide. 59 The mosteflective substances are brilliant-green, malachite-green, and neutral-red.-4 scheme has been given for the qualitative analysis of cations without theuse of hydrogen sulphide.GO The cations are divided into five groups onthe basis of the solubilities of the chlorides, sulphates, basic salts, hydroxides,and ammonia complexes. The cations within the groups are detected inmost cases by fractional reactions.55 I.K. Taimi and G. B. S. Salaria, Ar,n.lyt. Chim. A d a , 1955, 13, 513.56 Idem, ibid., 1956, 14, 4.5 7 M. R. Lardera and A. Mori, Ann. Chim. (Italy), 1955, 45, 869.5* R. Belcher, J. P. G. Farr, and J. E. B. Randles, Analyt. China. Acta, 1955,13, 518.59 N. A. Rudnev, Zhur. analit. Khim., 1955, 10, 217.6O $5. Ya. Schngiderman, Izvest. Kievsk. Politekhn. In.st., 1954, 14, 140BELCHEK, SHEKIDAN, STEPHEN, AND WEST. 339The V:eisz ring-oven technique has been used by Blackman tjl for theseparation and identification of molybdenum and tungsten present in theform of molybdate and tungstate ions in the test solution. Stephen 62 hasextended the ring colorimetric procedures described by Weisz to includealuminium, beryllium magnesium, potassium cadmium, and zinc.Con-ventional organic reagents are used to develop the ring zones. Stephen 63has also described a combination of electrographic analysis and the ring-oven techniques which enables the rapid qualitative analysis of severalalloys to be carried out without apparent destruction of the sample. Themethod can also be used for the semi-quantitative analysis of a few simplealloys. Nall and Scholey describe a similar procedure for the testingand sorting of alloy steels. Their method is particularly suited for use insemi-skilled hands ; the entire apparatus and reagents are portable, thusfacilitating the testing of stored alloys.Weisz G5 has made an interesting study of the reactions suitable for theidentification of chloride, bromide, iodide, and thiocyanate when present inany combination of the four anions.Adsorption reactions have found application in qualitative analysis.66Thus, the desorption of a dye adsorbed on a colloidal solution of a silverhalide by addition of a halide solution can be used to detect traces of iodidein the presence of very large amounts of chloride and bromide.Chloride,bromide, and thiocyanate ions can also be detected, and the method can beextended to include pseudo-adsorption reactions given by sulphate andfluoride ions, and adsorption reactions of phosphate, tungstate, molybdate,and benzoate ions.The usual quota of new qualitative tests has been published during theyear. A new aluminium-type reagent has been proposed for the detectionof aluminium, called alumocresone (trimethylaurintricarboxylic acid).67The colour reactions are similar to those given by aluminon but show agreater intensity. The reagent can also be used for quantitative colorimetricanalyses. Derivatives of thiourea have been examined for use in the detec-tion of bismuth.68 Of the numerous reagents tested, the most sensitive isdi-o-tolylthiourea which forms a yellow complex with bismuth, the intensityof which is about ten times greater than that of the unsubstituted reagent.The reaction between lithium and " thorin " [2-(hydroxy-3 : 6-disulpho-l-naphthy1azo)benzenearsonic acid] has been studied.69 -4t pH 13.5, thereagent combines with lithium in the ratio 1 : 1. The complex is veryweak and does not constitute a very sensitive test for lithium.SimilarL. C. F. Blackman, Mikrochim. Acta, 1956, 1366.62 W. I. Stephen, ibid., p. 1540.ti3 Idem, ibid., p. 1531.+u W. R. Nall and R. Scholey, Metallurgia, 1956, 54, 97.6 5 H. Weisz, Mikrochim. Ada, 1956, 1225.L. M. Kul'berg and I. N. Bulankhe, Uch. Zap. Saratovsk. Univ., 1954, 34,6 7 L. M. Kul'berg and L. A. Molot, Ukrain. khim. Zhur., 1955, 21, 256.68 M. P. Makukha, Sbornik Ref. Nauch. Rabot Teor. Kaf. L'vov Med. Inst., 1954,ciB L. P. Adamovich and T. T. Alekseeva, Uch. Zap. Khar'kov Unirr., 1954. 54;154.94.Trudy Khim. Fak. i Nauch. Issledovntel. I n s t . Khim., 12, 209340 ANALYTICAL CHEMISTRY.studies have been made with beryllium 70 and thorium.71 With beryllium,the constituents react at pH 12.5 in the ratio of 2 : 3.The complex has aformation constant of 4.5 x With thorium, the reaction occurs inthe ratio of 1 : 2 at an optimum pH of 1-65. The formation constant isWest and McCoy 73 describe a new test for gold involving the extractionof chloroauric acid into n-butanol and treating this solution with a-naphthyl-amine. The resulting intense violet colour can be used to detect 1 pg. ofgold. Sen and West 73 detect 0-5 pg. of silver at a concentration of 10 p.p.m.using test papers saturated with the solution obtained by shaking a suspen-sion of nickel dimethylglyoxime with a solution of potassium cyanide. Ontreatment with a neutral silver solution, the test paper becomes red. Feigland Goldstein 74 use the p-nitrophenylhydrazone of diacetyl mono-oxime as aspecific reagent for the detection of cobalt.A violet complex is formed withas little as 0.5 pg. of cobalt at a dilution of 1 in 500,000.New colour adsorption reactions are described for magnesium.75 Theadsorption of dyes on magnesium hydroxide depends largely on the molecularweight of the adsorbed substance and the ageing of the precipitate. Thestability of the colour is increased by the presence of lead compounds,particularly sodium plumbite.A convenient test for cadmium 76 involves heating its neutral solutionwith a saturated solution of sodium thiosulphate, and adding hydrogenperoxide dropwise to the cooled solution. A yellow precipitate of cadmiumsulphide is formed with 2 pg. of cadmium in one drop of solution.Zinc 77can be detected in amounts of 1 pg. per 2 ml. of test solution by meansof the yellow colour formed on adding potassium ferrocyanide to an acidsolution of zinc containing methyl-violet. The reaction can also be usedquantitatively. A blue complex is formed when the red solution of tetra-methyldiaminodiphenylantipyrinylmethanol and ammonium thiocyanate isadded to a solution containing zinc ions.78 The reaction serves to identify2-3 pg. of zinc per ml. of solution. A new specific test is described forcopper(1r) which forms an intense red complex with 5 : 7-dihydroxy-4-methylcoumarin in ammoniacal solution. 79 The complex can be extractedinto organic solvents, The sensitivity is not given. Tetrabromoresorufincan be used for the detection of tin.80 The red acid solution is reduced to agreen colour by tin(I1).SNADS [l : 6-dihydroxy-2-(4-sulpho-l-naphthyl-azo)naphthalene-3 : 6-disulphonic acid] forms coloured complexes withthorium and zirconium and can be used as a spot reagent (sensitivity7.9 x 109.7O L. P. Adamovich and R. S. Didenko, Trudy Khim. Fak. i Nauch. Issledovaiel. Inst.7l L. P. Adamovich and V. M. Rutman, ibid., p. 203; for refs. 69, 70, 71, see Analyt.72 P. W. West and T. C. McCoy, Analyt. Chem., 1955, 27, 1820.73 B. Sen and P. TV. West, Mikrochim. A d a , 1955, 979.74 F. Feigl and D. Goldstein, Analyst, 1966, 81, 709.75 V. I. Kuznetsov, Zhur. analit. Khim., 1956, 11, 81.7 5 L. G. Gein, Trudy Komissii Analit. Khim. Akad. Nauk, S.S.S.R., 1954, 5, 133.7 7 V. I. Kuznetsov and L.S. Kozyreva, ibid., p. 86.7 8 V. P. Zhivopistsev, Uch. Zap. Molotov Univ., 1954, 8, 43.79 A. OlrAC and J. Hor&k, Chem. Listy, 1965, 49, 1403.80 E. RuiiCka, ibid., p. 1729.Khiwt., 12, 195.Abstr., 1956, No. 2631, 2646, 2695BELCHER, SHERIDAN, STEPHEN, AND WEST. 3412-4 pg.) . The 7-nitroso-derivative gives coloured complexes withcerium@), and with cobalt and nickel in ammoniacal solution.81 Flaschkaand Sadek s2 describe a selective test for zirconium using catechol-violet andEDTA. A deep blue colour is formed at a pH of 4-65 with very dilutesolutions of zirconium. Zolotavin 83 describes a qualitative reaction forvanadium based on the interaction of a vanadyl solution with one of ammon-ium molybdate. A deep blue colour results.Vanadium(v) can be detectedby its catalytic action on the oxidation of guaiacol to the coloured o-quinone ;less than 5 pg. of vanadium can be detected.84 2-Mercaptoresorcinol hasbeen studied as a possible analytical reagent.85 The colours given withseveral inorganic ions are generally more intense than those given by pyro-gallol. Wingfield and Yoe use l-naphthylaniine-3 : 5 : '7-trisulphonicacid for the detection of osmium(v1). At pH 1.5, a violet complex is formed,the reaction being sensitive to 1 part of OS(VI) in 1.5 x lo7 parts of solution.Feigl and Stark 87 describe a new test for elementary sulphur. Whenfree sulphur is fused with benzoin, hydrogen sulphide is formed which canbe detected by conventional means. The limit of detection is 0.05 pg.;selenium does not interfere.Schneider 88 reviews methods for the detectionof sulphur and recommends the use of piperidine; a red colour is formeddown to 4 pg. of free sulphur.Llacer 89 has improved the specificity and sensitivity of the rhodizonatetests for barium and strontium. The brown-red spots are treated withdimethylamine hydrochloride, a change in colour to bright red indicatingbarium and a change to blue-violet indicating strontium. Calcium can beidentified by the formation of characteristic crystals when a solution ofrhodizonic and benzoic acids is added to a solution of calcium ions. Llaceralso describes a scheme for the separation and estimation of barium,strontium, calcium, and magnesium.Filter-paper impregnated with zirconium 4-($-dimethylaminophenylazo) -diphenylarsinate is used for the detection of fluoride ions : the colourchange of brown to red occurs with not less than 0.05 pg.of fluoride ion.Common cations and anions do not interfere with the detection of more than4 pg. of fluoride.The nitration product of phenarsazinic acid gives a characteristic redcolour in alkaline solution which provides the basis of a new method for thedetection of not less than 3 pg. of the nitrate The test is not at allspecific.81 S. K. Datta, 2. analyt. Chem., 1956, 149, 270.82 H. Flaschka and F. Sadek, ibid., 150, 339.H3 V. L. Zolotavin, Zhzrr. analit. Khim., 1955, 10, 189.2. Jarabin and B. CsiszAr, Magyar Kkm. Folydirat, 1956, 62, 173.85 V. M. Dziomko and A. I.Dherepakhin, Sbornik Statei Vses. Zaoch. Politekh. Inst.,8 6 H. C. Wingfield and J. H. Yoe, Analyt. Chim. Ada, 1956, 14, 446.87 F. Feigl and C. Stark, Analyt. Chem., 1955, 27, 1838.d9 A. J. Llacer, Mikrochinz. Acta, 1955, 921.90 K. Tsuji and M. Kageyama, J . Pharm. SOC. Japan, 1954, 74, 1184.9 1 R. Pietsch, Mikrochim. Ada, 1956, 1490.1955, 65.W. Schneider, Arch. Pharm., 1956, 289, 299342 ANALYTICAL CHEMISTRY.Inorganic Gravimetric AnalysisThe determination of the alkali metals continues to receive much atten-tion, and classical gravimetric procedures are generally preferred because oftheir accuracy. Thus the gravimetric determination of potassium has beenthe subject of several recent papers. Flaschkag2 has given full details ofthe procedure used for the quantitative precipitation of potassium tetra-phenylboron.He also describes the subsequent alternative to the gravi-metric finish, that is, the non-aqueous titration of the precipitate. This is,perhaps, the most satisfactory of the numerous titrimetric proceduresdescribed in the literature. Berkhout and Jongen 93 also describe the pre-cipitation of potassium with sodium tetraphenylboron. Barnard 94 hasgiven a comprehensive bibliography on the uses and applications of sodiumtetraphenylboron as a gravimetric reagent during 1949-1955. Sykes 95has reviewed the applications of sodium tetraphenylboron in analysis.Wendlandt 96 has studied the pyrolysis of ammonium and alkali-metaltetraphenylborates by using the thermobalance. The potassium, rubidium,and czsium salts decompose between 210" and 265" but the ammoniumsalt sublimes a t 130".The precipitant was prepared according to the direc-tions of Gloss and Olson,97 and Kohler,9* and all the precipitates were driedat room temperature for 24 hours before pyrolysis. Sporekgs describes asimple and rapid method for the determination of potassium in sea waterby use of sodium tetraphenylboron. The method has the advantage ofrequiring no pretreatment of the sample, and only potassium is precipitatedunder the conditions employed.Russian workers loo have given directions for the determination ofpotassium in natural salt deposits by precipitation and weighing as potassiumcaIcium nickelonitrite, K,Ca[Ni( NO,),]. The precipitate is allowed to ageover-night, and is finally dried at 130".The maximum error does not exceed0.2%. The composition of some difficultly soluble cobaltinitrites has alsobeen studied, and a micro-method has been proposed for the determinationof potassium.10l K,Na[Co(NO,),] is recommended as the weighing form for0.1-0.5 mg. amounts of potassium, and K,Ag[Co(NO,),] for amounts inthe range 0.01-0.1 mg.A new procedure is described for the quantitative determination ofstrontium as the secondary phosphate.lo2 The precipitation of SrHPO, isquantitative at pH 6. The precipitate is crystalline, an advantage overstrontium sulphate; it can be filtered off after standing for 1 hour, washed92 H. Flaschka, Chew&-Analyst, 1955, 44, 60.93 H. W. Berkhout and G.H. Jongen, Chem. Weekblad, 1955, 51, 607.R4 A. J. Barnard, jun., Chemist-Analyst, 1955, 44, 104.O 5 A. Sykes, I n d . Chem. Mfr., 1956, 32, 223.96 W. W. Wendlandt, Analyt. Chem., 1956, 28, 1001.97 G. H. Gloss and B. Olson, Chenzist-Analyst, 1954, 43, 70.98 M. Kohler, 2. analyt. Chem., 1953, 138, 9.99 K. F. Sporek, Analyst, 1956, 81, 540.loo G. P. Alexsandrov and M. D. Lyntaya, Uhvain khim. Z h w . , 1956, 21, 518.lol I. M. Korenman, F. R. Sheyanova, and 2. I. Glazunova, Priirzen. Mech. Atom.I o 2 G. Denk, R. Dunkel, and C . Keller, Z . a.na2vt. Chem., 19.56, 152, 31.z'Ana1. Khitn. M., I z d . Akad. Nauk S.S.S.R., 1955, 29BELCHER, SHERIDAN, STEPHEN, AND WEST. 343with a little cold water, and dried at 120-130" for 1 hour. The precipitatecan be ignited to pyrophosphate.The perennial question of the composition of barium sulphate precipitatesagain receives attention.Sgzganova lo3 has studied the effect of a verylarge excess of ferric chloride on the precipitation of barium sulphate. Bestresults are obtained by precipitation at 80" from a solution of 1.2 X 1 O A 2 ~ -hydrochloric acid. Bogan and Moyer have continued the study ofageing in barium chloride solutions as a factor influencing the particle sizeof precipitates of barium sulphate. A large increase in particle size ofbarium sulphate crystals occurs when an aged solution (1-6 days) or afreshly filtered solution of barium chloride is used. Popov lo5 has discussedthe difficulties of removing co-precipitated lead sulphate from bariumsulphate.Bagshawe and Pill lo6 have described an improved barium sulphatemethod for the determination of sulphur in steels, particularly alloychromium steels for which the conventional B.S.method is unsatisfactory.The important stage is the removal of excess of nitrate ions by hydroxyl-amine instead of by baking. The method is precise to within 0.002%.Barium carbonate is almost quantitatively precipitated by passingcarbon dioxide into an ammoniacal solution of barium ions.lo7 The additionof 20% of ethanol makes filtration of the dense precipitate an easy matter.A survey has been given lo8 of methods available for precipitation fromhomogeneous solution. The applications of these methods to gravimetricanalysis are described, and their advantages critically discussed.Russianworkers log have made a comprehensive study of generant reagents used inthe determination of the alkaline-earth metals. Barium can be determinedin the presence of the usual interfering ions, for example, nitrate and fluoride,without detrimental effects by using dimethyl sulphate as reagent. Theprocedure can be modified to enable the determination of barium to besuccessfully carried out in the presence of calcium and strontium.Numerous isolated gravimetric determinations have been describedduring the year, and of these, the following deserve mention. A procedureis described for the gravimetric determination of small amounts of telluriumin sulphur.l1° The free element is precipitated from solution by reductionwith hydrazine and sulphur dioxide.Magnesium (12-160 mg.) is precipit-ated by a three-fold excess of sodium fluoride.lll The precipitate of sodiummagnesium fluoride is centrifuged off, washed with ethanol (70%), and driedat 130". The error is &0.3%. Cadmium 112 can be determined in thepresence of considerable amounts of zinc by precipitation with thioureaFusion with sodium carbonate is recommended.lo3 0. P. Syzganova, Trudy Kazansk. Khim.-Teknol. In-?'a, 1952, 139.lo* E. J. Bogan and H. V. Moyer, Analyt. Chem., 1956, 28, 473.lo5 nil. A. Popov, Zavodskaya Lab., 1955, 21, 1430.lo6 B. Bagshawe and A. L. Pill, Analyst, 1955, 80, 796.lo' H. Teicher, Analyt. Chem., 1955, 27, 1416.lo* J. Agterdenbos, Chem. Weekblad, 1955, 51, 57 1.loQ A.P. Terent'ev, E. G. Rukhadze, and K. I. Litvin, Zhuv. atzalit. Khim., 1956,110 A. Aarenmae and G. 0. Assarsson, Analyt. Chenz., 1955, 27, 1155.ll1 Sh. T. Talipov and A. T. Tashkhodzhayer, Trudy Sredneaziat. Goszidarst. Univ.11* 0. A. Songina, Uch. Za?. Kazakh. Univ., 1954, 18, 58.11, 55.(Tashkent), Khim. Nauk. 1954, 55, 141344 ANALYTICAL CHEMISTRY.and Reinecke's salt. The procedure is empirical and is accurate to &l%.A new weighing form for palladium(I1) and rnercury(I1) is bisethylenediamine-palladium(I1) tetraiodomercurate, Pd(en),HgI4.ll3 The precipitate can bedried at 115'. Most common anions do not interfere with the determin-ation. Milligram amounts of germanium are determined by precipitationof acridine m~lybdogermanate.~~~ No empirical factor need be applied.Inorganic gravimetric analysis has been reviewed by Beamish andWestland 115 in the Analytical Chemistry Annual Review of FundamentalDevelopments in Analysis.Goyanes 116 has reviewed the applications ofthermogravimetric analysis and has described the various types of thermo-balances.A new procedure has been given for the determination of arsenic as thepentasulphide. 117 The precipitate obtained on passing hydrogen sulphideinto an arsenic solution is dissolved in the minimum amount of nearlycolourless ammonium sulphide ; oxidation of As(@ to As(v) occurs, andon adding hydrochloric acid, arsenic pentasulphide and sulphur are pre-cipitated. Washing with carbon disulphide removes the sulphur from theprecipitate, which is then dried at 105" and weighed. Sarudills has in-vestigated Vortmann and Metzl's classical method for the separation ofantimony and tin in order to assess its usefulness as a quantitative method.The method is reliable and gives a sharp separation independently of theamount of either metal present.Several Iiew gravimetric procedures have been developed using 8-hydr-oxyquinoline (oxine) as precipitant. In the presence of EDTA, uranium 119is quantitatively precipitated from a solution containing thorium,zirconium, rare-earth cations, phosphorus, and vanadium. The pre-paration of beryllium 8-hydroxyquinoline dihydrate and the gravimetricdetermination of beryllium in the form of this complex have been studiedby Motojima.120 The method can be used for the separation and determin-ation of beryllium in the presence of aluminium, iron, copper, and zinc.121Wendlandt 122 has given the thermogravimetric data of the pyrolysis of thecomplexes of 8-hydroxyquinoline and its 5 : 7-dichloro- and 5 : 7-dibromo-derivative with scandium, thorium, and uranium.Hahn and Baginski 123 have overcome the difficulties in determiningzirconium with mandelic acid.If the precipitation is carried out at atemperature of 85-90' from a solution not less than 5 M in hydrochloric acid,the zirconium tetramandelate can be filtered off, washed, dried, and weighedas such without the need of a correction factor.113 G. W. Watt, D. M. Sowards, and R. E. McCarley, Analyt. Chetn., 1956, 28, 556.114 P. R.Subbaraman, J . Sci. Ind. Res. India. 1955, B, 14, 640.115 I?. E. Beamish and A. D. Westland, Analyt. Chem., 1956, 28, 694.116 C. B. Goyanes, Inf. Quim. Anal., 1955, 9, 159.117 K. I. Kal'pchiev, Zhur. analit. Khim., 1955, 10, 334.11* I. Sarudi, 2. analyt. Chenz., 1955, 148, 21.119 R. N. Sen Sarma and A. I<. Mallik, ibid., p. 179.120 K. Motojima, J . Chenz. SOC. Japan, Pure Chem. Sec., 1956, 77, 95.lZ1 Idem, ibid., p. 100.W. W. Wendlandt, Analyt. Chem., 1956, 28, 499.R. B. Hahn and E. S. Baginski, Analyt. Chinz. Acta, 1956, 14, 45BELCHER, SHERIDAN, STEPHEN, AND WEST. 346Inorganic Titrimetric AnalysisIndicators.-Few acid-base indicators have been recommended this year,but mention should be made of the following. Four new indicators havebeen synthesised 124 by introducing chlorine or bromine into the molecule oftropzeolin-00.These substances give a colour change similar to that oftropEolin but at a lower pH. They are effective in the range A . 0 3 ~ -hydrochloric acid. Mikhailov 125 gives examples of mixed one-colouracid-alkali indicators which show a colourless pH range between twocoloured ranges. Malowan prefers to use alizarin in place of phenol-phthalein to indicate when an excess of alkali is present in the solutionbefore distillation of ammonia in the Kjeldahl method. Large amounts ofiron do not make the blue-violet colour of the solution less easily seen.Phenol-red screened with methylene-blue gives a sharp colour change fromgreen in acid to violet in alkali; 12' a blue intermediate colour appears atpH 7.3, regardless of the direction of the titration.Pungor and Schulek 12*suggest that the colour changes which occur when fi-ethoxychrysoidine isused as an acid-base indicator arise by formation of quaternary ammoniumbases. Dangl lZ9 lists 23 substances which fluoresce in aqueous solutionunder ultraviolet light with colour intensities depending on the pH. Thesesubstances are useful for titrating strongly coloured solutions. The pHrange 0-14 is covered and the colour changes are given.Potassium rhodizonate is used as an argentimetric indicator in thetitration of bromide, iodide, and cyanide.130 It can also be used in theVolhard titration of silver with thiocyanate. Accuracy and precision aregood. Mixed adsorption indicators are recommended 131 for the titrationof silver with bromide. Good results are obtained in 0~01-0~001N-solutionswith rhodamine-6G and methylene-blue, rhodamine-6G and fluorescein, andmethylene-blue and fluorescein. Titan-yellow 132 behaves reversibly as anadsorption indicator in the titration of chloride and bromide with mercurousnitrate.When p-ethoxychrysoidine is used as an adsorption indicator forthe argentimetric determination of iodide,l= the indicator undergoes anacid-base change at the end-point.When used as a redox indicator, fi-ethoxychrysoidine is oxidised to anazoxy-cornpound.l= The redox potential, E,, is 0.76 volt. Metanil-yellow and Astral-blue-G have been used as indicators in cerimetrictitrations : 135 the first behaves irreversibly and changes from carmine-redto greenish-blue on oxidation; the second is reversible, but the colourlZ4 V.I. Kuznetsov and G. N. Kosheleva, Zhur. analit. Khim., 1956, 11, 208.lZ6 G. I. Mikhailov, ibid., 1955, 10, 382.lZu L. S. Malowan, Chemist-Analyst, 1955, 44, 75.lZ7 M. R. Verma and V. M. Buchar, ibid., p. 73.lZ8 E. Pungor and E. Schulek, 2. analyt. Chew., 1956, 150, 161.130 J . P. Mehlig, Chemist-Analyst, 1955, 44, 87.131 I. N. Bulanzhe and G. A. Mel'nik, Sbornik Trudov. Kievsk. Tekhnol. Inst. Legk.132 V. A. Vorobeichikov, Zavodskaya Lab., 1956, 22, 645.133 E. Pungor and E. Schulek, 2. unalyt. Chm., 1956, 150, 166.la4 Idem. ibid., p. 161.la6 J. Bop& and 2. Ngdler, Magyar Kdm. FoZydtrat, 1966, 61, 372.F. Dangl, Prakt. Chenz., 1955, 6, 249.Prom., 1954, 74346 ANALYTICAL CHEMISTRY.change is less intense and less contrasting.The E, value is about 0.97 volt.Xylene-blue-VS and setoglaucin-0 behave similarly to Astral-blue-G.Phenoxazone 136 is a useful indicator for titrations involving the use ofstrong reducing agents : the red oxidised form changes sharply to blue atan E, value of 0.6 volt; both forms of the indicator are stable in solution.Gibson and White use triphenylmethylarsonium iodide as indicator inthe titration of arsenite and thiosulphate with 0.1 and 0-Olhr-iodine, and inthe reverse titrations. The end-point is marked by the formation or decom-position of the yellow-brown tri-iodide complex of the indicator extractedinto a layer of chloroform or carbon tetrachloride.Presumably the indicatorreaction is more sensitive and easily seen than that of direct observation ofthe violet iodine colour in the organic layer.Most of the recent work on indicators has been concerned with thedevelopment of new indicators for complexometric titrations. The ever-increasing applications of the complexometric methods makes this work ofprime importance, for without suitable indicators, the methods cannot beused with any great selectivity. West 138 has reviewed the uses of theindicators available for complexometric titrations and covers the literatureto the early part of 1956. Suk and Malat 139 describe the properties andapplications of catechol-violet in chelatometry. This important indicatorfinds further applications in the titration of bismuth and thorium in thepresence of iron and mercury,140 and in the determination of thorium in gasmantles, in solutions used for their preparation, and in optical g1a~ses.l~~Pyrogallolcarboxylic acid functions satisfactorily as indicator in thecomplexometric determination of calcium : 142 at the end-point, the violetcolour disappears ; magnesium does not interfere.For other cations theindistinct colour change makes direct titration inadvisable and a back-titration procedure is recommended. Pyrogallolsulphonphthalein (pyro-gallol-red) enables bismuth to be determined in acid solution in the presenceof a large number of common cati0ns.1~3 The solution of bismuth is adjustedto pH 2-3 and is titrated with EDTA in the presence of the indicator untilthe colour change of red to orange-yellow is observed.Small amounts ofnickel and cobalt can be determined in weakly alkaline solution by usingthis indicator, the colour change at the end-point being blue to red.Condensation of iminodiacetic acid and fluorescein gives a product oftrivial name " Calcein " which is superior to murexide as indicator in thecomplexometric titration of calcium.lU Magnesium can be present inamounts 30-40 times that of calcium without affecting the sharpness ofthe end-point. The titration is carried out at pH 1 2 ; the colour change isyellow-green to brown. A sharp stable colour change from wine-red to136 S. Musha and T. Kitagawa, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76,13' N.A. Gibson and R. A. White, Analyt. Chim. A d a , 1955, 13, 546.138 T. S. West, Ind. Chem. Mfr.. 1956, 32, 82, 128.13B V. Suk and M. MalAt, Chemist-AnaZyst, 1956, 45, 30.140 J. Cifka, M. MalAt, and V. Suk, Coll. Czech. Chem. Comni., 1956, 21, 412.141 M. MalBt, J. Pelikan, and V. Suk, Chemist-Analyst, 1956, 45, 61.142 M. Kovaiik and M. MouEka, 2. analyt. Chern., 1956, 150, 416.148 V. Suk, M. Makit, and A. JeniEkovA, Coll. Czech. Chem. Comm., 1966, 21, 418.144 H. Diehl and J. L. Ellingboe. Analyt. Chem.. 1956, 28, 882.1289BELCHER, SHERIDAN, STEPHEN, AND WEST. 347pure blue is obtained by using 2-hydroxy-l-(2-hydroxy-4-sulpho-l-naphthyl-azo)-3-naphthoic acid as indicator in the complexometric titration of calciumat pH 12-14; 145 magnesium does not interfere.Cheng 146 has examineda solution of the zinc complex of Eriochrome blue-black-R as an indicatorin chelatometry and finds it superior to other solutions of this and similardyes. He assigns the trivial name " Zinchronie R " to this indicator. Thesolution is stable for prolonged periods and finds use particularly in thedetermination of water hardness.Saj6 14' describes a novel method of indication in complexometrictitrations based on the replacement of vanadium(v) in its complex withEDTA by most cations. The liberated vanadium is detected by usingdiphenylcarbazide or diphenylcarbazone. The method is applied in the pHrange 46-66 and consequently only metals which form chelates withEDTA in this pH range can be determined.Wehber 14* uses the pale brown decomposition product of Bindschedler ' sgreen as redox indicator in the complexometric determination of iron(II1)salts with EDTA at pH 2-5-36 The indicator gives a green colour withoxidising agents and at the end-point it changes sharply to orange.Theindicator has also been used in the indirect determination of chromium(rr1) 149with EDTA.Flaschka and Abdine 1 5 * 9 151 have studied the use of l-(%pyridylazo)-2-naphthol (PAN), introduced by Cheng and Bray,152 as indicator in complexo-metric micro-titrations. The excess of EDTA used to complex the metalsis back-titrated with copper(I1). A subsequent paper 153 details the use ofthe copper-PAN complex as indicator in titrations with EDTA in acidicmedia, and in ammoniacal solutions.Zinc, cadmium, lead, indium, gallium,vanadium, nickel, cobalt, calcium, magnesium , and manganese can all bereadily determined. Cheng describes the titration of scandium and ofindium 155 with EDTA, using PAN as indicator.1 : 8-dihydroxy-2- (9-sulp hophenylazo) napht halene-3 : 6-disulphonic acid (SPADNS) as indicator in the direct complexometricdetermination of zirconium with EDTA. The zirconium-SPADNScomplex is crimson-pink, and at the end-point of the titration the colourchanges to orange red. The thorium-SPADNS lake can also be used in thedetermination of thorium with EDTA.15' Datta 15* has carried outsimilar studies using dyes derived from 1 : 8-dihydroxy-2-(4-sulpho-l-naphthy1azo)naphthalene-3 : 6-disulphonic acid (SNADNS).Certain ofBanerj ee 156 uses145 J. Patton and W. Reeder, AnaZyt. Chem., 1956, 1026.146 K. L. Cheng, Ckemist-AnaZyst, 1956, 45, 79.14' I. Saj6, Magyar KLm. FoZydirat, 1956, 62, 176.14* P. Wehber, 2. analyt. Chem., 1956, 149, 161.140 Idenz, ibid., 150, 186.150 H. Flaschka and H. Abdine, Cheinisf-Analyst, 1956, 45, 2.151 Idem, Mikrochim. Ada, 1956, 770.lS2 K. L. Cheng and R. H. Bray, AnaZyt. Chem., 1955, 27, 782.153 H. FIaschka and H. Abdine, ChemiskAnaZyst, 1956, 45, 58.lb4 K. L. Cheng and T. R. Williams, ibid., 1955, 44, 96.155 K. L. Cheng, Analyt. Chem., 1955, 27, 1582.lb6 G. Banerjee, 2. analyt. Chem., 1955, 147, 105.lS7 Idem, ibid., 148, 349.15* S. K. Datta, ibid., 1966, 149, 328348 ANALYTICAL CHEMISTRY.these substances give lakes with thorium, which facilitate its complexometricdetermination.Standardisation.-Singh and Singh 159 have recommenced diethylenetetra-ammonium sulphatocerate as a suitable oxidimetric standard.It is readilyprepared and shows no tendency to decompose. It has a very high equiv-alent weight (774.7) and has the formula (NH,*CH,*CH,*NH,)2Cl(S04)4,7H20.Singh and Singh use O.O2~-solutions of the substance in 2~-sulphuric acid,but make no mention of its solubility. In the Reporter's experience, it ispossible to dissolve only 20 g. of the substance in 1 1. of 2~-acid, whichrestricts the use of the reagent to O.O2~-solutions. Nevertheless, the reagentshould prove an extremely valuable one as no satisfactory primary standardcontaining cerium( 1v) has hitherto been recommended.Dipyridinezinc dithiocyanate [Zn(C,M,N),] (SCN), can be prepared in apure state.Because of its purity, stability, and high equivalent weight itis recommended as a standard for EDTA solutions.160Standard solutions of iodate, approximately 0 - 0 1 ~ and accurate to threesignificant figures, can be prepared by saturating distilled water withbarium iodate at constant temperature. Barium iodate monohydratecan be obtained in a very pure state. Saturation occurs within 1 hour at 25".Duval and co-workers 162 have continued the therniogravimetric studyof analytical standards. The substances examined include barium hydr-oxide, boric acid, arsenious oxide, potassium sulphate, and sodium tungstate.Sant 163 recommends arsenious oxide-an established standard-as aprimary standard for the iodometric determination of barium and lead afterprecipitation as the chromates.Ion-exchange resins have been used to prepare carbonate-free solutionsof strong bases 164 and of alkali-metal, alkaline-earth metal, and tetra-alkylammonium hydroxides 165 for use in titrimetry.Standard solutionsof nitric, sulphuric, and hydrochloric acids can be readily prepared by pass-ing aqueous solutions of known weights of the appropriate salts through acation exchange column and diluting the eluates to a known volume.lG6The upper limit of concentration recommended for solutions prepared in thisway is 0.25~.The classical acidimetric standard, sodium carbonate, has recently beenthe subject of much controversy.Balk and his co-workers 167 find that thevariation between six different commercial samples of sodium carbonate ofthe highest quality when checked against 1N-sulphuric acid as a referencestandard is less than 1 part in 1000. Because 01 uncertainties in the ignitiontemperature of sodium hydrogen carbonate to form sodium carbonate, doubthas been cast on the reliability of sodium carbonate as a primary standard.159 B. Singh and S. Singh, Analvt. Chem. Acta, 1956, 14, 109, 405.l60 B. BudeSinsk9, CoZZ. Czech. Chem. Comm., 1956, 21, 255.161 S. K. Yasuda and J. L. Lambert, Chemist-Analyst, 1956, 45, 50.lG2 C. Duval, C. Wadier, and Y . Servigne, AnaZyt. Chim. Acta, 1955, 13, 427.163 B. R. Sant, 2. analyt. Chenz., 1955, 148, 176.164 D. M.G. Armstrong, Claem. and Ind., 1055, 1405.165 E. Sandi, Magyar KLm. Folydirat, 1955, 61, 29.166 C. J. Keattch, Lab. Practice, 1056, 5, 208.167 E. W. Balis, L. B. Bronk, H. A. Liebliafsky, and H. G. Pfeiffer, Analyt. Chenz.,1955, 2'4, 1173BELCHER, SHERIDAN, STEPHEN, AND WEST. 349Desjobert and Petek,168 in fact, state that it is inadvisable to use ignitedsodium hydrogen carbonate as a reference standard and they recommendthe use of potassium carbonate obtained by ignition of potassium hydrogencarbonate. This has been accepted by chemical manufacturers in thiscountry, who supply reagents purified for volumetric standardisation. l 6 9The statement that sodium carbonate cannot be used as a working standardhas been refuted by the Analytical Chemists' Committee of ImperialChemical Industries Limited.170 In its experience accurate results can beobtained by using sodium carbonate prepared by heating the sesqui-carbonate to 270".Williams has reviewed the applications of primary standard substancesin micro-volumetric analy~is.17~Reagents.-Amongst the newer titrimetric reagents, ascorbic acid con-tinues to find use as a reducing titrant.Japanese workers 172 describe thedifferential titration of iron(II1) , copper(II), and vanadate. The last can betitrated directly with ascorbic acid, diphenylamine being used as indicator.Gopala Rao and Narayana Rao 173 give the best conditions for preparingstable solutions of ascorbic acid. In a subsequent paper,li4 the reductionof mercury(I1) chloride is described. Erdey and Svehla 175 use ascorbicacid for the determination of ferricyanides at pH 5-6.2 : 6-Dichloro-phenolindophenol can be used as indicator. Iridium(Iv), in the form ofits complex chloride, can be determined by reductometric titration withascorbic acid and diphenylamine as i n d i ~ a t 0 r . l ~ ~ Macdonald 177 hasreviewed the applications of ascorbic acid as a reductant in titrimetry.Erdey, Bodor, and Buzh 178 describe the rapid direct titration of vanadicacid with ascorbic acid using Variamine-blue as indicator ; an indirectprocedure involving iron@) can also be applied to the determination ofvanadium. 179Quinol solutions have been recommended as reductometric reagents.180The solutions are stable even at the low concentration of 0 . 0 0 1 ~ ~ and arereadily standardised by titration with dichromate.An excess of iron(m)does not interfere, since for some unknown reason it is not reduced by quinolunder the conditions of the determination.Solutions of cobalt(m) in dilute sulphuric acid have been investigated aspossible oxidising titrants for iron@) , cerium(II1) , arsenite, oxalate, peroxide,and f errocyanide.16* A. Desjobert and F. Petek, Analyt. Chim. Acta, 1956, 14, 19.lBS Hopkin and Williams Ltd., " P.V.S. Reagents for Volumetric Standardisation,"170 Chem. a i d Ind., 1956, 346.171 M. Williams, INd. Chem. Mfr., 1956, 32, 442, 492.17* C. Yoshimura and T. Fuzitani, J . Chem. SOC. Japan, Pure Chem. Sect., 1955,76,304.173 G. Gopala Rao and V.Narayana Rao, 2. analyt. Chem., 1955, 147, 338.174 G. Gopala Rao and U. Veereswara Rao, ibid., 1956, 150, 29.175 L. Erdey and G. Svehla, ibid., p. 407.176 N. K. Pshenitsw and I. V. Prokof'eva, Izvest. Sektora Platinydrug. blugorod.Metal., Inst. obshchei neorg. Khim., 1955, 176.17' A. Macdonald, Ind. Chem. Mfr., 1956, 32, 545.17* L. Erdey, E. Rodor, and I. BuzAs, Acta Chim. Acad. Sci. Hung., 1955, 7, 277.17D Idem, ibid., p. 287.l a l C . E. Briclier and L. J. Loeffler, Analyt. Chem., 1955, 27, 1419.1955, 7.V. Simon and J. Zyka. ColE. Czech. Chem. Comm.. 1956. 21. 327350 ANALYTICAL CH E MIISTRY.Methods.-Few acid-base methods have been reported during the year.RrandStetr la2 describes the acidimetric determination of hydrazine hydrate,but variable results are obtained as a result of decomposition of the hydrazine.Beryllium lS3 can be determined by acidimetric titration after neutralisationof the solution to phenolphthalein and addition of sodium fluoride.Inter-ference of common ions is prevented by addition of sodium tartrate. Rosen-thaler 184 has continued his studies of bromine-acidimetric methods. Hispresent paper describes the determination of phosphorous acid, hypo-phosphite, sulphurous acid, and thiourea. The sample is oxidised withbromine, and the liberated acid is titrated with standard alkali.Precipitation reactions continue to find use in titrimetric analysis. Theferrocyanide titration of cadmium 185f 186 and manganese 187y lS8 has beendescribed ; o-dianisidine, diphenylamine, and 3 : 3'-dimethylnaphthidineare used as indicators.A simple procedure is given for the titration of leadwith molybdate using diphenylcarbazone as indicator. la9Barium is determined by titration with sodium lauryl sulphate; lgo anexcess of the reagent is added and the barium salt is filtered off, the excessbeing determined by titration with a quaternary ammonium salt usingmethyl-yellow-chloroform as indicator. The procedure can also be usedfor the determination of ~u1phates.l~~Most of the literature on titrimetric analysis concerns coniplexometricand redox titrations. It is not practicable to consider all of these methods inany detail, nor indeed to mention all of them. Nevertheless, an attempt ismade in this Report to select the more important methods.The recentpublications concerning chelatometric titrations are concerned mainly withthe application of established procedures to particular problems, particularlyin the analysis of alloys, ores, natural salts, paints, pigments, etc. Fewcomprehensive reviews have appeared ; Flaschka cites 183 references inhis review of the use of complexones in analysis,lg2 and Yatsimirskii lg3 givesa review of the subject with 181 references. Comparable reviews have notappeared in English. The copper(I1)-EDTA system has been studied byBelcher, Gibbons, and West and by Wehber.lg5 The last worker usesVariamine-blue B as indicator, in the presence of an excess of thiocyanate.Milner and Edwards determine zirconium in its binary alloys with niobiumand tantalum by an indirect procedure; Fritz and Johnson Ig7 also describela* J.Brandgtetr, C'hcm. Zvesti, 1964, 8, 261.ls3 V. K. Zolotulihin, Trit@y Konzissii Anal. Khim. Akad. Nnuk, S.S.S.H.. l!Ki4, 5 ,l a 5 H. Basiliska, Wiadoin. Chem., 1953, 7, 284.la6 G. A . Segar, Analyst, 1956, 81, 65.187 I. Saj6, Magyar Kbm. Folydirat, 1955, 61, 196.188 K. L. Cheng, Analyt. Chem., 1955, 27, 1594.l a g T. 1;. Dubrovskaya and N. A. Fillipova, Zavodskaya Lab., 1955, 21, 523.lg0 J. I<. Gwilt, J . Appl. Chem., 1955, 5, 471.101 W. Davey and J. R. Gwilt, ibid., p. 474.192 H. Flaschka, Fortschi/. Chem. Forsch., 1955, 3, 253.193 K. 13. Yatsimirkii, Zavodskaya Lab., 1955, 21, 1149.194 K. Belcher, D. Gibbons, and T. S. West, Analyt.Chim. A d a , 1955, 13, 226.lQ5 P. Wehber, Mikrochim. Acta, 1955, 927; 2. analyt. Chem., 1956, 149, 244.196 G. W. C . Milner and J. W. Edwards, Analyt. Cham. Acta, 1955, 13, 230.1 8 7 J . S. Fritz and M. Johnson, AnnZyt. Chem., 1955, 27, 1653.224.L. Rosenthsler, Pharm. Acta Helv., 1955, 30, 332RELCHEK, SHERIIJAN, STEPHEN, AND WEST. 35 Ithe indirect determination of zirconium using bismuth in the back-titration.Iron can be determined at pH 1.7-3.0 by using Variamine-blue asindicator.lg8 Flaschka and Sadek 199 use bismuth nitrate and catechol-violet for the indirect complexometric determination of indium, gallium,iron, and thorium at pH 2-3. Takamoto 2oo uses the cobalt thiocyanate-acetone complex as indicator in the titration of cobalt(@ with EDTA.The method can be applied to the indirect determination of several heavymetals with EDTA.Brunisholz and Cahen 201 titrate the rare-earthcations with EDTA in slightly acid solution, using sodium alizarin-sulphonate and methylene-blue as indicator. The titration of nickel hasbeen examined; ter Haar and Bazen 202 find slight interference from cobaltat pH 2.8, but Flaschka and Puschel 203 carry out the titration at pH 2 at 0".Under these conditions the Ni-EDTA complex is stable and will notreact with bismuth ions used to titrate the excess of EDTA. Otherdeterminations of metals include that of aluminium in 205 nickel,magnesium, zinc, and manganese in the presence of titanium,?06 gallium,207gallium in flue dust ,208 calcium in nickel-base alloys,209 aluminium, lead,and zinc in bronze and brass,210 and magnesium in nodular cast-iron.211Eschmann and Brochon 212 determine phosphate by precipitation ofmagnesium ammonium phosphate at pH 9 with 2-aminoethanol; themagnesium in the precipitate is determined by titration with EDTA.Similarly, pyrophosphate 213 can be determined in the presence of ortho-and trimeta-phosphates by precipitating zinc pyrophosphate at pH 3.8-3.9and titrating the zinc with EDTA.Jankovits 214 suggests the use of triphosphoric acid as a complexingtitrant. The solution is stable for about 10 days but quantitative complex-formation takes place only in very dilute solutions.Calcium and magnesiumcan be titrated at pH 10-11 by using Eriochrome-black-T as indicator.Numerous titrimetric procedures involving redox processes have beendescribed.The titrimetric determination of iron(m) has been studied byseveral workers. Iron in the presence of copper and other interfering ionshas been determined by photochemical reduction with sodium ~ x a l a t e . ~ l ~ * 216Small amounts of iron(I1) are determined cerimetrically without interference19* L. Erdey and G. Rfidy, 2. analyt. Chern., 1956, 149, 250.loo H. Flaschka and F. Sadek, ibid., p. 345.200 S. Takamoto, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1339.201 G. Brunisholz and R. Cahen, Helv. Chim. Acta, 1956, 39, 324.202 K. ter Haar and J . Bazen, Analyt. Chim. Acta, 1956, 14, 409.%03 H. Flaschka and R. Puschel, 2. analyt. Chem., 1955, 147, 354.204 C.Elliot and J. W. Robinson, Analyt. Chim. A c f a , 1955, 13, 236.) 0 5 Idem, ibid.. p. 309.%06 B. M. Dobkina and E. I. 'Petrova, Zavodskaya Lab., 1956, 22, 525.~7 T. V. Cherkashina, ibid., p. 276.?08 J. Doleial, V. Patrovskq, 2. Sulcek, and J. Svasta, Chem. Listy, 1965, 49, 1517.zo9 V. E. Bukhtiarv, Zavodskaya Lab., 1955, 21, 1042.210 J. Kinnunen and B. Merikanto, Chemist-Analyst, 1955, 44, 75.%11 H. Green, J . Brit. Cast Iron Res. ASSOG., 1955, 6, 20.212 H. Eschmann and R. Brochon, Chemist-Analyst, 1956, 45, 38.T. Kato, Z. Hagiwara, and R. Shinozawa, Japan Analyst, 1955, 4, 486.$14 L. Jankovits, Acta Chim. Acad. Sci. Hung., 1956, 8, 355.%15 M. N. Sastri and L. Subbaraya Sarma, 2. anorg. Chem., 1955, 281, 221.216 M. N. Sastri and C.Kalidas, 2. analyt. Chew., 1956, 149, 181352 ANALYTICAL CHEMISTRY.from arsenic(II1) and antirnony(~~~).~l~ Sodium hypophosphite is proposedas a reductant for iron(II1) ; reduction to iron@) occurs on boiling the acidsolution ( 2 ~ ) for 15-20 minutes.218 The oxidation of iron(I1) in acid-freesolutions by permanganate has been studied.219 The mechanism of theaction of the Zimmermann-Reinhardt reagents has been studied. Boraxand sodium acetate are as effective in the titration of pure iron solutions,but in the analysis of iron ores, a mixture of sodium sulphate and potassiumfluoride is preferred.220In IN-sulphuric acid, uranium(v1) is rapidly reduced by ethanol whenexposed to sunlight or ultraviolet light. Standard sodium vanadate is usedto titrate the uranium(1v) since other oxidants react with the excess ofethanol.221 The uses of vanadium salts in titrimetry have been discussedin a recent review by Macdonald.222 Uranium(1v) can be oxidised touranium(v1) by alkaline iodine; the solution can be acidified, and theexcess of iodine determined by titration with t h i o s ~ l p h a t e . ~ ~ ~ In the pre-sence of telluric acid, manganese(1v) is stabilised in alkaline solution and aprocedure has been developed for the determination of manganese based onthis fact ; 224 the subsequent reductometric titration of the manganese(1v)solution is carried out by using oxalic acid.Iodine chloride catalyses the reduction of vanadium(v) by arsenic(II1)and enables vanadium(v) to be determined titrimetrically.The excess ofarsenic(m) used in the reduction is titrated with standard potassiumbr0mate.~~5Thiosulphate solutions acidified with boric acid can be titrated directlywith iodine using starch indicator, even after standing for 30 minutes.Boric acid can also be used for acidifying the iodine solution, but not foriodid+iodate solutions, because no iodine is liberated.226Bitskei 227 describes the use of sodium hypochlorite and thiosulphatesolutions in oxidimetric determinations in alkaline solutions. Sulphides,cyanides, thiocyanates, and hydrogen peroxide are determined by oxidationwith an excess of sodium hypochlorite; the same volume of sodium thio-sulphate solution is added and the solution is then titrated with sodiumhypochlorite, brazilin being used as indicator.In a later paper, Bitskei 228describes the determination of hydrogen peroxide by oxidation with sodiumhypochlorite; arsenious acid is used in place of sodium thiosulphate.Selenium can be determined by reduction of selenious acid to seleniumby an excess of hydrazine sulphate; the excess of hydrazine is titrated with217 A. Petzold, 2. analyt. Chem., 1956, 149, 250.21* M. N. Sastri and C. Radakrishnamurti, ibid., 1955, 147, 16.z19 I?.-E. Raurich Sas and M. Castillo Cofino, Inf. Quim. A n d . , 1956, 10, 9.z2* K. M. Somasundaram and C . V. Suryanarayana, Acfa Cham. Acad. Sci. Hung.,221 G. Gopala Rao, V. P. Rao, and N. C. Venkatamma, 2. analyt. Chew., 1956,150,z22 A. Macdonald, Ind. Chem. Mfr., 1956, 33, 280, 332.Z z 3 G.S. Deshrnukh and M. K. Joshi, Bull. Chem. SOC. Japan, 1955, 28, 449.224 I. M. Issa and I. F. Hewaidy. Ghemist-Analyst, 1955, 44, 70.?z5 G. S. Deshmukh and M. G. Bapat, 2. annlyt. Chem., 1955, 148, 347.Z z 6 E. A. Kotsis and V. Bizam, Magyar Ii%n. Folydirat, 1955, 61, 17.227 J. Bitskei, ibid., p. 406.z 2 8 Idem, Acla Chim. Acad. Sci. Hung., 1955, 8, 203.1956, 8, 423.175BELCHER, SHERIDAN, STEPHEN, AND WEST. 353potassium iodate to the iodine monochloride e n d - p ~ i n t . ~ ~ ~ Standardsolutions of hydrazine sulphate ( 0 . 1 ~ ) can be prepared from the pure solid.The solutions are stable and can be used for the reductometric titration ofa number of oxidants.230Reductor methods continue to find application in titrimetry. Molyb-denum(v1) is reduced to molybdenum(v) by the bismuth reductor; re-oxidation is effected with standard permanganate or vanadate s o l u t i o n ~ .~ ~ ~Yoshimura 2s2 uses metallic antimony and nickel as reducing agents. Anti-mony reduces iron(rI1) , tin(1v) , titanium(1v) , uranium(vI), and tungsten(v1)in acid solution, but heating is necessary. Nickel can replace lead as areductor, but the colour of the nickel ions produced in the solutions is adisadvantage. Yoshimura 233 also describes the reduction of antimony(v)to antimony(I1) using liquid zinc amalgam in SN-sodium hydroxide in thepresence of sodium pyrophosphate. Uranium(v1) , vanadium(v) , andmolybdenum(v1) can be similarly reduced. Reduction is slower in weakeralkali.The cerimetric determination of pliosphite and hypophosphite has beenstudied ; 234 Bernhardt's method 235 gives irregular results and heating to110" is necessary.However, in the presence of silver sulphate, oxidationproceeds smoothly at the temperature of a boiling-water bath. Sastri andKalidas 236 use a similar method for the determination of hypophosphite ;oxidation is effected at 100" in the presence of silver sulphate. Again,Bernhardt's findings are contradicted. Alternatives to the cerimetricmethods involve Oxidation with permanganate 237 or with d i c h r ~ m a t e . ~ ~ ~Carlyon 239 has made an exhaustive study of the oxidimeti-ic determinationof hypophosphite, phosphite, and hypophosphate.Ceric sulphate can be titrated with mercurous perchlorate by usinggold(II1) chloride as catalyst and N-phenylanthranilic acid as indicator.In 0.5-6~-sulphuric acid, the reaction is stoicheiometric.2'K) The deter-mination of hypobromite solutions can also be effected by using mercury(1)solutions.241 Permanganate is also reduced by mercury(1) in 1--3~-sulphuricThe hydrolysis of beryllium sulphate in a mixture of potassium iodideand iodate is used for the iodometric determination of beryllium.243 Theoxidimetric determination of sulphite has been studied by Indian workers.24422B B.Suseela, 2. analyt. Chem., 1955, 147, 13.230 J. Sjrka and J. Vulterin, CoZZ. Czech. Chent. Comm., 1955, 20, 804.231 E. B. Ankudimova, Trudy Komissii Anal. Khim. Akad. Nauk, S.S.S.R., 1954,232 C. Yoshimura, J . Chem. SOC. Jafan, Pure Chem. Sect., 1955, 76, 409.233 Idem, ibid., p.411.234 K. B. Rao and G. Gopala Rao, 2. nnalyt. Chem., 1955, 147, 274.235 D. N. Bernhardt, AnaZyt. Chem., 1954, 26, 1798.23G M. N. Sastri and C. Kalidas, Rec. Trav. chim., 1955, 74, 1045.2 3 7 D. Koszegi and E. Salg6, 2. analyt. Chem., 1956, 150, 262.238 G. Gopala Rao and K. B. Rao, ibid., p. 333.239 S. J. Carlyon, Diss. Abs., 1955, 15, 2401.250 V. M. Tarayan and M. G. Ekimyan, Nauch. Trudy Erevansk. Univ., 1954,4, 87.241 V. M. Tarayan and E. N. Ovsepyan, ibid., p. 77.242 V. M. Tarayan, ibid., p. 65.2p3 B. Suseela, Zhur. annlit. Khim., 1955, 10, 286.244 1< B. Rao and G. Gopala Rao, Analyl. Chim. Acta. 1955, 13, 313.REP.-VOL. LIII &I5, 197354 ANALYTICAL CHEMISTRY.No persulphate is formed if an excess of potassium permanganate is addedto the solution of the sulphite in the presence of a dilute solution of coppersulphate.Baker and McCutcheon 245 describe the redox determination ofcobalt(II1) and total cobalt in the presence of excess tungstate, using amodification of Sarver's method. When the ratio of tungsten to cobalt isless than 12.5 by weight, diphenylaminesulphonate can be used as indicator ;otherwise, suitable indication of the end-point can only be obtained potentio-metrically. Hara 246 determines periodic acid in the presence of iodic acidby titrating the mixture directly with vanadyl sulphate ; in 10N-sulphuricacid, manganous sulphate is quantitatively oxidised to permanganate byperiodic acid whilst iodic acid has no adverse effect on the reaction.Thedetermination of ammonium salts by oxidation with hypobromite (preparedin situ from 0-1N-potassium bromate and potassium bromide) has beeninvestigated; the method is accurate to *0.09%.24i '4 new iodometricmethod for the determination of gold involves treatment of the gold(rr1)chloride with sodium chlorite ; chlorine dioxide is liberated and is carriedover from the reaction vessel in a stream of carbon dioxide and absorbedin a solution of potassium iodide. The liberated iodine is determined bytitration.248Japanese workers describe the reduction of copper( 11) and iron(m)adsorbed on a column of Amberlite I.R. 180 (H) resin by a solution ofpotassium iodide.249 Reduction is quantitative and the liberated iodine inthe eluate is titrated with sodium thiosulphate.?V.I. s.Classical Organic AnalysisThe advantages of the " empty tube " technique for carbon and hydrogendeterminations have been reviewed, and improvements, based on severalyears of experience, have been suggested.250 The determination of otherelements is also discussed. The procedure has been adapted to the semi-m i ~ r o - s c a l e . ~ ~ ~ An oxygen flow of 150 ml. per minute is used, and a totaltime of 15 minutes. It is necessary to use a larger amount of manganesedioxide for the absorption of nitrogen oxides than on the micro-scale.Carbon, hydrogen, and nitrogen have been determined simultaneouslyby heating the sample covered with copper oxide in an evacuated system.252Water and carbon dioxide are condensed in traps cooled by solid carbondioxide and liquid air respectively.The pressure due to nitrogen is measuredmanometrically and the system is re-evacuated. The liquid air is replacedby water and the carbon dioxide pressure is measured. After furtherre-evacuation the solid carbon dioxide is replaced by water and the pressuredue to water vapour is measured.245 L. C. W. Baker and T. P. McCutcheon, Analyt. Chew., 1956, 27, 1625.246 S. Hara, Japan Analyst, 1956, 5, 163.947 D. Koszegi and g . Salgb, Actu Chim. Acad. Sci. Huiig., 1956, 7, 333.24* C . 33. Riolo and E. Garrini, Ann. Chim. (Italy), 1955, 45, 767.E49 H. Kakihana and K. Katou, J . Chem. Soc. Japan, Pure Chew. Sec., 1955, 76, 499.250 G. Ingram, Chem.and Ind., 1956, 103.251 G. Ingram and M. Lonsdale, ibid., p. 276.z 5 2 W. Schoniger. H P ~ . Chzm. Ado, 19.56, 39, 650BELCHER, SHERIDAN, STEPHEN, AND WEST. 355Carbon, hydrogen, and silicon can be determined simultaneously byigniting the sample in a tube containing chromium oxide-asbestos catalyst,which is placed inside the combustion The increase in weight ofthe tube containing the catalyst is due to silica; carbon and hydrogenare determined by the usual methods.In a new method carbon is determined by heating the compound withbarium nitrate, and determining the carbonate formed.25qThe properties of silver permanganate have received further study, andthe observation has been made yet again that it will absorb sulphur dioxideand nitrogen oxides at room temperature.255 It is now recommended ascatalyst in the determination of carbon and hydrogen,256 the advantagebeing claimed that a working temperature of 450" is adequate.An apparatus for the controlled combustion of spontaneously inflammablegases has been described.257 A number of improvements on the conventionalcarbon and hydrogen apparatus has been proposed by C h a r l t ~ n .~ ~ ~Kainz and ScholJer 259 recommend spongy nickel as a means of reducingnitrogen oxides. A layer 7 cm. long serves for 15-20 analyses and is thenregenerated by reduction in hydrogen.Studies have been continued with the object of improving the methodfor direct determination of oxygen. Drehkopf and Braukmann 260 recom-mend a shorter packing of activated carbon so that side-reactions areminimised.Instead of the usual iodometric finish, the carbon dioxideproduced is passed into a sodium hydroxide solution and the change inconductivity is measured. Other modifications have been proposed byHintermaier and Griiztner.261 These include the use of porcelain in placeof the quartz tube and special purification of the nitrogen. Canales andParks 262 use a palladium thimble heated to 350°, and copper gauze heatedto gooo, to remove compounds of sulphur and hydrogen formed duringpyrolysis of the sample. An amperometric titration is recommended forcompleting the determination.The Ter Meulen hydrogenation method for determination of oxygen hasbeen modified and applied to the analysis of some organic compounds andvarious carbons.263 The accuracy appears to be less than that of theSchiitze-Unterzaucher procedure.A new method for the determination of oxygen has been advanced basedon decomposition of the sample mixed with strontium oxide and graphiteZ53 V.A. Klimova, M. 0. Korshun, and E. G. Bereznitskaya, Z h w . analit. Khiitz.,254 T. S . Lee and R. Meyer, Analyt. Chim. Actn, 1955, 13, 340.255 J. Korbl, Coll. Czech. Chem. Comm., 1955, 20, 948; cf. R. Belcher, J . SOC.Chem. Ind., 1945, 64, 111 : R. Belcher and G. Ingram, Analyt. Chim. Acta, 1950, 4, 401.258 J. Korbl, Coll. Czech. Chem. Comm., 1955, 953, 1026; J. Korbl and K. Blabolil,ibid., 1956, 21, 318.257 H. B. Bradley, Analyt. Ghem., 1955, 27, 2021.26B F. E. Charlton, Analyst, 1956, 81, 582.250 G.Kainz and F. %holler, 2. ana2yt. Chem., 1955, 148, 6.180 K. Drehkopf and B. Braukmann, Bremstoff. Chem., 1955, 36, 203.A. Hintermaier and R. Griiztner, Mikrochim. A d a , 1956, 944.269 A. M. Canales and T. D. Parks, Analyt. Chim. Acta, 1956, 15, 25.283 R. N. Smith, J . Duffiield, R. A. Pierotti, and 1. Mooi, Analzit. Chem., 1956, 28,1956, 11, 223.1161356 ANALYTICAL CHEMISTRY.in a nickel bomb or sealed tube."* Carbonate is formed and is determinedtitrimetrically. The method is applicable only to compounds containingcarbon, hydrogen, and oxygen.A further new method has been described in which the sample is decom-posed in an oxygen bomb and the change in pressure is measured mano-metrically.264 Corrections are necessary when nitrogen and sulphur arepresent.The method of Marcali and R i e ~ n a n , ~ ~ ~ which avoids distillation byapplication of the well-known formaldehyde titration procedure, has beenmodified so that selenium may be used as catalyst.266 After digestion,elemental selenium is precipitated by sulphurous acid and excess of thelatter is boiled out.The titration is then done in the usual way. Inanother method which eliminaies distillation, decomposition is effected inthe presence of mercury catalyst, the solution is neutralised, and theammonium salt is titrated with standard sodium hypochlorite solution.267Chromous sdphate or chloride has been used for the reduction of nitro-groups before applying the conventional Kjeldahl procedure.268 Thereaction is instantaneous. When the reagent was applied to the reductionof azobenzene, recoveries were low.Several new procedures for the determination of sulphur have beendescribed.Iritani and Tanaka 269 heat the sample with fuming nitric acidin a sealed tube for 5 hours at 250". The excess of nitric acid is evaporatedoff and the sulphate is titrated with standard barium chloride solution.Sodium rhodizonate test-paper is used to detect the end-point. Tanaka 270uses a similar decomposition method, but treats the solution with bariumchromate. The chromate liberated, which is equivalent to the sulphatepresent, is titrated with a standard solution of Mohr's salt.In a further modification of the Carius method the sample is decomposedin the presence of barium c h l ~ r i d e .~ ~ l The barium sulphate formed iswashed and treated with an ion-exchanger pretreated with hydrochloric acid.Sulphuric acid is produced and is determined alkalimetrically.Rosenthaler272 determines sulphur in a wide variety of substances byoxidation with sodium hypochlorite at room temperature for 12 hours.Sulphate is finally precipitated as barium sulphate and weighed as such.Oxidation with nitric-perchloric acid mixtures has again been examined ;the sulphate formed is reduced to sulphide and determined iodometrically.Recoveries ranged from 98-7 to 101~4%.~'~Korbl and Piibil 274 absorb sulphur oxides in the catalytic mixture(approximating to silver oxide and manganese dioxide) formed by thermal264 J . W. Whitaker, R.N. Chakravorty, and A. K. Ghosh, J . Sci. Ind. Res., India,1956, B, 15, 72.m5 K. Marcali and W. Rieman, Iwd. Eng. Chem. Anal., 1948, 20, 381.266 C. I. Adams and G. 13. Spaulding, ibid., 1955, 27, 1003.267 R. Belclier and M. K. Bhatty, Mikrochim. Acta, 1956, 1183.268 Idem, Analyst, 1956, 81, 124.268 N. Iritani and Y . Tanaka, Kunzamoto Pharm. Bull., 1955, 30.270 Y . Tanaka, J . Pharm. Soc., Japan, 1955, 75, 653.2 7 1 J. Smith and A. C. Syme, Analyst, 1956, 81, 302.272 L. Rosenthaler, Pharm. Acta HeEv., 1956, 30, 282.273 P. 0. Bethge, Analyt. Chem., 1956, 28, 119.274 J. Korbl and R. Piibil, CoEZ. Czech. Chem. Comm., 1056, 21, 315BELCHER, SHERIDAN, STEPHEN, AND WEST. 357decomposition of silver permanganate. Silver sulphate is formed.I t isconverted into metallic silver and an equivalent amount of manganoussulphate by the addition of urea-hydrogen peroxide. Manganese is thentitrated complexometrically with EDTA in the usual way.Chlorine, bromine, and iodine have been determined by potentiometrictitration after the conventional catalytic combustion procedure.275 Clark'ssilver-amalgamated silver electrode system 276 is recommended. Ionisablehalogen is determined directly in ethanolic solution. A precision of 0.3%can be obtained with 1 - 4 mg. of asmple.Inglis 277 prefers to decompose the sample in a Parr micro-bomb. Thehalide is titrated potentiometrically, a platinum indicator electrode and amercury-mercurous sulphate reference electrode being used.A modified Stepanow procedure has been described.278 The compoundis refluxed with a 15% solution of ethylene glycol in isobutyl alcohol in thepresence of metallic sodium.Halide is then titrated mercurimetrically,diphenylcarbazone being used as indicator.Mercury in organic compounds has been determined by refluxing thesample with hydriodic acid containing iodine; HgI,2- is formed and isprecipitated and weighed as propylenediaminecupric merc~ri-iodide.~~~For the determination of acetyl or benzoyl groups, Tani and Nara280recommend saponification of 4-10 mg. of sample with 1 ml. of S~-sodiurnhydroxide solution and 2 ml. of ethanol. The solution is then passedthrough a column of Amberlite 1.R.-120 (H) resin and the eluate containingacetic or benzoic acid is titrated with 0.01N-alkali.The N-methyl determination has been improved.281 The vapours ofhydriodic acid and iodine, which are produced when N-methyl groups areconverted into quaternary ammonium salts, are trapped in a solution ofsodium thiosulphate.The error is then decreased to &0.3%. It shouldbe pointed out, however, that significant amounts of methyl iodide areabsorbed by this reagent282 and the increased accuracy may be due tocompensation of errors. Bethge and Carlson 283 have described an improvedapparatus for determination of alkoxyl groups. Various types of washsolution were compared. A spectrophotometric method for determinationof methoxyl has been proposed : 284 methoxyl is hydrolysed to give methanolwhich is then oxidised to formaldehyde; the latter is condensed withchromotropic acid and the intensity of colour is measured.Several reviews of developments in particular methods have beenR.B.276 E. C. Cogbill and J. J. Kirkland, AnaZyt. Chem., 1965, 27, 1611.2 7 6 W. Clark, J.. 1926, 749.z 7 ? J. Inglis, Mikrochim. Acta, 1955, 934.2 7 8 L. N. Lapin and R. K. Zamanov, Zhur. analit. Chem., 1955, 10, 364.2i3 H. F. Walton and H. A. Smith, AnaZyt. Chem., 1966, 28, 406.28" H. Tani and A. Nara, J . Pharm. Soc., Jafian, 1954, 74, 1399.R81 F. Sudo, D. Shimoe, and T. Tsujii, Japan Analyst, 1954, 3, 403.283 P. 0. Rethge and 0. T. Carlson, AnaZyt. Chim. Acta, 1956, 15, 279.284 M. I?. Mathers and M. J. Pro, Anal@. Chem., 1955, 27, 1662.285 J. E. Fildes, I n d . Chem., 1955, 31, 355, 412; cf.W. Schtlniger, MikrocAim. Ada,A. Slater, J., 1904, 85, 1286; cf. B. Saville, Chem. and Ind., 1956, 660.1956, 1456358 ANALYTICAL CHEMISTRY.Polarogr ap hyGeneral and Inorganic.-The conventional mercury pool and calomelelectrodes are not generally suitable as reference electrodes in continuouspolarography because they become polarised rather quickly. Two systemshave been described in which it is shown that a dropping-mercury electrodecan function satisfactorily as a reference electrode.286 These methods wereapplied to the determination of carbon monoxide in air and to that of ironand titanium during the automatic control of a process for the preparationof titanium dioxide. The use of reference electrodes with soluble reactionproducts for the continuous analysis of various processes has been examinedby the same A gas-washed mercury pool has been used asindicator electrode for the continuous determination of oxygen in industrialgases in concentrations of <0.1% and for the determination of mercury ineffluents.2a8 An improved apparatus for the observation of current-voltage,reduction, and re-oxidation patterns in oscillographic polarography hasbeen described by Imai and his co-worker~.~~~- 290 Studies were carried outon the characteristics of the peak current and the peak potential of anirreversible d e p ~ l a r i s e r , ~ ~ ~ and on the influence of initial sweep voltage andhead of mercury on the irreversibility of the depolari~er.2~2 An oscillo-graphic polarograph with saw-tooth wave and electrochemical depolarisationof solid amalgamated electrodes by Skobets's short-circuiting method hasbeen de~cribed.2~~ Further application of the sensitive square-wave polaro-graph has been described by Ferrett and Milner.294 Methods for measuringthe wave height of polarograms have been discussed.295 Studies have beenmade of the effects of cell circuit resistance with stationary and droppingelectrodes 296 and of an instrument in which automatic cell voltage controlis used for the accurate determination of half-wave potentials.297 Micro-molar solutions have been investigated by using a mercury-pool cathode instirred s0lutions.~~8 An electrode surface of 3 sq.cm. gave a sensitivity300 times greater than that obtained with a dropping cathode using the samecircuit.Considerable attention continues to be paid to the properties of varioussupporting electrolytes and the merits of various solvents.Thus, reportshave appeared on tetramethylammonium chloride,2N trimetliylphenyl-ammonium hydroxide,3O" hydrazine, pyridine, thiocyanate, pyrophosphate,2a8 J. V. A. NovBk, Coll. Czech. Chem. Comm., 1955, 20, 1076.287 Idem, ibid., p. 1090.288 Idem, Chem. Listy, 1955, 49, 1476.290 M. Shinagawa and H. Imai, ibid., p. 187.291 H. Imai, ibid., p. 530.292 Idem, ibid., p. 583.293 I. I. Tsapiv, Zhur. analit. Khim., 1966, 11, 63.294 D. J . Ferrett and G. W. C. Milner, Analyst, 1966, 81, 193.295 R. S. Subrahmanya, J. Indian Inst. Sci., A , 1956, 38, 26.296 M. M. Nicholson, Analyt. Chem., 1965, 27, 1364.297 R.L. Pecsok and R. W. Farmer, ibid., 1956, 28, 986.298 D. J. Rosie and W. D. Cooke, ibid., 1965, 2'4, 1360.499 P. L. Pickard and W. E. Neptune, ibid., p. 1358.300 M. Friedrich, Chem. Lzsty, 1955, 49, 1241.M. Shinagawa, H. Imai, and S. Chaki, J. EZectrochem. SOC. (Japan), 1955, 23, 132BELCHER, SHERIDAN, STEPHEN, AND WEST. 359et~.,~Ol and on the polarography of various ions in ethanol 302 and ethylene-diamine.303 Japanese workers have investigated the polarography ofvarious cations in the presence of tetramethylammonium iodide,3a tri-phenylselenonium chloride,3o5 triphenyltelluronium chloride,mg dodecyl-trimethylammonium chloride,307 triphenylsulphonium chloride,3O8 andtriphenylphosphonium c h l ~ r i d e .~ ~ Tetrabutylammonium iodide has beenused as supporting electrolyte to permit the polarography of potassiunitetraphenylboron in di~nethylformamide.~~~ The reduction of nitrate atthe dropping electrode in the presence of the glycine complex of chromium(rI1)gives a new wave.311 Iodide, bromide, and sulphide have been determinedpolarographically in petr~leum-water.~~~Oscillographic polarography has been used for the detection of iron andcopper and for the determination of nickel in cobalt salts.313 Iron andcopper have also been determined in high-purity aluminium 314 and in zincand zinc alloys, along with cadmium and lead.315 Iron has similarly beendetermined with several other trace metals in refined copper.316 2 : 2’ : 2”-Trihydroxytriethylamine (triethanolamine) has been used to obtain well-defined waves for the determination of iron and manganese in cement andslags.EDTA was used to suppress the interference of large amounts ofcalcium and magnesium.317 The separate polarographic determination ofmanganese oxides of different valency has been described by a Russianauthor.318 Nickel has been polarographed with calcium chloride as support-ing electrolyte in the presence of pyridine or t h i ~ c y a n a t e . ~ ~ ~ The samesupporting electrolyte has been used for the determination of chromium inthe presence of nickel after suppressing the wave due t o the latter by additionof hydr~xylamine.~~~ Nickel has also been determined polarographically inantimony and tin alloys along with copper, cadmium, lead, and ~inc.~21The last element has been determined polarographically in magnesiumalloys,322 in copper ~ u l p h a t e , ~ ~ ~ and in the presence of aluminium.324 Cad-301 J.W. Grenier and L. Meites, Analyt. Chim. A d a , 1956, 14, 482.302 Ya. I. Turiyan, Zhuu. analit. Khim., 1956, 11, 71.303 J. Dolezal, Chem. Listy, 1955, 49, 1237.304 M. Shinagawa and H. Matsuo, Japan Analyst, 1964, 3, 114.~5 M. Shinagawa, H. Matsuo, and S. Isshiki, ibid., p. 199.306 M. Shinagawa, H. Matsuo, and H. Sunahara, ibid., p. 204.3u7 M. Shinagawa and H. Matsuo, ibid., 1955, 4, 213.308 M. Shinagawa, H. Matsuo, and N. Maki, ibid., 1956, 5, 80.31x2 M. Shinagawa, H. Matsuo, and H. Nezu, ibid., p. 20.310 A. F. Findeis and T. De Vries, Analyt. Chem., 1956, 28, 209.311 R.E. Hamm and C. D. Withrow, ibid., 1955, 27, 1913.312 N. Hemala, J. Marek, and 2. Valcikova, Ref. Zhur., Khim., 1956, Abstr. No. 4098.313 J. Dolezal and P. Hofmann, Chew. Listy. 1954, 48, 1610.y15 J. Dolezal and P. Hofmann, Chem. Listy, 1965, 49, 47.316 A. J. Eve and E. T. Verdier, AnaZyt. Chem., 1956, 28, 537.317 M. Pleva, Chem. Listy, 1965, 49, 262.318 V. S. Fikhtengol’ts, Zavodskaya Lab., 1955, 21, 1036.318 K. P. Privilova, Kh. 2. Avrutova, and N. Ya. Khlopin, ibid., p. 670.320 J. S. Beveridge, G. F. Reynolds, and H. I . Shalgosky, AnaZyt. Chim. Acta, 1955,321 T. V. Aref’eva and R. G. Pats, Ref. Zhur., Khim., 1956, Abstr. No. 7143.322 I. V. Izvekov and N. T. Movchan, ibid., 1955, Abstr. No. 14,207.325 J. W. Menary, Analyst, 1955, 80, 908.324 I.Rozsai, Magyar Kkm. Fol?ldirat, 1956, 62, 139.R. Neumann, 2. anorg. Chem., 1955, 279, 234.13, 494360 ANALYTICAL CHEMISTRY.mium has been determined similarly in zinc salts 325 and copper-containingzinc materials.326 A streaming-mercury cathode and 0.7~-tetramethyl-ammonium chloride base electrolyte gave good results for the polarographyof magnesium between pH 5.4 and 6.8.327 Potassium did not interfere withthis method but calcium and lithium did. Lead and thallium have beendetermined in metallic cadmium 328 by extracting the bromide of thalliumwith ether and polarographing it in aqueous ammonium sulphate solution.The unextracted lead was polarographed in 3~-hydrochloric acid in thepresence of the cadmium.The polarography of molybdenum after ion-exchange separation from interfering ions has been described. The deter-mination may be carried out in the presence of tungsten.329 Kolthoff andWatters's method for cobalt has been modified by Meites; 330 the method isapplicable in the presence of nickel. Antimony has been determined inglass by polarographing a solution of the sample in hydrofluoric acid andoxalic acid.331 The interference of arsenic in the polarographic determin-ation of antimony, and its elimination, have been Methods havebeen reported for the direct 333 and indirect 334 determination of selenium.Uranium has been determined in shale, etc., after extraction of uranylnitrate from the sample dissolved in perchloric acid-nitric a~id.33~ Platinumhas been determined by polarography in O-lN-nitrite solution by usingsolid platinum electrodes.336 The polarography of praseodymium withlithium chloride and tetramethylammonium iodide base-electrolytes hasbeen reported by Japanese workers." Square-wave polarography hasbeen used to study the behaviour of niobium in various complexing media,338and more conventional oscillographic technique to differentiate betweenniobium and titanium in 23~-sulphuric acid.339 Polarographic determin-ation of these two metals in ~ 6 0 % sulphuric acid has been studied byothers.=O Various authors have reported on the polarographic determin-ation of tin in ores,341, a2 in iron and steel,= and in metallic zinc 344 andzinc electrolytes.In the last case, lead and cadmium were simultaneouslydetermined, without using any separation techniques.326 N.I. Solontsev, E. M. Tal, 2. P. Lopatina, and E. I. Dubovitskaya, Ref. ZhZlY.,328 J. Dolezal and P. Hofmann, Chem. Listy, 1955, 49, 1026.327 K. Gyorbiro, L. Poos, and J. Proszt, Magyav I<Lm. Folydivat, 1956, 61, 102.328 T. V. Aref'eva, R. G. Pats, and A. A. Pozdnyakova, Ref. Zhur., Khim., 1956,329 R. L. Pecsok and R. M. Packhurst, AnaJyt. Cham., 1955, 27, 1920.330 L. Meites, ibid., 1956, 28, 404.881 J. P. Williams and T. A. Schwenkler, J . Amer. Ceram. SOC., 1955, 38, 367.332 G. Packman and G. F. Reynolds, Analyst, 1956, 81, 49.333 A. Cervenka and M. Korbovb, Chem. Listy, 1955, 49, 1158.334 H. Hahn and W. Kleinwort, 2. nnalyt. Chem., 1956, 151, 98.335 I<.Kaarik, Suomen Kern., 1966, B, 29, 1.336 hl. B. Bardin and Yu. S. Lyalikov, Zhur. aszalit. Khim., 1955, 10, 305.337 S. Misumi and A. Iwase, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1231.338 D. J. Ferrett and G. W. C. Milner, J., 1956, 1186.839 Ya. P. Gokhshtein, Zavodskuya Lab., 1966, 22, 38.340 E. I. Krylov and V. S. Kolevatova, ibid., 1955, 21, 91 1.341 D. L. Love and S. C. Sun, Analyt. Chem., 1955, 27, 1557.342 I. A. Blyum and N. G. Zyryanova, Zavodskaya Lab., 1956, 22, 46.343 H. Goto, S. Ikeda, and S. Watanahe, Jnpan Analyst, 1954, 3, 320.344 F. K. Baev and P. N. Kovalenko, Zavodskaya Lab., 1955, 21, 1170.Khim., 1956, Abstr. No. 7092.Abstr. No. 9099BELCHER, SHERIDAN, STEPHEN, AND WEST. 361Organic.-Considerations of space restrict the review of organic polaro-graphy in this Report to only a very brief survey of the many papers pub-lished during the period covered.Considerable work continues to be doneon the “ functional-group ” aspect of organic polarography. Thus, methodshave been published for the determination of saturated fattyaldehydes,346 carbonyl compo~nds,34~ azo-compounds,34* unsaturated com-p o u n d ~ , ~ ~ purine compounds,35o keto-~teroids,~~~~ 352 monohalogeno-acetones,3= etc. The anodic polarography of phenylenediamines hasbeen studied at a rotating platinum electrode. A semi-quantitative analysiswas obtained for mixtures of the 0- and @-diamine~.~a Methods for vitaminA,356 and thiamine in the presence of vitamin A,356 have been described.Morphine 357 and atropine 358 have also been determined polarographically.Ethyl nitrate and ethyl nitrite have been determined in aqueous solution.The solubility of ethyl nitrate was thus found to be ca.1.3% at Inthe field of polymer chemistry, polarography has been used to determinebenzoyl peroxide in poly(methy1 methac~ylate),~~ and phthalic anhydride inalkyd resins.361 Sulphur in organic compounds has been determined bytreatment with Raney nickel to form sulphide, which is then polarographedin sodium hydroxide. The presence of nitrogen does not interfere with thismeth0d.~*2 Polarography has been used to control the salting out ofproteins. The process depends on the presence of the tervalent cobaltAmperometric Titration.-The amperometric titration of various cationsin micromolar solutions ( 10-5-10-7~) using a mercury-pool indicatorelectrode in conjunction with EDTA as titrant has been des~ribed.~MThe electrode area was 1-2 sq.cm. and stirring was effected by nitrogen.The use of various organic reagents such as (‘ amidopyrine,” diantipyrinyl-methane, and diantipyrinylphenylmethane has been and alsothe use of more conventional reagents such as a-benzoin oxime, l-nitroso-%naphthol, 8-hydroxyquinolineJ and pyrogallol.366 Two- and three-ion .363345 s. Maruta and F. Iwama, J . Chem. SOL. Japan, Pure Chem. Sect., 1955, 76, 548.346 L. N. Petrova and E. N. Novikova, Zhur. priklad. Khim., 1955, 28, 219.347 W. Rogers and S. M . Kipnes, Amlyt. Chem., 1955, 27, 1916.34* G. DuSinsk? and 2.Gruntova, Cesk. Farm., 1955, 4, 445.349 A. V. Ryabov and G. D. Panova, Doklady Akad. Nauk, S.S.S.R., 1954, 99,350 N. G. Luthy and B. Lamb, J . Pharm. Pharmacol., 1956, 8, 410.351 C. J. 0. R. Moms, Rec. Trav. chim., 1955, 74, 476.352 D. M. Robertson, Riochcm. J., 1955, 81, 681.353 P. J. Elvingand R. E. Van Atta, Analyt. Chern., 1955, 27, 1908.354 R. E. Parker and R. N. Adams, ibid., 1956, 28, 828.355 W. Keller and F. Weiss, 2. analyt. Chem., 1955, 148, 26.356 A. M. Shkodin and G. P. Tikhomirova, UKraiTz. Rhim. Zhur., 1955, 21, 265.35i J. Holubek, Pharnz. Zentrallz., 1955, 94, 347.358 B. Novotng, Cesk. Favm., 1955, 4, 448.359 -4. Blyumberg and V. L. Pikaeva, Zhur. analit. Khim., 1955, 10, 310.3c0 T. Takeuchi, N. Yokouchi, and Y. Takayama, Japan Analyst, 1955, 4, 234.3 6 1 P.D. Garn and E. Mi. Halline, Analyt. Chem., 1966, 27, 1563.362 As. Trifonova, Ch. Ivanov, and D. Pavlov, Compt. rend., Acad. Bztl~. Sci., 1954,363 V. Kalous and J. Stokr, Chewz. Listy, 1955, 49, 565.364 3 . G. Nikelly and ‘IV. D. Cooke, AnaZyt. Chenz., 1956, 28, 243.365 A. A. Popel’, Uch. Zap. Kazansk. Uniu., 1955, 115, 69.3ti6 T. K. Musina and 0. A. Songina, Ref. Zhur., Khim., 1956, Abstr. No. 4090.547.7, 1362 ANALYTICAL CHEMISTRY.component mixtures, e.g., Bi-Ca-Pb, have been titrated with EDTA.367EDTA itself has been titrated amperometrically with zinc ions. By thismethod both total and available EDTA can be determined.368 Anthranilicacid has been used as titrant for various cations, e.g., cobalt,37OTitanium was titrated amperometrically with cup-ferron 3739 374 and bismuth by triphenylselenonium chloride 375 and potassiumiodide.376 Zirconium has also been titrated with cupferron 377 in thepresence of magnesium.Manganese and molybdenum in ferromanganeseand ferromolybdenum 378 have been determined amperometrically bytitration with ferrocyanide, and tungsten in ferrotungsten 379 by titrationwith 8-hydroxyquinoline. Amperometric methods for vanadium havebeen described in which vanadium(1v) and iron(I1) have been titrateddifferentially with ceric sulphate 380 and vanadium(v) has been titratedwith i r o n ( ~ ~ ) , ~ * l and in which an oxide electrode of high positive potentialhas been used for the titration of vanadate and chromate with iron(^^).^*^Triphosphate ion has been used for the titration of lead,383 cadmium,384 andnicke1.385 Silver ions have been titrated amperometrically with iodideion 386 and with the organic reagents mercaptophenylthiothiadiazolone andmercaptobenzothiazole.387 Thallium has been determined by the anodicbromide method 388 and copper with rubeanic acid.389 Antimony has beendetermined in alloys by dichromate t i t r a t i ~ n , ~ ~ ~ and magnesium (and possiblyberyllium) by titration with m- and ~-phenylazoresor~inol.~~~Thus,a systematic study of the behaviour of silver halides at a rotating platinumelectrode has been made.The presence of gelatin was shown to be essen-tia1.392 Fluoride ion has been titrated with ferric chloride by varyingandSeveral methods have been proposed for the titration of anions.3'i7 C.N. Reilley, W. G. Scribner, and C. Temple, Analyt. Chem., 1956, 28, 450.368 W. S. Wise and N. 0. Schmidt, ibid., 1955, 27, 1469.368 A. K. Zhdanov and R. T. Tseitlin, Ref. Zhur., Khim., 1955, Abstr. No.370 A. K. Zhdanov and A. M. Yakubov, ibid., Abstr. No. 29,114.371 Idem, ibid., Abstr. No. 29,113.372 Idem, ibid., Abstr. No. 29,112.373 Yu. I . Usatenko and G. E. Bekleshova, Zavodskaya Lab., 1955, 21, 779.374 V. M. Peshkova and 2. A. Gallai, Ref. Zhur., Khim., 1955, Abstr. No. 37,610.376 M. Shinagawa and H. Matsuo, Japan Analyst, 1955, 4, 211.377 P. J. Elving and E. C. Olson, Analyt. Chem., 1956, 28, 261.378 N. M. Degterev, Zavodskaya Lab., 1955, 21, 917.3 7 9 Idem, ibid., 1956, 22, 167.380 I.P. Alimarin and S . I. Terin, ibid., 1955, 21, 777.381 C. L. Rulfs, J. J . Lagowski, and R. E. Rahor, Analyt. Chem., 1956, 28, 84.382 M. Ishibashi, T. Fujinaga, and H. Sinozaka, J. Chem. SOC. Japan, Pure Chem.388 M. Kobayashi, ibid., 1955, 76, 799.384 Idem, ibid., p. 1023.386 Idem, ibid., p. 796.38* 0. A. Songina and A. R. Voiloshnikova, Zavodskaya Lab., 1956, 22, 19.389 A. K. Zhdanov, V. A. Khadeev, and 0. K. Vyakozina, ibid., 1955, 21, 913.yyu I. Bozsai, Magyar Kim. Folydirat, 1955, 61, 305.391 A. I. Kostiomin, Ref. Z h w . , Khim., 1956, Abstr. NO. 1105.392 I . M. Kolthoff and J . T. Stock, A ~ a l y s t , 1955, 80, 860.29,111.A. K. Zhdanov, V. A. Khadeev, and G. F. Murtazinova, Zavodskizya Lab., 1955,21, 518.Sect., 1956, 77, 265.0.A. Songina, Zavodskuya Lab., 1955, 21, 665.M. Malinek and B. RehBk, 2. analyt. Chem., 1956, 150, 329BELCHER, SHERIDAN, STEPHEN, AND WEST. 363techniques.3g3> 394 Ferrocyanide and phosphate have been titrated ampero-metrically with vanadyl ~alts.3~5 Various organic bases, particularlyalkaloids, have been titrated amperometrically with tungstosilicic acid 396and with tungstophosphoric and molybdophosphoric acid.397 Pyridine hasbeen tit rated with copper t h iocyanat e,398 and various photographic develop-ing agents with d i c h r ~ m a t e . ~ ~ ~Absorptiometric MethodsIn this field of analysis, few developments of outstanding importanceare to be reported. As usual, most papers on absorptiometric methods dealwith applications or modifications of existing methods.Copper has beendetermined by various methods: by addition of hydrochloric acid andmeasurement in the near infrared region,400 by use of nitric acid in a similarmanner for the analysis of slags and converter matte,401 by measuring theabsorption of the cuprarnmonium ion for the analysis of non-ferrous alloys,4o2by use of neocuproin in the analysis of tungsten 403 and aluminium andlead-tin solder,404 with diquinolyl in iron and with 2-hydroxy-ethylamine in lead-antimony alloys,406 with a-benzoin oxirne in molybdenumproducts.407 Two new methods for copper use catechol-violet 408 and oxalyl-dihydrazide36 as reagents. Many papers are concerned with the deter-mination of iron. Amongst the reagents described are the following : 1 : 10-phenanthroline for iron in lead-tin alloys 409 and in high-purity aluminium 410and other non-ferrous metals ; 4 : 7-diphenyl-1 : 10-phenanthroline in high-purity tungsten ; 411 4 : 7-dihydroxy-1 : 10-phenanthroline in stronglyalkaline solution; 39 tartaric acid in the ultraviolet region for the analysisof rocks 412 and copper alloys; 413 pyrogallol in the presence of several othercations.414 Three new methods have been described for the determinationof iron.The reagents used are m-methoxy-o-nitrosophenol,415 ethylene-393 S. Musha and T. Higashino, J . Chem. SOC. Japan, Pure Chem. Sect., 1956, 77, 128.394 K. KadiE and 2. hez&E, Chem. Listy, 1955, 49, 570.39L V. L. Zolotavin and V. K. Kuznetsova, Zavodskaya Lab., 1955, 21, 1283.396 M.SouEkovA and J. Zjrka, Cesk. Farm., 1955, 4, 181.397 Idem, ibid., p. 227.398 M. Munemori, J . Chem. SOC. .Japaw, Pure Chent. Sect., 1955, 76, 1173.30B J. Zjrka, Chem. Listy, 1954, 48, 1864.dm D. G. Davis and H. M. Hershenson, Anal$. Chim. Acfa, 1965, 13, 150.401 S. Ikeda, Japan Analyst, 1955, 4, 286.do2 H. Pohl, Metall. 1955, 9, 102.u3 R. H. A. Crawley, Analyt. Chim. Acfa, 1955, 13, 373.404 J . W. Fulton and J . Hastings, Analyt. Chena. ,1956, 28, 174.‘ 0 5 B.I.S.R.A., Methods of Analysis Committee, J . Iroiz Sfeel Inst., 1956, 182, 301.wU I. P. Ryazanov and N. I. Davydova, Ref. Zhu.r., Khivz., 1955, Abstr. KO. 14,198.4 0 7 J . Madera, Analyt. Chem., 1955, 27, 2003.408 V. Svach, 2. aszalyt. Chem., 1956, 149, 417.4u9 I<.Ota, Japan Analyst., 1956, 5 , 3.41n H. Pohl, Aluminium, 1955, 31, 207.R. H. A. Crawley and M. L. Aspinal, Analyf. Chim. Acta, 1955, 13, 376.412 S. Yokosuka, M. Tanaka, and H. hlorikawa, Japan Analyst, 1955, 4, 434.J’s W. Nielsch and G . Boltz, Metall, 1954, 8, 866.414 M. Yana, H. Mochizuki, R. Kajiyama, and T. Misaki, Ja$an Analyst, 1955, 4,‘15 T. Torii, J . Chew. SOC. Japan, Pure Chem. Sect., 1955, 76, 333.606364 ANALYTICAL CHEMISTRY.diaminebis-sulphosalicylaldehyde,416 and 5-sulphoanthranilic a ~ i d . ~ 8 Cobalthas been determined absorptiometrically by means of l-nitroso-2-naphth01,417. m-methoxy-o-nitrosopheno1,418 p-mercaptopropionic potassium ethyl~ a n t h a t e , ~ l ~ thiocyanate, and tributylammonium acetate,420 and as the tetra-phenylphosphonium thiocyanatocobaltic Methods for chromiumuse the following reagents : diphenylcarba~ide,~~~~ 423 o-aminophenyldithio-carbamic acid,47 ethylenediaminetetra-acetic and the intense bluecolour of the perchromic acid complex.425 In the determination of man-ganese, variants of the permanganate (bismuthate) method have been427 and a method based on the catalytic activity of manganousions in the reduction of chromate 428 has been proposed. Dimethylglyoximehas been used for the determination of nickel in tungsten p0wder,42~ and itssodium salt similarly.430 In both cases, the nickel complex was extractedinto a non-miscible solvent.Tin has been determined by means of itsreactions with morin 431 and tol~enedithiol.~~~ Silver has been determinedin photographic emulsions by measuring the absorption of colloidallysuspended silver s ~ l p h i d e .~ ~ An ultramicro-method for halides uses theliberation of diphenylthiocarbazone from its silver complex in an ethylacetate-chloroform solvent as a means of determination.& Thorium hasbeen determined by use of n e ~ t h o r i n , ~ ~ m r e l l i n , ~ ~ ~ catechol-violet ,437n a p h t h a ~ a r i n , ~ ~ ~ phosphom~Iybdate,~~~ and arsenophenylazonaphthol-sulphonic acid.@ Thallium has been determined indirectly after precipit-ation of [Co(NH3),]T1C1, by application of a cobalt-thiocyanate procedure.440Direct determination has been effected by utilising the formation of anextractable thallium-methyl-violet complex.441 Cerium has been deter-mined indirectly by a method using lead dioxide, ferrous sulphate, and1 : 10-phenanthroline.442 Alizarin-S has been used extensively as a4 1 G A.K. Mukherjee, Analyt. Chim. Acta, 1955, 13, 268.417 N. Oi, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 413.418 T. Torii, ibid., p. 680.419 A. T. Bilinenko and N. V. Ul'ko, Zhur. analit. Khim., 1955, 10, 299.420 M. Ziegler, 0. Glemser, and E. Preisler, Angew. Chem., 1956, 88, 436.421 M. Shinagawa, H. Matsuo, and R. Kohara, Japan Analysf, 1956, 6, 29.422 P. F. Urone, Analyt. Chem., 1955, 27, 1354.423 K. Kitagawa and Y . Aimoto, Japan Analyst, 1955, 4, 144.424 V. G. Goryushina and E. Ya. Gailis, Zavodska-ya Lab., 1955, 21, 642.4 2 5 A. Glasner and M. Steinberg, Analyt.Chem., 1955, 27, 2008.426 T. Ito, K. Hara, and Y . Hoshino, Jafian AnaZyst, 1955, 4, 353.4 2 7 H. Kiyota and T. Yamamoto, J . Chem. SOC. Japan, Pure Chem. Sect., 1956, 76,428 G. Almdssy and I. Dezso, Ada Chim. Acad. Sci. Hung., 1965, 8, 11.429 K. L. Rohrer, Analyt. Chem., 1955, 27, 1200.430 W. Nielsch and L. Giefer, Mikrochim. Acta, 1956, 522.481 V. Patrovsky, Chem. Listy, 1954, 48, 1694.432 H. Onishi and E. B. Sandell, Analyt. Chim. Acta, 1956, 14, 163.433 A. Hulanicki and B. Gluck, Przemysl Chem., 1955, 11, 149.434 W. J. Kirsten, Mikrochim. Acta, 1955, 1086.433 M. Ishibashi and S. Higashi, Japan AnaZyst, 1956, 6, 135.436 B. R. I,. Rao and C. C. Patel, Proc. Indian Acad. Sci., 1955, A , 42, 317.437 M. Svach, 2. analyt. Chem., 1956, 149, 414.438 T.Moeller and M. Tecotzky, Analyt. Chem., 1955, 27, 1056.439 T. Nozaki, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 996.440 Idem, ibid., 1956, '77, 493.441 S. D. Gurev, Ref. Zhur., Khim., 1956, Abstr. No. 4155.442 L. Gordon and A. M. Feibush, AnaZyt. Chem., 1965, 27, 1050.11 79BELCHER, SHERJDAN, STEPHEN, AND WEST. 365colorimetric reagent for zirconium.m* 4.a 445 Flavano1,446 ar~enazo-reagent,~~and mandelic acid 448 in the ultraviolet region have also been used as reagentsfor this metal. Aluminium has been determined by means of several reagents,e.g., al~inon,449 arsenazo-reagent ,450,451 Erio~hrome-cyanine,"~~ chrome-azurol-S.453 Various methods have been used for the determination of theplatinum metals. Indium has been determined with NN-dimethyl-$-nitrosoaniline 454 and EDTA,455 ruthenium has been determined absorptio-metrically as per-r~thenate?~~ platinum as the stannous-platinous chlorideand rhodium similarly.458 l-Naphthylamine-3 : 5 : 7-trisul-phonic acid has been used for the colorimetric determination of osmium.43Bismuth has been determined by variations of the thiourea459461 and theiodide method461*462 and also by means of catech~l-violet.~~ Zinc hasbeen determined by thiocyanate and rhodamine-C 464 and by methyl-violetand ferrocyanide.465 Cadmium has been determined indirectly by 4-hydroxy-3-nitrophenylarsonic acid 466 in copper and cadmium alloys.Titan-yellow 467 and 3-[3-(2 : 4-dimethy~carboxanilido)-2-hydroxy-l-naphthylazo]-4-hydroxybenzenesulphonate 468 have been used in the absorptiometricdetermination of magnesium.Quercetin 469 and phenylfluorone 470 havebeen used as reagents for germanium. Lead has been determined by meansof q~1inalizarin,4~~ antimony by means of methyl-~iolet,~~~ and lithium 473indirectly, after precipitation as phosphate, by a phosphomolybdate method.Beryllium has been determined indirectly in a similar manner after precipit-ation as beryllium ammonium phosphate.474 It has also been determined44a D. L. Manning and J. C. White, Analyt. Chem., 1955, 21, 1389.441 K. Narita, J - Chem. SOC. Japan, Pure Chem. Ssct., 1955, 76, 1026.445 L. Silverman and D. W. Hawley, Analyt. Chem., 1956, 28, 806.446 L. Horhammer, R. Hansel, and W. Hieber, 2. analyt. Chem., 1955, 148, 251.447 V.I. Kuznetsov, L. M. Budanova, and T. V. Matrovsova, Zavodskaya Lab., 1956,4 4 ~ R. B. Hahn and L. Weber, Analyt. Chem., 1956, 28, 414.449 I. V. Bogdanova, Zavodskaya Lab., 1955, 21, 1043.459 V. I. Kmatsov and R, B. Mnbtsova, ibid., p. 1422.451 Idem, ibid., 1956, 22, 161.45a B. J. MacNultp,G. J-Hunter, and D.G. Barrett, Analyt. Chim. Ada, 1956,14, 1368.453 B. J. MacNulty and L. D. Woolard, ibid., p. 452.4 s 4 A. D. WestIand and F. E. Beamish, Amlyt. Chem., 1955, 27, 1776.4 6 5 W. M. MacNevin and 0. H. Kreige, ibid., 1956, 28, 16.4 5 6 G. A. Stoner, ibid., 1956, 27, 1186.4 5 7 0. I. Milner and G. E. Shipman, ibid., p. 1476.458 G. H. Ayres, B. L. Tuffly, and J. S. Forrester, ibid., p. 1742.450 L. N. Krasil'nikova, Ref. Zhur., Khim., 1956, Abstr.No. 4165.460 M. P. Makukha, ibid., 1955, Abstr. No. 31,889.461 N. M. Lisicki and D. F. Boltz, Awatyt. Chem., 1955, 27, 1732.4 6 3 P. Alberto-Barreto and B. Ortegui, Afinidad, 1955, 32, 149.463 M. Svach. 2. analyt. Chem., 1956, 149, 325.464 L. B. Zaichikova and N. N. Lutchenko, ZavodsRaya Lab., 1965, 21, 1304.4 6 5 V. I. Kuznetsov and L. S. Kozpeva, Ref. Zhur., Khim., 1955, Abstr. No. 26,438.4 6 6 W. Nielsch and G. Boltz, Gem.-Ztg., 1955, 79, 364.4 6 7 A. Bussman, Z . analyt. Chem., 1956, 148, 413.4 6 8 C. K. Mann and J. H. Yoe, Analyt. Chem., 1956, 28, 202.469 Y. Oka and S. Matsuo, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 610.470 L. B. Ginsburg, S. D. Gurev, and A. P. Shibarenkova, Ref. Zhur., Khim., 1966,4 7 1 V.A. Morozov, ibid., 1955. Abstr. No. 14,220.472 E. I. Ishutchenko and V. M. Eliseeva, Zavodskaya Lab., 1955, 21, 791.473 T. Nozaki, J . Chem. SOC. Japan, Pure Chena. Sect., 1955, 76, 445.4 7 4 M. Sunderasan and M. Sankar-Das, Analyst, 1955, 80, 697.22, 406.Abstr. No. 4160366 ANALYTICAL CHEMISTHY.by means of ~-nitrophenylazo-~rcinol.~~~~ 476 Variations of the arseno-molybdate procedure have been used by several authors for a r ~ e n i c . 4 ~ 7 ~ 7 ~Alizarin-red-S has been employed as colorimetric reagent for the determin-ation of scandium ; 480 samarium has been determined directly at 4016 inchloride solution.481 Ascorbic acid has been used as reagent for goidJ482dipicrylamine for potassium,483 ferrocyanide for diethylditliio-carbarnate for catechol for tantalum,486 and hydrazine forrhenium(v1) in hydrochloric acid.487 Molybdenum has been determined inthe presence of tungsten in a citrate medium by measurement of the redcolour formed with phenylhydra~ine.~~~ Sodium has been determined in-directly after precipitation as sodium zinc uranyl acetate hexahydrate bythe thiocyanate-uranyl ion The thiocyanate reaction has beenapplied to the direct determination of uranium in minerals.4go The conven-tional methods using morin 491 and ferrocyanide 492 have also been utilised,and an ultraviolet method for the uranyl ion in perchloric acid.493 Titaniumhas been determined by use of sulphosalicylic acid,494 " Tiron," 495 dianti-pyrinyl-o-hydro~yphenylmethane,49~ and c ~ p f e r r o i i .~ ~ ~ Niobium has beendetermined in the presence of titanium by a thiocyanate method.498 Nio-bium and tantalum in steel have been determined separately by means oftheir yellow-brown pyrogallol compounds in the presence of sulphite andoxalate respecti~ely.4~9*5'-'O Hydrogen peroxide has also been used in aphotometric method for niobium(v) and tantalum(v) .501 Several methodshave been proposed for the determination of vanadium.These methods4 7 5 J. B. Pollock, Analyst, 1956, 81, 45.476 J. C. White, A. S. Meyer, and D. L. Manning, Analyt. Chem., 1956, 28,4 7 7 M. Jean, Analyt. Chim. Acta, 1956, 14, 172.478 F. L. Hahn and R. Luckhaus, 2. analyt. Chem., 1956, 149, 172.479 H. W. Berkhout, Chemist-AnaZyst, 1956, 45, 24.48O A. R. Eberle and M.W. Lerner, Analyt. Chem., 1955, 27, 1551.4 8 1 R. Rasin-Streden, W. Dauschan, and 0. Zemek, Mikrochim. Acta, 1956,482 S. Ya. Shnaiderman, Ukrain. Khirn. Zhur., 1955, 21, 261.4S3 P. R. Lewis, Analyst, 1955, 80, 768.484 G. d'Amore, Ann. Chim (Italy), 1955, 45, 759.485 H. Got6 and Y . Kakita, Japan Analyst, 1954, 3, 299.486 B. Sarma and J. Gupta, J . Indian Chem. SOC., 1956, 32, 285.487 R. J. Meyer and C. L. Rulfs, Analyt. Chem., 1955, 27, 1387.488 E. M. Goldstein, Chemist-Analyst, 1956, 45, 47.48O P. N. Kovalenko and V. V. Ten'kovtsev, Ref. Zhuv., Khim., 1955, Abstr. KO.490 M. M. Tillu, D. V. Bhatnagar, and T. K. S. Murthy, Proc. Indian Acnd. Sci.,491 M. T. Beck and E. Hanlos, Acta Chim. Acad. Sci. Hung., 1955, 8, 233.492 C. Ujhelyi, Magyar Kkm.Folydirat, 1955, 61, 437.493 L. Silverman and L. Mondy, Analyt. Chem., 1956, 28, 45.494 17. Steuer and H. Dunkel, Aluminium, 1955, 31, 205.405 R. Szarvas and B. Csiszar, Acta Chim. Acad. Sci. Hung., 1955, 7 , 403.4 s i 17. Buscarons and J. L. Marin-Malumbres, Anales real. SOC. Espafi. Fis. Quitn.,498 li. J. Mundy, Analyt. Chem., 1955, 27, 1408.499 A. Eder, Arch. Eisenhiittenw., 1955, 26, 431.5.00 M. Yana, H. Mochizuki, R. Kajiyama, and T. Misaki, Jafian Analyst, 1955, 4,5Ql H . SchBfer and F. Schnlte, Z . nnnlyf. Chem., 1966, 149, $3.956.512.16,552.1955, A , 42, 28.S. I. Gusev and R. G. Beiles, Ref. Zhur., Khim., 1955, Abstr. No. 26,450.1965, B, 51, 121.40!1BELCHER, SHERIDAN, STEPHEN, AND WEST. 367indicate the use of benzohydroxamic acid,502 ferrous dipyridyl,503 diphenyl-aminesulphonic acid,* catech01,~O~ oxidation of aniline,506 and a high-precision variation of the standard peroxy-vanadium procedure.507Numerous methods have been proposed for anionic inorganic substances.Only a few of these can be mentioned here. Fluoride has been determined byits action on the coloured product fokmed by ascorbic acid with titanium,508also on that formed between neothorin and thorium 509 and on the thorium-alizarin c0mplex,5~~ aluminium-Eriochrome-cyanine complex,452 andaluminium-chrome azurol-S complex.453 Methods based on the formationof silicomolybdate have been used for the photometric determination ofsilicate.511~ 512 Nitrite ion has been determined by reaction with“ Rivanol ” 48 (2 : li-diamino-’l-ethoxyacridine), and nitrate ion by reactionwith aniline acetate.513 Tetrathionate has been determined by reactionwith cyanide to form thiocyanate and subsequent application of the ferric-thiocyanate reaction.514 Bromide has been determined by conversion intotetrabromofluorescein, 515 and sulphate ion by reaction with 4-amino-4’-~hlorodiphenyl.~~~ Iodine has been determined by its redox reaction withVariamin-blue-B 517 (4-amino-4’-methoxydiphenylamine). The colorimetricdetermination of minute amounts of phosphoric, arsenic, silicic, and germanicacids has been effected by extraction of their molybdate complexes withvarious water-immiscible solvents. 518 Boron has been determined inuranium, graphite, and beryllia by the curcumin reaction,519 by formationof the poly(viny1 alcohol)-borate-iodine by a method based onthe acceleration by boric acid of the reaction between H-acid and salicyl-aldehyde,520 by reaction with two new reagents, viz., 5-benzamido-6’-chloro-1 : 1’-dianthrimide and 5-$-toluidino-l : l’-dianth~-imide.~~ Traces of oxy-gen in solution have been determined with reduced indigo-~armine,~~’ andin gases by reaction with reduced sodium anthraquinone-2-sulphonate.522High dilutions of ozone have been determined by reaction with potassiumiodide.523 The accurate absorptiometric determination of pH within *O.Olbo2 W. M. Wise and W. W. Brandt, Analyt. Chem., 1955, 27, 1392.503 A. I. Ponomarev and L. L. Ratina, Zavodskaya Lab., 1955, 21, 918.504 S.Hirano and T. Fukazawa, Japan Analyst, 1955, 4, 616.505 V. Patrovsky, Chem. Listy, 1955, 49, 854.506 G. Almkssy and 2. Nagy, Acta Cltim. Acad. Sci. Hung., 1955, 6, 339.507 M. Q. Freeland and J . S. Fritz, Analyt. Chem., 1955, 27, 1737.508 E. D. $hall and H. G. Williamson, J . Ass. O#. Agric. Chem., 1955, 38, 454.500 K. Emi and T. Hayami, J . Chena. SOC. Japan, Pure Chem. Sect., 1955, 76,510 J . J . Lothe, Analyt. Chem., 1956, 28, 949.511 E. Blasius and A. Czekay, Z. analyt. Chem., 1955, 147, 1.j 1 2 K. Jordan and R. W. Fisclier, Tech. Mitt. Krupp, 1055, 13, 39.513 T. Kato, Y. Okinaka, and K. Sakai, Japan Analyst, 1954, 3, 231.614 0. A. Nietzel and M. A. De Sesa, Analyt. Chem., 1955, 27, 1839.515 I?. A. Pohl, 2. analyt. Chem., 1956, 149, 68.516 A.S. Jones and D. S. Letham, Analyst, 1956, 81, 15.617 L. Erdey and F. SzabadvBry, Acta Chim. Acad. Sci. Huwg., 1955, 8, 191.518 T. Kiba and M. Ura, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 520.510 J. Coursier, J. Hure, and R. Platzer, Rapp. Centre &at, Nucl. Saclay, 1955, No.520 L. M. Kul’berg and T. I. Badeeva, Ref. Zhur., Khim., 1955, Abstr. No. 14,240.521 L. S. Buchoff, N. M. Ingber, and J. H. Brady, Analyl. Chem., 1955, 27, 1401.522 C. Stafford, J. E. Fuckett, M. D. Grimes, and R. J. Heinrich, ibid., p. 2012.623 J. N. Pring, .I. , 4 p p l . ChPnt., 19.55, 5, 888.1291.404368 ANALYTICAL CHEMISTRY.unit has been described.524 The use of a considerable range of new colori-metric reagents has been reviewed by Stephen.49Instrumental Methods of TitrationPhotometric Titration.-The use of a photoelectric cell and the narrowwave-band of a spectrophotometer in place of the human eye for the detectionof the end-point in titrimetric procedures appears to have found less applic-ation during the past year.Bobtelsky and his co-workers have continuedtheir studies in heterometric titration. In this technique measurement ofthe changes in absorption of a finely suspended precipitate reveals theposition of the end-point. The fundamentals of the method have beenreviewed.525 The technique has been applied to the determination of copperwith ~alicylaldoxirne,~~~ calcium in the presence of excess of magnesium with~ u l p h a t e , ~ ~ ~ mercury with diethyldithi~carbarnate,~~~ and in the presence ofmany other metals which can be sequestered by means of ethylenediamine-tetra-acetic acid,529 sulphuric acid with barium r~itrate,~SO copper by diethyl-dithiocarbamate 531 in the presence of many other metals, iron with aluminonin the presence of other metals including aluminium.532 Spectrophotometricend-points have been used in the titration of various ions with a tervalentcobalt titrant 533 and also in the titration of chromate and vanadate by meansof ferrous sulphate and arsenious oxide.534High-frequency Titration.-The continued growth of interest in the useof high-frequency methods of titration is largely reflected by the number ofpapers dealing with fundamental aspects and instrumentation.Studies onconcentration curves with a capacitance-type instrument have been re-ported 535 and a simple heterodyne-type apparatus has been described.536Others have described a stable high-frequency apparatus operating in the100 Mc frequency range.537 High-frequency instrumentation has beengenerally reviewed with particular reference to cell In aninvestigation into the fundamental aspccts of high-frequency titration, theeffect of shielding the solution has been Another type of high-frequency titrimeter has been described,=O and the application of the methodto the titration of halides, etc., in pyridine solution has been investigated.%l524 G. Monod-Herzen, Compt. rend., 1955, 240, 2146.525 M. Bobtelsky, Analyt. Chim. Actn, 1955, 13, 172.526 M. Bobtelsky and E. Jungreis, ibid., p. 449.527 M.Bobtelsky and J. Eisenstadter, ibid., 1956, 14, 89.528 M. Bobtelsky and R. Rafailoff, ihid., p. 247.5z9 Idem, ibid., p. 339.530 M. Bobstelsky and J. Eisenstadter, ibid., p. 189.531 M. Bobstelsky and R. Rafailoff, ibid., p. 558.532 M. Bobtelsky and A. Ben-Bassat, itid., p. 439.533 R. Maurodineann and J. Wrtsman, Centr. Bo-yce Thompson Inst., 1955, 18, 181.534 J. W. Miles and D. T. Englis, Analyt. Chem., 1955, 27, 1906.535 Y. Kamura, Pharm. Bull. Japan, 1955, 3, 138.536 N. Nakamura, Japan Analyst, 1955, 4, 345.537 A. H. Johnson and A. Timnick, Analyt. Chem., 1956, 28, 889.538 J. C. Clayton, J. F. Hazel, \V. M. McNabb, and G. L. Schnable, Analyt. Chim.539 K. Nakano, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1096.640 J.C. Clayton, J. F. Hazel, W. M. McNabb, and G. L. Schnable, Analyt. CJzim.5 4 ' J . P. Young, Diss. Abs., 1956, 15, 1302.Acta, 1956, 14, 269.Acta, 1965, 13, 487BELCHER, SHERIDAN, STEPHEN, AND WEST. 369The titration of various organic bases, phenols, and enols has beendescribedea2 The high-frequency titration of phenols forms the subjectof another communication.m The technique has been used for the titrationof sulphur in rubber vulcanisers 544 and for the complexometric titration ofthorium 545 and the rare earths.H6Codometric Titration.-A high-precision coulometric titrator has beendescribed,547 and also an instrument with a low inertia electromechanicalmotor to integrate current and time.54s The application of the technique tomicro-volumes of solution has also been d e ~ c r i b e d .~ ~ Thallium has beendetermined by coulometric titration with f e r r i ~ y a n i d e , ~ ~ ~ titanium withceric ion,551 various oxidised ions by quadrivalent uranium, 552 uranyl ionwith titanous ion,553 various metals with EDTA,554 ammonia withh y p ~ b r o r n i t e , ~ ~ ~ arsenic(II1) with ceric ferric iron with EDTA,557and halides with mercurous 558 and mercuric ion.559 Carbon in steels andcarbides has been determined by potentio-coulometric t i t r a t i ~ n . ~ ~ ~ Quinolhas been titrated coulometrically with iodine,561 and various organic basesin acetonitrile by anodic generation of hydrogen ion from the moisturecontent of the solvent.563Dead-stop End-point Titrations.-Very little use appears to have beenmade of this technique during the period covered by the Report.A tran-sistor amplifier for dead-stop end-points has been described. 563 Factorsinfluencing the flow of current in dead-stop end-point titrations have beeninvestigated and discussed. 564 Cobalt (111) has been titrated with ferroussulphate, and dichromate in the presence of excess of t ~ n g s t a t e . ~ ~ 5 Smallquantities of chloride have been titrated by using silver nitrate and a silver-silver (or gold) amalgam electrode system. 566 Formaldehyde has beentitrated by dead-stop end-point technique, hydroxylamine hydrochloridebeing the titrant.567 The technique has been applied to the acidimetric542 E. S. Lane, Analyst, 1955, 80, 675.543 E. T. Lippmaa, Zhatr.analit. Khim., S.S.S.R., 1955, 10, 169.5‘4 I. Yamaji, Rep. Tokyo Chewz. Ind. Res. Inst., 1955, 50, 203.s45 R. Hara and P. W. West, Analyt. Chim. Acta, 1955, 13, 189.546 Idem, ibid., 1956, 14, 280.547 G. E. Gerhardt, H. C. Lawrence, and J. S. Parsons, Aizalyt. Chem., 1955, 27, 1752.J. S. Parsons, W. Seaman, and R. M. Amick, ibid., p. 1754.549 R. Schreiber and W. D. Cooke, ibid., p. 1475.550 A. M. Hartley and J. J . Lingane, Analyt. Chim. Acta, 1955, 13, 183.551 R. V. Dilts and N. H. Furman, Analyt. Chem., 1955, 27, 1596.552 W. D. Shults, P. F. Thomason, and M. T. Kelley, ibid., p. 1750.553 J. J. Lingane and R. T. Iwamoto, Analyt. Chim. Acta, 1955, 13, 465.554 C. N. Reilley and W. W. Porterfield, Analyt. Chem., 1956, 28, 443.555 G.M. Arcand and E. H. Swift, ibid., p. 440.556 N. H. Furman and A. J. Fenton, ibid., p. 515.6 5 7 R. W. Schmid and C. N. Reilley, ibid., p . 520.558 D. D. DeFord and H. Horn, ibid., p. 797.559 E. P. Przybylowicz and L. B. Rogers, ibid., p. 799.5130 &I. Sicha, H u h . List., 1955, 10, 535.561 I. Bajalovid and K. NikoliC, Bull. SOC. chim. Beograd, 1955, 20, 329.5 6 2 C. A. Streuli, Analyt. Chem., 1956, 28, 130.5G3 J. B. Phillips, Chemist-Analyst, 1955, 44, 80.864 H. L. Kies and T. S. Hein, 2. analyt. Chem., 1966, 148, 91.565 I;. C. W. Baker and T. I-’. McCutcheon. Analyt. Chem., 1955, 27, 1625.5 6 G I?. ill. Deschamps, Bull. Soc. chinz. Frame, 1956, 126.5 6 7 E. SGrebenovskq and 2. Rezar, Chem. Listy, 1355, 49, 1155370 ANALYTICAL CHEMISTRY.and alkalimetric titration of various substances in methanolic, ethanolic, andbutanolic s0lution.~68Conductometric Titration.-Relatively little use has been made of thistechnique during the year.A Russian worker has described an instrumentin which the platinum electrodes of the conductance cell are connected inseries with the lamp of a photo-coiorimeter. The photo-current read on thegalvanometer is proportional to the third power of the change of the voltageof the current to the lamp.569 Conductometric titrations using directcurrent have been described by others. 570 A low-frequency electrodelessconductometer has been described. 571 A conductometric method for thedetermination of phenolic groups in mixtures such as isolated lignins hasbeen reported.572 Certain alkaloids have been determined ~ i m i l a r l y , 5 ~ ~naphthalene-2-sulphonic acid in acetone being used as titrant. The con-ductometric determination of alkali sulphide, hydroxide, and carbonate inthe presence of each other by use of silver nitrate as titrant has been de-scribed. 574 Nickel sulphate, nickel sulphate and sulphuric acid, and nickelsulphate in the presence of sodium sulphate and sulphuric acid have beendetermined by conductometric titration with barium hydroxide. 575 Ex-change cations in clays have been titrated conductometrically with standardhydrochloric acid. 576Potentiometric Titration.-Various devices for automatic potent iome t rictitration have been described 577 and particular attention has been devotedto the selection of electrode systems for use with automatic differentialpotentiometric titrators in aqueous and non-aqueous systems. 578 Investig-ations have been conducted into the oxidation of the surface of platinumelectrodes during redox titrations.The data obtained indicate that thisphenomenon can explain the occurrence of drifting p0tentials.5~~ The glasselectrode has been used as reference electrode in the titration of sodium ionswith zinc uranyl acetate in 85-95% ethanolic solution.580 (The glasselectrode was fabricated from Jena-20 glass.) Other workers have used anindicator glass electrode for the titration of thorium nitrate in 0.001~-solution with 0.01 M-ammonium or sodium oxalate. Four inflections occur.At the first equivalence point, pH 4.3, thorium oxalate is precipitated; theother three between pH 5.4 and 6.3 correspond to thorium oxalate com-p l e x e ~ .~ ~ ~ Several typesof tellurium electrode for acid-base titrations have been examined.582Cerium behaves in a manner similar to thorium.5 6 8 G. Mann, Magyar Kkm. Folydirat, 1955, 61, 26.569 M. I. Kulenok, Zavodskaya Lab., 1955, 21, 1027..i70 J. DCvag and E. Miihlrod, Magyar Kkm. Folydivat, 1956, 62, 153.. j i 1 M. Salamon and 1’. Svitok, Chem. pvumsyl, 1956, 6, 10.5 7 2 K. Starkanen and C. Schuerch, Analyt. Chem., 1955, 27, 1245.573 V. V. Udovenko and L. L. Vvedmskaya, Uhrain. khim. Zhur., 1954, 20, 684.574 R. DomanskL, Chem. Lisly, 1955, 49, 186.5 i 5 M. 1 . [Jsanovich, 2. P. Yakusheva, and S.V. Lebedeva, Ref. Zhur., Khim.,576 2. P. Yakusheva, ibid., Abstr. No. 14,269.5 7 7 R. Audran and D. T. R. Dighton, J. Sci. rnstr., 1956, 33, 92.5713 H. V. Malmstadt and E. R. Fett, Analyt. Chem., 1955, 27, 1767.579 J . W. Ross and I. Shain, ibid., 1956, 28, 548.58O 0. Tomieek and R. Pulpan, Chem. Listy, 1965, 49, 497.j 8 1 K. Pan and T. M. Hseu, Bull. Chem. SOC. Japan, 1955, 28, 309.5p2 A . R . Tourky, 1. M. Tssa, and S . A. Awad. Chim. nnnlvf., 2966, 37, 367.1955, Abstr. KO. 23,981BELCHER, SHERIDAN, STEPHEN, AND WEST. 37 1Variations in the sensitivity of the bromine-bromide end-point have beenexamined with relation to electrode surface area, rate of stirring, magnitudeof potentiometer current, e t ~ . ~ ~ ~ The dependence of the E.M.F. of 12bimetallic electrode systems on the pH has been studied.The systemsTe-Ag, Te-Au, Te-graphite, Sb-Ag, and Sb-Au have hitherto not beendescribed in the l i t e r a t ~ r e . ~ ~Zinc has been determined in ores by the ferrocyanide t i t r a t i ~ n , ~ ~ ~ andcadmium has been titrated with lithium ferro~yanide.~~~ Ascorbic acid hasbeen used as titrant in the potentiometric determination of gold,587 iron,copper, and vanadate. 588 Iron has been titrated potentiometrically withquinquevalent Sexavalent tungsten has been titrated withchromous chloride.590 Dithio-oxamide has been used as titrant for thedetermination of copper 591 with a silver indicator electrode; EDTA, bis-hydroxyethylglycine, and nitrilotriacetic acid as titrants for various cationsusing several electrode systems; 592 manganous ion as titrant for per-manganate ions ; 593 mercuric chloride as titrant for cystine and cysteine,594amalgamated gold electrodes being used.A rapid argentometric deter-mination of the halides by direct potentiometric titration has been de-described. 595 Sulphur trioxide in concentrated sulphuric acid has beentitrated directly with water.596Non-aqueous TitrationsThe topic of non-aqueous titration has been generally revie~ed.~~’l 598The use of the high-frequency method for end-point detection has beendiscussed.=l Polish workers have described a special silver-silver chloridereference electrode for use in non-aqueous procedures. 599 New bimetallicelectrode systems for potentiometric acid-base titrations in non-aqueoussolutions have been described.600 The solvent systems examined in thisinvestigation were methanol and glacial acetic acid.A platinum-silversystem was preferred for the former medium, and graphite used withtungsten, gold, antimony, silver, platinum, or tellurium was successfulin the latter solvent. A spectrophotometric and potentiornetric studya3 W. C. l’urdy, E. A. Burns, and L. B. Rogers, Analyt. Chem., 1955, 27, 1988.584 V. Novdk, Chem. Listy, 1955, 49, 934.585 M. I. Troitskaya and N. F. Sarayeva, Ref. Zhur., Khim., 1956, Abstr. No. 4140.A. Basinski and M. Lango, Przemysl Chem., 1955, 11, 145.j B i N. K. Pshenits9n and S. I. Ginsburg, Ref. Zhur., Khim.. 1956, Abstr. No. 1104.C. Yoshimura and T. Fuzitani, J . Chem.Soc. Japan, Pure Chew. Sect., 1955,6*n ‘I. M. Issa and A. M. Daess, Chemist-AnaZyst, 1955, 44, 89.j 9 0 I. Muraki, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 193..jgl V. W. Meloche and L. Kalbas, Analyt. Chem., 1956, 28, 1047.jg2 S. Siggia, D. W. Eichlin, and R. C. Reinhart, ibid., 1955, 27, 1745.5B3 I. M. Issa and R. M. Issa, Chemist-Analyst, 1955, 44, 99.jY4 R. Cecil, Biochiw. Biophys. Acta, 1955, 18, 154.;y5 V. J. Shiner and M. L. Smith, AnaZyt. Chem., 1956, 28, 1043.JBi J. Capilla-Rufias and L. GimCnez-EstellCs, Inf. Quim. Anal., 1955, 9, 129.jY* A. H. Beckett and E. H. Tinley, “ Titration in Non-aqueous Solvents,” Rlessrs.SR9 J . Minczewski and 2. Lada, Hoczniki ClLem., 1955, 29, 919.76, 304.H. B. van der Heijde, Chem. Weekblad, 1955, 51, 823.H.D.H., Ltd., Poole, 1956.V.NOV~C, Chenz. L i s t v , 1955, 49, 848372 ANALYTICAL CHEMISTRY.has been made of the behaviour of some thirteen acid-base indicators inan acetic acid solvent system.601 Vanadyl acetate has been used in glacialacetic acid as an amperometric titrant; 602 its application to an inorganicdetermination is described. The use of chelating agents in non-aqueoustitrimetry has been described. An aqueous solution of the metal ionsis evaporated to dryness and treated with methanol and a suitable chelat-ing agent. The hydrogen ion liberated is titrated subsequently withstandard sodium hydroxide In benzene-methanol. 603 The scope of phenol-chloroform-acetonitrile as a solvent system for the salts of organic bases hasbeen examined; 604 perchloric acid in dioxan was used as titrant.Lithiumhas been determined by direct application of the Volhard method to a 2-ethyl-hexanol extract of lithium chloride.605 Potassium has been determined fol-lowing precipitation of its insoluble tetraphenylboron salt by non-aqueoustitrimetric methods in anhydrous acetone 606 and in aqueous acetone-607Compounds containing positive chlorine or bromine have been titrated withsulphur dioxide in pyridine.608 Ammonium hexanitratocerate in glacialacetic acid has been used as titrant for oxalic acid in the sameOrganic bases have been titrated in benzene and methanol with diphenylphosphate as titrant, both potentiometric and visual end-points being usedwith several indicators.610 Weak bases related to nitroguanidine have beentitrated with methoxide in dimethylformamide and ethylenediamine, andwith perchloric acid in trifluoroacetic acid.611 Basic co-polymers of acrylo-nitrile have been titrated in a mixture of nitromethane and formic acid.612Sulphonamides have been titrated in methanol-benzene and pyridine withperchloric acid,G13 morphine, its derivatives, and their acid salts in glacialacetic acid with perchloric a~id,~14 and antihistamine drugs by the samer n e t h ~ d .~ l ~A comprehensive review of methods of titrating weak acids in non-aqueous solvents has been published, the merits of various indicators beingdescribed in detail.616 An anodically polarised platinum wire has been usedas indicator electrode for the titration of very weak acids in ethylenediamine.The reference electrode was a short length of platinum wire inserted into thestream of the titrant.617 Phenols have been titrated in a composite diethyl-amine-pyridine-diethylformamide-thymol solvent by using a conventional601 T.Higuchi, J. A. Feldman, and C. R. Rhem. Analyt. C b m . , 1966,28, 1120.Bo2 J. Novotny, Chem. Listy, 1954, 48, 1865.603 B. D. Brummet and R. M. Hollweg, A.naZyt. Chem., 1956, $38. 448.604 L. G. Chatten, J . Pharwz. PharmacoZ., 1955, 27, 586.605 J. C. White and G. Goldberg, Analyt. Chein., 1955, 27, 1188.606 H. Flaschka, Chemist-Analyst, 1955, 44, 60.608 R. W. Freedman, Analyt. Chem., 1956, 28, 247.609 0. N. Hinsvark and K. G. Stone, ibid., p. 334.6 1 1 J. E.De Vries, S . Schiff, and E. St. C. Gantz, Analyt. Chem., 1955, 27, 1814.612 C. A. Streuli, ibid., p. 1827.Y . Tajika and M. Aikawa, J . Pharm. SOC. Japan, 1954, 74, 1125.614 T. Kashima, A. Asahina, and Y . Shiuchi, ibid., 1955, 75, 329.6 1 5 T. Kashima, ibid., p. 332.K. Backe-Hansen, Med. norsk. Favm. Selsk., 1955, 17, 282.G. A , IIsrlow, C. M. Noble, and G. E. A. Wyld, Analyt. Chem., 1956, 28,H. W. nerkhout and G. H. Joogen, Chem. WeeRbZad, 1955, 51, 607.M. M. Davis and H. B. Hetzer, J . Res. Nut. BUY. Stand., 1956, 54, 309.784BELCHER, SHERIDAN, STEPHEN, AND WEST. 373methoxide titrant and potentiometric detection of the end-point.618 4-Amino-4'-nitroazobenzene has been described as a new indicator for thetitration of phenols in ethylenediamine and pyridine : the red-blue colourtransition is claimed to be very sensitive.619 Various hydroxyanthra-quinones have been titrated in pyridine with sodium methoxide and use of aglass-antimony electrode pair.620 A glass-calomel system and thymol-bluehave been used in the titration of cholic, deoxycholic, and dehydrocholicacids in benzene-methanol or chloroform-dimethylformamide.621 Carb-oxylic acid anhydrides have been determined by reaction with excess ofmorpholine and titration of unreacted base with methanolic hydrochloricacid.622 Tetrabutylammonium hydroxide has been used as a titrant forweak acids in the usual basic solvents, ketones, alcohols, etc.It appears topossess several advantages over potassium methoxide.6s* 624Flame-photometryA general trend is now apparent in which many authors are attempt-ing to extend the scope of the flame-photometry method beyond the usualrange of alkali and alkaline-earth metals.Aluminium has been deter-mined indirectly by its damping effect on the intensity of the 423, 554,and 622 mp calcium lines : 6z5 it can thus be determined in zinc die-castingalloys. Silver has been determined in the presence of cadmium andzinc by using the intensity of the 338 mp line in an oxy-hydrogen flame.Acetone was added to the hydrochloric acid spray to increase sensitivity."GResults have been reported for the analysis of nickel, cobalt, manganese,and chromium in steel after a preliminary removal of bulk iron by solventextraction. The method is not as accurate as chemical procedures, butis rapid and permits simultaneous determination^.^^' Flame-emissionmeasurements at 540 mp permit the determination of phosphorus in organo-phosphorus compounds in ethanolic solution within the concentrationrange 0 - 0 1 4 - 0 3 ~ with an average error of 0 .0 0 0 6 ~ ~ ~ ~ ~ Manganese may bedetermined by measurements at 403-3 mp.629 The analysis of manganesein cement is thus made possible.630 An oxy-acetylene flame with measure-ment at 2860 A has been used for the determination of iron in siliceousmaterials.g31 The iron may be separated from other interfering metals innon-ferrous alloys by acetylacetone extraction and fed directly into an oxy-acetylene flame for measurement at 3720A. Moderate amounts of alu-618 E.T. Lippmaa, Zhur. analit. Khim., 1955, 10, 169.619 K. Takiura and Y . Takino, J . Pharm. SOC. Japan, 1954, 74, 971.620 A. Anastasi, U. Gallo, and E. Mecarelli, Mikrochim. Acta, 1956, 252.621 R. Crisafio and L. G. Chatten, J . Amer. Pharm. Assoc., Sci. Ed., 1955, 44, 529.622 J. B. Johnson and G. L. Funk, Analyt. Chem., 1955, 27, 1464.623 G. A. Harlow, C. M. Noble, and G. E. A. Wyld, ibid., 1966, 28, 787.624 R. H. Cundiff and P. C. Markunas, ibid., p. 792.625 J. Kashima and &I. Rlutaguchi, Japan Anai-vst, 1955, 4, 420.6 2 6 A. 0. Rathje, Analyt. Chem., 1955, 27, 1583.cj27 F. Burriel-Marti, J. Ramirez-Muiioz, and M. C. Asuncion-Omarrementeria,628 D. W. Brite, Andy#. Chem., 1955, 27, 1815.629 W. A. Dippel and C. E. Bricker, ibid., p.1484.830 J. J. Diamond, ibid., 1956, Rs, 328.c31 J. A. Dean and J. C. Burger, ibid., 1965, 27, 1052.Mikvochim. Acfa, 1856, 362374 ANALYTICAL CHEMISTRY.minium, copper, and nickel do not interfere, and the presence of the acetyl-acetone amplifies (about 6-fold) the sensitivity of the 3720 A line.a2 Tetra-ethyl-lead in petrol may be determined by measurement of the intensity ofthe lead 406 m p line in an oxygen-hydrogen enriched flame.633 Magnesiumhas been determined by the flame-photometric method in aluminium,634 inand in plasma after a preliminary separation with 8-hydroxy-q ~ i n o l i n e . ~ ~ ~ The interference of various cations and anions with themagnesium method has been s t ~ d i e d . ~ ' The determination of rubidiumand caesium in the presence of sodium and potassium has been described.e8Many papers are concerned with the determination of the alkali metals 639-644and alkaline-earth The influence of co-solutes in general hasbeen studied 656 and a few papers deal with aspects of in~trumentation.~~~~ 658Flame spectrograms for eighteen common elements have been publishedby two American and of twenty metals by other Americanworkers.660 In both cases the Beckman D.U.spectrophotometer with thephotomultiplier phototube in place of the usual phototube was used asrecording instrument.Ion-exchange Met hodsThe applications of ion-exchangers to inorganic analysis have beenreviewed and g62 and the selectivity and specificity of variousresins examined.6a The elution constants of last traces of metals from an632 J.A. Dean and J. H. Hardy, Analyt. Chem. 1955, 27, 1533.638 W. Meine, Erdol u. Kohle, 1965, 8, 711.634 S. Ikeda, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1122.J. F. P. de Albinati, Anales Asoc. qulm. argentina, 1955, 43, 106.636 S. Davies, J . Biol. Chem., 1956, 216, 643.e3' E. Pungor and I. Konkoly-Thege, Magyar Kim. Folydirat, 1956, 61, 17.638 M. J. Pro, R. A. Nelson, and A. P. Mathers, J . Assoc. OH. Agric. Chem., 1966,639 H. F. Hourigan and J. W. Robinson, Analyt. Chim. Ada, 1965, 13, 179.R40 S. Ikeda, J . Chem. SOC. Japan, Pure Chem. Sect., 1965, 76, 354.641 F. Hegemann and B. Pfab, GEastech. Ber., 1965, 28, 86.642 E. Pungor and E. 8. Zapp, Acta Chim. Acad. Sci. Hung., 1955, 7, 186.641 N.Roy, Analyt. Chem.. 1956, 28, 34.646 F. Reich and F. Grabbe, Tonindustr. Ztg., 1965, 79, 127.646 S. Yokosuka, M. Tanaka, and H. Morikawa, Japan Analyst, 1955, 4, 437.647 E. Pungor and A. Hegediis, Magyar Kkm. Folydirat, 1955, 61, 308.d48 C. F. Rothe and L. A. Saperstein, Amer. J . Clin. Path., 1956, 25, 1076.6J9 I. MacIntyre, Rec. Trav. chim., 1965, 74. 498.G50 R. W. R. Baker, ibid., p. 602.8 5 1 H. J. Dulce, 2. physiol. Chem., 1955, 802, 102.669 S. Ikeda, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1258.6L3 M. J. Pro and A. P. Mathers, J . Assoc. Ofic. Agric. Chem., 1956, 89, 225.1x4 G. W. Standen and C. B. Tennant, Analyt. Chem., 1956, 28, 868.6 5 5 S. Yokosuka, Japan Analyst, 1956, 5, 74..iii6 J. Fischer and A. Doiwa, Mikrochim.Ada, 1966, 353.6 5 7 B. L. Valee and M. Margoshes, Analyt. Chem., 1966, 28, 175.8 5 8 Idem, ibid., p. 180.659 H. Watanabe and K. K . Kendall, Appl. Spectroscopy, 1955, 9, 132.660 M. Whisman and B. H. Eccleston, Analyt. Chem., 1956, 27, 1861.G 6 L J. Marc6 Piera, Ajinidad, 1966, 32, 47.662 0. E. Schultz, J . Pharm. Pharmacol., 1966, 8, 382.13~3 R. Greissbach, Angear. Chem., 1966, 67, 606.39, 506.Idem, Magyar Kkm. Folydirat, 1955, 61, 421BELCHEK, SHERIDAN, STEPHEN, AND WEST. 376exchange resin (Wofatit L) have been investigated. 664 Critical values forquantitative separations of various cations on this resin have been studiedby the same author and his co-worker.665 Ion-exchangers have been usedin ethanol 666 and acetone.667 A redox resin has been used for the removalof oxygen from aqueous solution.668 Ion-exchange resins have been usedin the desalting of amino-a~ids,~~~ in the separation of antihi~tarnines,~~~ inthe preparation of O .l ~ - a c i d , ~ ~ ~ and in the preparation of silicon-free alkalifor use in silicon analyses.672Ion-exchange resins have been used in the separation of several ions , viz.,niobium and tantalum,673 zirconium and hafnium,674 cadmium, zinc, andcopper,675 cadmium and zinc from other metals,676 calcium and aluminiumfrom iron,677 iron, chromium, manganese, and molybdenum andphosphate and arsenate from cations,680* 681 aluminium fromfluoride,682 thallium and indium,683 rare earths, 684 fluoride from otheranions,685 lead from fluoride,686 mixtures of condensed phosphates,6s7 andzinc from several metals including cadmium, gallium, and indium.688 Zinchas been determined in aluminium alloys 689 and in ferrites in the presence ofnickel after ion-exchange separation.690 Molybdenum in steels has beendetermined after removal of interfering elements by ion-exchange treat-ment.691 Sulphur has been determined after ion-exchange isolation inmaterials such as pyrites 692 and pigments, etc.693 Potassium has beendetermined by dissolving the precipitated tetraphenylboron salt in acetoneand titration of the tetraphenylboron acid released by a cation-exchanger inthe hydrogen form.694 Free acid in ceric solutions may be determined by864 D. Jentzsch, 2. analyt. Chem., 1955, 148, 321 and 325.88s D. Jentzsch and I.Pawlik, ibid., 1955, 147, 20.668 K. K. Caroll, Nature, 1955, 176, 398.867 H. Kakihana and K. Sekiguchi, J . Pharm. SOC. Japan, 1955, 75, 111.668 G. Manecke, Angew. Chem., 1955, 67, 613.669 G. C. Mueller, G. Bowman, and A. Herranen, Analyt. Chem., 1955, 27, 1357.670 S. M. Blaug, Diss. Abs., 1955, 15, 983.1 3 7 ~ S. Hirano and M. Kurobe, Japan Analyst, 1955, 4, 379.672 S. Fisher and R. Kunin, Nature, 1956, 177, 1125.673 M. J. Cabell and I. Milner, Analyt. Chim. Acta, 1955, 13, 258.674 K. S. Rajan and J . Gupta, J . Sci. Ind. Res. India, 1955, B, 14, 453.675 Y. Yoshino and M. Kokima, Japan Analyst, 1955, 4, 311.676 S. Kallmann, C . G. Steele, and N. Y . Chu, Analyt. Chem., 1956, 28, 230.677 0. Samuelson and B. Sjonberg, AnaZyt. Chim.Acta, 1956, 14, 121.678 D. I. Rybachikovand V. F. Osipova, DokZady Akad. Nauk S.S.S.R., 1954,96, 761.67s T. Matsuo and A. Iwase, Japan Analyst, 1955, 4, 148.OB0 Y. Yoshino, ibid., 1954, 3, 121.881 Sh. T. Talipov and T. I. Fedorova, Ref. Zhur., Khim., 1955, Abstr. No. 26,501.682 J. Coursier and J . Saulnier, Analyt. Chim. Ada, 1966, 14, 62.683 L. B. Ginzburg and g . P. Shkrobot, ZavodsRaya Lab., 1955, 21, 1289.684 W. E. Nervik, J . Phys. Chem., 1955, 59, 690.685 W. Funasaka, M. Kawase, T. Kojima, and Y. Matsuda, Japan Analyst, 1955,6a6 C. Mader, Chemist-Analyst, 1955, 44, 86.687 T. V. Peters and \Y. Rieman, Analyt. Chim. Acta, 1956, 14, 131.6 8 8 J. A. Hunter and C. C. Miller, Analyst, 1956, 81, 79.080 K. Kodama and T. Kanie, Japan Analyst, 1955, 4, 627.690 J .Lowen and A. I,. Carney, Analyt. Chem., 1955, 27, 1966.691 I. P. Alimarin and A. M. Medvedeva, Zavodsliaya Lab., 1955, 21, 1416.892 S. Hirano and M. Kurobe, Japan Analyst, 1955, 4, 552.693 S. Hirano, M. Kurobe, and F. Ito, ibid., p. 565.894 H. Flaschka and F. Sadek, Chemist-AnnZyst, 1956, 45, 20.4, 514376 ANALYTICAL CHEMISTRY.cation exchange and deduction of the acid corresponding to the ceric ionknown to be present.695 The application of a cation-exchange resin t o theanalysis of a bronze has been described.606The reduction of ferric and cupric ions adsorbed on a cation resin bysolutions of iodide has been and the detection of germaniumby means of a resin saturated with haematoxylin has been des~ribed.~~8 Thereactions occurring between chromic complexes and cation-exchange resinshave been investigated.G99Inorganic ChromatographyThe practice, technique, and theory of inorganic paper-chromatographyhave been reviewed.700* 701 The behaviour of various cations and theircounter-ions has been examined.702 Other workers have studied factorsaffecting RF and S values with impregnated filter-papers 7w and the r81eof the hydrogen-ion concentration of solvents in inorganic paper-chromato-graphy. 704 The rates of migration of cations during paper-chromatographyunder varying conditions have been studied.705 A new method for cationsof the first group [Ag, Pb, H~(I)] has been described,706 and also a modifiedtechnique for general application to inorganic work.707 German workershave investigated the chromatography of various electrolytes on silica gel.708The location of acid zones on paper strips has been studied with particularreference to organic acids, but the method may also be applied to weaklydissociated inorganic acids.709 A method of precipitation chromatographyon filter-paper impregnated with 8-hydroxyquinoline has been used for thedetection of copper, iron, cobalt, and nickel.710 American authors haveoutlined a method and procedure for the partial acetylation of paper forchr~matography.~~~ The RF values for over forty metal ions, by paper-chromatography with butanol saturated with aqueous molar solutions ofvarious organic complexing acids, have been listed. 712 Yugoslav authorshave published a new method for the separation of certain cations withvarious solvent systems.713 The paper-chromatography of metal chelate695 V. V. Oshchapovskii, Ukrain. khim. Zhur., 1955, 21, 384.696 V. I. Lenskaya and L. I. Penkova, Ref. Zhur., Khim., 1956, Abstr. No. 14,268.697 H. Kakihana and K. Katou, J . Chem. SOL. Japan, Pure Chem. Sect., 1955, 76, 499.698 H. Kakihana, Y. Mori, and K. Yamasaki, ibid., p. 215.699 Y. Inoue, A. Kawamura, K. Wada, and H. Okamura, Japan Analyst, 1955, 4,700 J. Moreno Calvo, Rev. Cienc. apZ., 1955, 9, 510.?O1 M. Lederer, Mikrochim. Ada, 1956, 43.702 S. Harasawa and T. Sakamoto, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76,703 A. C. Chatterji and H. Bhagwan, Z. analyt. Chem., 1956, 149, 339.704 G. Alm&ssy and I.Dezso, Magyar Kkm. Folydirat, 1956, 82, 60.705 G. Sommer, 2. analyt. Chern., 1955, 147, 241.706 K. Suzuki, J . Chem. SOC. .Japan, Pure Chem. Sect., 1955, 76, 184.707 K. Krislinamurti and B. V. Dhareshwar, Research, 1955, 8, 526.7 0 8 F. Umland and K. Kirchner, 2. anorg. Chem., 1955, 280, 211.709 A. L. Cochrane, Analyst, 1955, 80, 909.710 H. Nagai, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76, 1246.7 1 1 E. hI. Buras and S. R. Hobart, Analyt. Chem., 1955, 27, 1507.712 J . R. A. Anderson and E. C. Martin, Analyt. Chim. Acta, 1955, 13, 253.713 G, StefanoviC, IF. Janjik, and R. Crnojevid, Bull. SOC. chim. Beograd, 1955, 20, 343.277 and 281.1322BELCHER, SHERIDAN, STEPHEN, AND WEST. 377compounds of the P-diketones, acetylacetone, 714 and 2-thenoyl- and 2-furoyl-perfluorobutyrylmethane has been reported.715 Japanese workers havedescribed the application of some organic reagents , viz. , phenylthiosemi-carbazide, gallein, and thiogallein a s detection reagents for metals on paper-chromatograms. 716 The chromatographic separation of different elements indifferent valency states has been studied.717The separation of polythionic acids 718+ 719 and of condensed phos-phates 7209 721 has been studied fairly extensively. Paper-chromatographicmethods have been described for the separation and determination of verymany metals. Thus methods have been described for : the rare earths; 722nickel in cobalt salts ; 723 nickel and cobalt ; 724 cobalt and copper; 725cobalt(II1) compounds ; 726 platinum metals ; 727 lead, mercury, bismuth,copper, and cadmium ; 728 arsenic ; 729* 230 copper and methods for assessingit on paper; 7319 732 boron in the presence of the Group I metals; 733uranium ; 734-736 the alkali and alkaline earths ; 737-741 germanium ; 7429 743titanium, zirconium, and thorium ; 74Q titanium, zirconium, iron, andthallium ; 745 molybdenum ; 746-748 and 750 The quantitativechromatography of 18 anions on alumina-impregnated paper has been714 J.E. Strassner, Diss. Abs., 1955, 15, 1309.715 E. W. Berg and J. E. Strassner, Analyt. Chem.. 1955, 27, 1131.'16 T. Naito and N. Takahashi, Japan Analyst, 1954, 3, 125.717 F. H. Pollard, J. I?. W. McOmie, and A. J. Banister, Chem. and Ind., 1955, 1598.718 F. H. Pollard, J.F. W. McOmie, J. V. Martin, and C . J. Hardy, J., 1955, 4332.719 E. Scaffone and E. Carini, Ricerca sci., 1955, 25, 2109.720 J. Meissner, 2. anorg. Chem., 1955, 281, 293.721 W. Koberlein and H. Mair-Waldburg, 2. Lebensmitt. Untersuch., 1955, 102, 231.722 M. Lederer, Nature, 1955, 176, 462.73s S. Harasawa and I<. Takasu, J . Chem. SOC. Japan, Pure Chem. Sect., 1955, 76,724 E. M. Barilari and M. A. de Uiia de Carletto, Rev. Asoc. bioquim. argentina, 1955,725 A. Lacourt and P. Heyndryckx, Nature, 1955,176, 880.726 M. Lederer, Analyt. Chim. Ada, 1955, 13, 350.727 N. F. Kember and R. A. Wells, Analyst, 1955, 80, 735.728 A. R. Vasudeva-Murthy and V. A. Narayan, Naturwiss., 1955, 42, 439.7ee I. I. M. Elbeih. Chemist-Ana2yst. 1955, 44, 20.730 K.M. Ol'shanova and K. V. Chmutov, Zhur. analit. Khim., 1956, 11, 94.731 G. AlmAssy and I. Dezsij. Magyar Kkm. Folydirat, 1955, 61, 158.732 T. Yamada, Japan Analyst, 1954, 3, 216.733 S. Muto, J . Chem. SOC. Japan, Puve Chem. Sect., 1955, 76, 294.734 G. Almkssy and M. VigvAri, Magyar Kkm. Folydivat, 1955, 61, 109.735 J. Szonntagh, L. Faddy, and A. Jahosi, ibid., p. 312.736 C. Soye, Compt. rend., 1955, 240, 1894.737 H. T. Gordon and C. A. Hewel, Analyt. Chem., 1955, 27, 1471.738 R. J. Magee and J. B. Headridge, AnaZyst, 1955, 80, 785.73R G. StefanoviC and T. JanjiC, Bull. SOC. chim. Beograd, 1955, 20, 569.740 J. Fouarge and G. Duyckaerts, Analyt. Chim. Acta, 1956, 14, 527.741 G. Sommer, 2. analyt. Chem., 1956, 161, 336.742 E. Bertovelle and G.Fanfani, Chirnica e Industria, 1955, 37, 777.743 R. G. decarvalho and M. Lederer, Analyt. Chim. Acta, 1956, 13, 437.744 G. Alm&ssy and 2. Nagy, Acta Chim. Acad. Sci. Hung., 1955, 7, 325.745 S. Harasawa and T. Sakamoto, J . Chem. SOC. Japan, Pure Chem. Sect., 1956,746 G. AlmAssy and J. Straub, Acta Chim. Acad. Sci. Hung., 1955, 7, 253.747 M. I. Candela, E. J. Hewitt, and H. M. Stevens, Analyt. Chim. Acta, 1056, 14, 66.748 H. M. Stevens, ibid., p. 126.750 A. J. Blair and D. A. Pantony, Analyt. ChiPn. Ada, 1956, 14, 545.173.20, 173.77, 165.C . Bighi, Ann. Chim. (Italy), 1955, 45, 1087378 ANALYTICAL CHEMISTRY.described. 751 The chromatography of the halides has also been753Inorganic ElectrophoresisThe technique of zone electrophoresis on paper has been reviewed.754An investigation has been made into the separation of cations by means ofcomplex formation with polyphosphates. 755 A quantitative method hasbeen evolved for the determination of small amounts of barium and alu-minium by measurement of the width of absorption bands. 756 The techniquehas been used to concentrate inorganic ions on paper by applying currentfrom the tip of a platinum wire.757 The complete separation of niobiumand tantalum has been effected by electrophoresis on paper as oxalic acidcomplexes in a citrate buffer at pH 3.42; a current density of 4 mA (220 v)was used for 4-8 Qualitative and quantitative analysis of thealkali metals has been effected by paper electrophore~is.~~~ The simul-taneous determination of ferrous and ferric ions is possible on WhatmanNo.1 paper soaked with 0-lwsulphuric a ~ i d . ~ ~ O Wood has described thepaper electrophoresis of selenodithionates, selenotetrathionates, and telluro-tetrathionates. 761 Japanese authors have described the determination ofhalide ions by electrophoresis in dilute lactic acid at 300 v.762T. s. w.Spectroscopic Methods of AnalysisSpectroscopic methods were last reported in 1954,763 when the varioustechniques were assessed and compared in some detail. The scope ofapplication of each range of wavelength remains essentially as at that time,and it is not possible here to attempt to review details of the great activitywhich continues in all branches of the subject. Recent reviews coveringthe period from 1954 are available on X-ray method^,^^^^ 765 ultravioletspectroscopy,766 emission spectro~copy,76~ and Raman spectroscopy.768More general surveys have also been given.769-771 Infrared spectroscopy751 A. Murata, J. Chem. SOC. Japan. Pure Chem. Sect., 1955, 76, 517.752 S. Harasawa and S. Hayano, ibid., p. 789.753 L. C. Mitchell, J. Assoc. OH. Agric. Chem., 1955, 38, 532.754 L. F. J. Parker, Analyst, 1955, 80, 638.765 M. Maki, Japan Analyst, 1955, 4, 302.768 Idem, ibid., p. 413.757 G . de Vries and E. van Dalen, Analyt. Chim. Acla, 1965, 13, 554.7 5 * E. Bruninx, J . Eeckhout, and J . Gillis, ibid., 1956, 14, 74.759 0. Schier, Angew. Chem., 1956, 68, 63.F. Brom, Chem. Listy, 1955, 49, 938.7 6 1 H. VC'. Wood, Chem. and Ind., 1956, 468.7e2 E.Ohara and H. Nagai, J. Chem. SOC. Japan, Pure Chem. Sect., 1965, 76, 291.783 D. H. Wliiffen, Ann. Reports, 1954, 51, 365.764 H. A. Liebhafsky and E. H. Winslow, Analyf. Chem., 1956, 28, 583.765 B. Post and I. Fankuchen, ibid., p. 591.766 R. C. Hirt, ibid., p. 579.7e7 W. F. Meggers, ibid., p. 616.788 E. J. Rosenbaum, ibid., p. 596.769 R. F. Branch, Research, 1956, 9, 268.77O N. H. E. Ahlers, Chem. and Ind., 1956, 93.7 7 1 E. A. Braude and F. C. Nachod (editors), " Determination of Organic StructureBELCHER, SHERIDAN, STEPHEN, AND WEST. 379has also been reviewed,772 but with relatively slight emphasis on recentanalyses, and accordingly a somewhat fuller outline is given here of the useof infrared methods.Infrared Methods.-Infrared spectroscopy remains prominent amongmethods potentially able to solve outstanding analytical problems, and itsapplications continue to cover a very wide variety of substances.Theaccumulation of data makes it very desirable that fullest use should be madeof the new documentation of molecular spectroscopy, of which details werementioned in the Annual Reports for 1955.773 A number of papers alsocontain collections of numerous infrared data. Thus Pierson, Fletcher, andGantz 774 give spectrograms for 66 gases, classified to assist in the analysisof unknown mixtures.Infrared spectra have been applied to the analysis of many mixtures,including nitro toluene^,^^^ arylsilanes, 776 alkylbenzenes, 777 various nitriles, 778substituted p y r i d i n e ~ , ~ ~ ~ and other heterocyclic substances,780 polyhydricphenols,781 and mixtures of maleic and fumaric esters.782 Two closelyrelated alkaloids, atropine and scopolamine, can be separately determined, 783as can the components of mixtures of alkyd, urea-formaldehyde, andmelamine-formaldehyde resins.784 Other systems studied are condensedphosphates,785 the insecticide allethrin and associated impurities,786 anddigitonin preparations. 787 Water in fuming nitric acid has been determinedby infrared absorption.788 Several papers deal with aldehydes and theinfluence of substituents on their spectra.789* 790In wider fields, considerable work has been done on fatty acids 7919 792and their salts,793 the spectra of which appear more sensitive to structurethan those of the acids themselves.A number of steroid derivatives havebeen studied and bands determined for structures containing the reducedby Physical Methods,” Academic Books Ltd., 1955; E. A. Braude, “ Ultraviolet andVisible Light Absorption ”: R. C. Gore, “ Infrared Light Absorption ”; F. F. Cleve-land, “ Raman Spectra ”; E. B. Wilson, jun., and D. R. Lide, jun., “ MicrowaveSpectroscopy.”772 R. C. Gore, Analyt. Chem., 1956, 28, 577.773 Ann. Reports, 1955, 52, 81.774 R. H. Pierson, A. N. Fletcher, and E. St. C . Gantz, Analyt. Che,m., 1956, 28,776 F. Pristera and M . Halik, ibid., 1955, 27, 217.776 M. Margoshes and V. A. Fassel, ibid., p. 351.777 W. J. Potts, jun., ibid., p. 1027.7 7 8 E. F. Dupre, A. C. Armstrong, E.Klein, and R. T . O’Connor, ibid., p. 1878.G. L. Cook and F. M. Church, ibid., 1956, 28, 993.780 W. H. Tallent and I . J. Siewers, ibid., p . 953.781 C. C. Bard, T. J. Porro, and H. L. Rees, ibid., 1955, 27, 12.782 W. L. Walton and R. B. Hughes, ibid., 1956, 28, 1388.783 R. S. Browning, S. E. Wiberley, and F. C. Nachod, ibid., 1955, 27, 7 .784 C. D. Miller and 0. D. Shreve, ibid., 1956, 28, 200.785 D. E. C. Corbridge and E. J. Lowe, ibid., 1955, 27, 1383.i 8 6 S. I<. Freeman, ibid., p. 1268.i 8 7 0. H. Gaebler, J. Parsons, and W. T. Beher, ibid., p. 441.789 D. F. Eggers and W. E. Lingren, ibid., p. 1328.701 D. L. Guertin, S. E. Wiberley, Mr. H. Bauer, and J. Goldenson, ibid., 1956, 28,702 R. T. Holman and P. R. Edmondson, ibid., p.1533.7B3 E. Childers and G. W. Struthers, ibid., 1955, 27, 737.1218.L. White, jun., and W. J. Barrett, ibid., 1956, 28, 1538.S. Pinchas, ibid., 1955, 27, 2.1194380 ANALYTICAL CHEMISTRY.ring A.7" Spectra of six adrenocortical hormones are discussed 795 inrelation to structural features, and the bands reported for the 3-phenyl-2-thiohydantoins of 22 amino-acids 796 should prove useful in peptide studies.Other collections of data are for 17 dkyl hydro peroxide^,^^^ 10 20-iso-sapogenin acetates,7u8 and 40 2 : 4-dinitrophenylhydra~ones.7~~ An ex-tensive paper on the infrared spectra of bituminous coals and relatedmaterials shows that the technique is contributing to the diagnosis ofsuch complex structures.In the measurement of low concentrations, various means of enrichmentof the desired material are frequently used, such as fractional crystallis-a t i ~ n , ~ ~ ~ or, in particular, absorption on such substances as silica gel orcharcoal.The former absorbant was used to enrich ozone in the measure-ment of its atmospheric concentration,m1 ultraviolet spectroscopy beingused in this example. Traces of alkyl benzenesulphonates in water havebeen determined specifically for the first time, by means of infrared spectro-scopy following enrichment by absorption on charcoal. m2In other cases, emphasis is on continuous monitoring of material withoutany pretreatment. For such purposes, the sensitivity of non-dispersiveinfrared analysers has been made very great, and applied, for example, tocontinuous monitoring of organic chemicals in the atmosphere,803* atconcentrations from 0-1 to 10 parts per million.Technical means of im-proving the selectivity and sensitivity of such analysers have been de-scribed.s05*Spectroscopic technique in the infrared has been the subject of a numberof papers. Kaye has reviewed methods for the near-infrared region.807A device for the automatic measurement of integrated absorbance has beendescribed.8O8 Work has appeared on spectroscopic standards for rneasure-ments on solids, for which powdered calcium carbonate is suggested,809 andfor gaseous spectroscopy.810 Several papers deal with the potassium bromidedisc technique,811 and its theoretical background.*l2. 813 Technique forquantitative estimations in aqueous solution at 6-5-10 p has been de-scribed. 814794 H. Rosenkrantz and P. Skogstrom, Analyt. Chem., 1956, 28, 31.795 A. L. Hayden, ibid., 1955, 27, 1486.79G L. K. Ramachandran, A. Epp, and W. B. McConnell, ibid., p. 1734.7 9 7 H. R. Williamsand H. S. Mosher, ibid., p. 617.' ~ 3 1 3 C. R. Eddy, M.-A. Barnes, and C. S. Fenske, ibid., p. 1067.799 L. A. Jones, J. C . Holmes, and R. B. Seligman, ibid., 1956, 28. 191.800 R. A. Friedel and J. A. Queiser, ibid., p. 22.802 E. M. Salee et al., ibid., p. 1822.SO3 F. E. Littman and J. Q. Denton, ibid., p. 946.SO4 V. C. Shore and &!I. Katz, ibid., p. 1399.S O 5 W. J. Baker, ibid., p. 1391.A. W. Wotnng, R. F. Wall, and T. L. Zinn, ibid., p. 1396.ao7 W. Kaye, Spectrochim. Acta, 1955, 7, 181.V. 2. Williams, V. J. Coates, and F. Gaarde, Analyt. Chem., 1955, 27, 2017.*OD L. E. Kuentzel, ibid., p. 301.F. Pristera and A. Castelli, ibid., p. 457.811 J. J. Kirkland, ibid., p. 1537.G. Duyckaerts, Spectrochim. A d a , 1955, 7, 25.J . Bonhomme, ibid., p. 32.W. J. Potts, jun., and N. Wright, Amz@vt. Chem., 1966, 28, 1265.F. E. Littman and C. W. Marynowski, ibid., p. 819BELCHER, SHERIDAN, STEPHEN, AND WEST. 381Microwave Methods.-The potentialities of microwave spectroscopy 7719 816€or chemical and isotopic andysis were briefly summarised in the AnnualReports for 1954. Though few applications have been made, the past twoyears have seen increased activity in microwave spectroscopy in Europe,and the specialised equipment, such as klystron oscillators, crystal detectors,and waveguide components, has now become more easily available commer-c i d y on this side of the Atlantic. Townes and Schawlow consider analyticalapplications in some detail in their standard work on microwave spectro-scopy.816 To illustrate the advantages of the immense resolving power, theypoint out that, if each of a hundred substances in a mixture has 20 absorptionlines in a 10,000 Mc./sec. interval, then the chance that more than a third ofthe lines of any one substance will be overlapped by others is less than onein a million. This feature is continually utilised by microwave spectro-scopists in the detection of impurities and isotopically substituted molecules.Microwave spectroscopic analysis depends on the availability of extensivetables of observed spectra, and the compilation now being completed bythe National Bureau of Standards will be much larger than any previouslyavailable.Detailed publications have appeared on the theory and technique ofmeasurement of relative and absolute intensities of microwave absorp-tions,sl7* 8181 819 a matter clearly fundamental to all quantitative studies.With further work on specific cases for which the method is suitable, theattainable precision should increase towards that realised in the simplerproblem of isotopic analysis.Since the technique is bound to be more specialised than, for example,infrared spectroscopy, the expense of wide frequency coverage may not benecessary. Townes and Schawlow 816 find that about 60% of the sub-stances for which spectra are known possess one or more lines in any intervalof 5000 Mc./sec., a range which might be covered by one good klystronoscillator. Of these 60%, about half would have lines strong enough to bedetected in a very simple spectrometer. For specific problems, such as theisotopic analysis of nitrogen or carbon, the narrow frequency range requiredcould be obtained cheaply as harmonics of long-lived 3 em. oscillators. Ithas also recently become clear that the expense of commercial crystaldiodes can be avoided, and other advantages gained, by use of adjustablesilicon-tungsten contacts as detectors and harmonic generators.Nuclear Magnetic-resonance Methods.-There is now a wide realisation ofthe potentialities of nuclear magnetic-resonance spectroscopy 7639 7709 815,821for the solution of special analytical problems. The technique derives itspower from the particular causes of the absorptions and their fine structures,815 B. P. Dailey in " Physical Methods of Organic Chemistry. Vol. I11 " (Ed.A. Weissberger), Interscience Publishers, Inc., New York, 1954, p. 2321.810 C. H. Townes and A. L. Schawlow, '' Microwave Spectroscopy," McGraw-HillBook Co. Inc., New York, 1955, Chapter 18.81' D. H. Baird and G. R. Bird, Rev. Sci. Instr., 1954, 25, 319.B18 G. R. Bird, ibid., p. 324.819 H. R. Johnson and M. W. P. Strandberg, J . Chem. Phys., 1952, 20, 687.820 A. L. Southern, H. W. Morgan, G. W. Keilholtz, and W. V. Smith, Analyt. Chem.,s21 J. N. Shoolery, ibid., 1954, 26, 1400.1951, 23, 1000382 ANALYTICAL CHEMISTRY.which are often strikingly effective in revealing structural features andrelationships between groups. It also has fundamentally simple relation-ships between intensities and concentrations. High-resolution spectra dueto proton and fluorine resonances are being rapidly accumulated for a widevariety of materials, and chemical shifts in the spectra of other nuclei arebeing reported. Some of these, for example shifts in the phosphorus,822nitrogen,s23 and oxygen-17 824 resonances, appear to promise ultimatelysome revolutionary changes in analysis and process control. For instance,separate oxygen-17 resonances,824 observed with the small natural concen-tration of this isotope, are resolvable for such substances as water, hydrogenperoxide, nitrates, nitrites, and other important chemicals. A similarresolution of nitrogen resonances in important groupings is whilethe phosphorus resonances have already been discussed specifically foranalytical purposes,822 and relative concentrations of different phosphorus-containing anions measured to within 2-10%. A documentation systemfor high resolution nuclear magnetic-resonance spectra is at present beingdevised by the American Petroleum Institute.825J. S.K. BELCHER.J . SHERIDAN.W. I. STEPHEN.T. s. WEST.822 C. F. Callis, J . R. Van Waser, and J. N. Shoolery, Analyt. Chem., 1956, 28, 269.828 B. E. Holder and M. P. Klein, J. Chem. Phys., 1955, 23, 1956.a24 H. E. Weaver, B. M. Tolbert, and R. C. LaForce, ibid., p. 1956.S 2 j American Petroleum Institute Research Project 44