V O L U M E 2 3 , NO. 1, J A N U A R Y 1 9 5 1 ( X 2 ) Stevens, R. E., and Lakin, €1. W., U. S. Geol. Survey, Circ. 63 (1949). Chromograph, new analytical tool for laboratory
and field use.
;263) Stock, J. T., and Fill, 11. 8.. Analyst, 74, 319-20 (1949). Rotary stirring devices for microtitration. 264) Stock, J. T., and Fill, 11.2.A., Melallurgia, 40, 180-1 (1949).
Miscellaneous microchemical devices. Adjustable support for light apparatus. ,265) Ibid., pp. 230,232. Control of swings in semimicro weighing. i266) Ibid., 41, 170 (1950). Improvised microburet. ’ 267) Ibid., pp. 23940. Rotary stirrers for microtitration. ’ 2rj8) I b i d . , pp. 29W-1. Holding and clamping devices. ‘ 2 i ; S ) Stock, 3.T., and Heath, P.. IhLd., 41, 171 (1950). Hydrogen
sulfide supply system. 2 7 0 ) Stock, J. T., Heath, P.. and Marshment, il’., Ibid., 41, 345--6
(1950). Modification of Lidstone-Wilson micro hydrogen sulfide generator. 271) Stover, C. X . , Jr.. I’aitritlge, W. S., and Garrison, JV. A I . . ASAI.. C H E x . , 21, ioi:i (1949). Simplified gas microanalyzer. , 2 7 2 ) Suto, ToshiB, Y c l e n c ~ . 20, 182-3 (1950). Microcheniic%al reactions on filter paper applied to sulfide minerals. , 2 7 3 ) Tanaka, hlinoru, hshizawa, Takashi, and Shibata. SIuraji, Chem. Researches, 5 , Inorg. and Anal. Cheni., 85-52 (1949). Chromatography for inorganic compounds. 27.4) Tananaev, N. A., Ruksha, S . P., and Verkhorubo\-a, A. X., Zhur. Anal. Khirn., 3, 271-5 (1948). Drop method for detecting iridium, palladium, platinum, thallium, and copper. ( 2 7 5 ) Tarasevirh, N. I., 1-estnik M o s k o a . Univ., 3, No. 10, 161-8 (1948). Rapid gravimetric determination of silver. Analytical properties of bromoaai~nidobenzene. ( 2 7 K ) Tarasevich, N. I., Zhur. Anal. Khim., 4, 108-13 (1949). Macro and micromethod for determination of copper and mercury. 1277) Thomas, 3. W.,Shinn, I,. h.,Kiseman, H. G., and Moore, L. A., AXAI,.CHEX.,22, 726-7 (1950). Mcrodeterminntion of iodine, improvement in reflux distillation apparatus and technique. 5 ’ 8 ) Thrun, IT. E., ANAL. CHEX. 22, 918-20 (1950). Elapid methods for determining fluoride in waters. ’279) Tribalat, Suzanne. Anal. Chim. L4ctn, 3, 113-25 (1949). Extraction and determination of traces of rhenium, especially in molybdenites. ( 2 8 0 ) Trtilek, Josef, C h n . Listy, 38, 128-34 (1944). Deterniination of traccs of iodine. 231) Truffert, Louis, A n n . fals. et f m u d e s , 41,368-9 (1948). Microchemical identification of metals. ~ , 9 8 2 )Uheda, F. B., and Gonzaler, E. L., Anales fis. 1/ qubrn., 41, 249-56 (1945). Formation of insoluble compounds of
59 4,4’-diamino-3,3’-dimethoxybiphenyl (0-dianisidine) with tungstates in aqueous solutions and applications to determination of tungsten. (283) Ihid., pp. 267-62 (1946). Formation of insoluble compounds of 4,4’-diamino-3,3’-dimethoxybiphenyl (0-dianisidine) with vanadates in aqueous solutions and their analytical applications. (284) Underwood, A. L., and Seuman, W, F., hs.4~.CHEX., 21, 1348-52 (1949). Color reaction of beryllium with alkannin and naphthazarin. Spectrophotometric studies. (285) Toter, R. C., and Banks, C. V., Ibid., 21, 1320-3 (1949). Xater-soluble 1,2-dioxinies as analytical reagents. (286) JVenger, P. E., RIonnier, D.. and Pamm, I., Hela. Chiur. ; I d a , 32, 1865-9 (1949). Semiquantitative determination of sulfur anions (sulfhydric, sulfurous, sulfuric, thiosulfuric, and persulfuric). ( 2 8 7 ) \\-est, P. W.,As.41.. CHEX.. 21, 79-89 (1949). horganir niicrochemistry. (288) Ihid., pp. 1342-4. Organic reagents i n inorganic analysis. Sources of error and interferences. (289) \Vest,, P. W.,Brazil, Ministerio agr., Dept. nncl. produ$do mineral, lab. producdo mineral, Bol. So. 27, 29-40 (1947). Reactions of parafuchsin acid with gold chloride and palladium chloride. c290) Tl-est, P. IT., Burkhalter, T. S., and Broussard, Ideo, ASAI.. CHEX.,22, 469-71 (1950). High-frequency oscillator utilizing heterodyne principle to measure frequency changes induced by diverse chemical systems. (291) \Vest, P. W.,Folse, Patricia, and Montgomery, Dean, Ibid., 22, 667-70 (1960). Application of flame spectrophotometry to water analysis, determination of sodium, potassium, and calcium. (292) JVilmott, P. L., and Raymond. F. J . . Analyst, 75,24-7 (1950). Determination of small quantities of copper in lead and lead alloys. (293) \\.ilson, A. E., and Kander. I . W,, AXIL. CHEM.,22, 195-6 (1950). Elimination of intcrference by copper in Titan yellow method for niagnrsinm. (994) JVinslow, E. €I., and Liebhafsky, 1%. A . , Ibid., 21, 1338-42 (1949). Spectrophotometric study of spot tests. (295) Zaichikova, L. B., Zavodskaya Lab., 15, 1025-7 (1949). Tse of thiourea in colorimetric determination of molybdenum. (296) Zhdanova, K.V.,Slyusareva, R. L., and Tesner, P. A,, Ibid., 15, 647-9 (1949). 3Ieasnremerit of moisture content of a gas. (297) Zinimermann, \Vilhelni, dlikrnciwnie wr. Mikrochim. Acta, 35, 80-2 (1950). Microanalytical determination of sulfur in organic and inorganic snhstances. R E C E I V ESovernber D 15, 1950.
Inorganic Gravimetric Analysis F. E. BEAJIISH
AND
W. A. E. JZCBRYDE, Crnic.ersity of Toronto,
T
HE present review rcveals ,in increased intere>t in proce-
dures designed t o improve the physical characteristics of the precipitate. Following the previous practice of the authors, this review covers publications whose abstracts were iecorded during the period June 1949 to June 1950. GEYERA L PROCEDURES
Preparation of Samples and Precipitates. Chapman, h r v i n , m d Tyree (26) investigated losses incident to evaporations in the presence of perchloric and hydrofluoric acids. Of 34 elements investigated, appreciable lossr~s occurred nith horon, silicon, germanium, arsenic, antimony, chromium, -elcnium, manganese, and rhenium. A method of preparing aaniples of iron and mangane,se ores and of unslnkrd lime n-aq liescribed by Khripach (88). Benedetti-Pichler (10, 11) recorded efficient procedures for the calibration of weights and included suggestions for safeguarding against errors. The advantages of internal calibration were also discussed. Eaton (49)modified Richard’s method of standardization of weights. Provision was made for cases where the rider differed significantly from its nominal value.
Toronto,
Cunadu
I h v n l (40)found that, it11 asbestos iilteiing nic~tliuinlost neiglit, Ivhrn licnted above 283” C. Dupuis and 1)uval (38) csaminmt the temperatures of stability of precipitates used for the detwniination of anions, ineluding phosphates, arsenates, si1icate.s.. :tnd halides. Suitable temperatures m r e given for heating about seventy compounds encountered in gravimetric mork (S9). For drying prrcipitates, etc., >LIonnirr and Besso (104) recommended the use of infrtrred rays, thus avoiding decomposition by heat. Kuenetsov (99)dcwrihwl thr preparation of two organic reagents which could be used for cstimating the efficiency of ~vashing precipitates. Colored salts or solutions were ohtained by a wide range of cat,ions including uranyl ion. Methods of Selective Separations and General Gravimetric Reagents. For the annlysis of alloys containing nickcl, copprr, sulfur, phosphorus, and arsenic, Lur’e and Filippova (98) used phenol or resorcinol sulfonated resins to remove nickcl a t pH f i :md copper a t p H 5.5. Lassieur (96) discussed the use of cupferron in analytical chemistry. Shome (157) preferred S-henzoylphenylhydroxyl:imine to cupferron for the gravinwtric determination of copper,
60
ANALYTICAL CHEMISTRY
wards and h o c k ( d $ ) described two routine gravimetric mrtliods iron, alunlinuin, :tiid titanium. The former w:is found to be for the determination in boiler scales of iron, aluminum, calcium, more stable toward heat, light, and air; the precipitates became and magnesium without reim)val of phosphate. Jean (83) granular 011 heating and were not, cont,aminated by the prerecommended methods for the determination of copper, mercury, cipitant. The optimum pH values for the preeipit,ation of copper, and arsenic in antifouling marine paints containing considerable iron, and aluminuni were, respectively, 3.6 to 6.0, 3 to 5.5, iron. Baskerville ( 7 ) developed a procedure for the analysis of and 3.6 to 6.4. \’icndland, Smith, and Muraca (160) reported copper-base alloys containing small amounts of beryllium. The t h a t 2-dibeiizofur.ansulfoiiic acid appeared to be a general metalion precipitant even for thr alkali metal ions. alloys contained nickel, cobalt, silicon, chromium, silver, zirHovorka and Holzl)cvh~r(78)examined the reactions of cat’ions conium, phosphorus, and only negligible amounts of iron. The methods used for these constituents were not new. A method of Jvith the p-seinicarbazoiit: of isatiii and its derivatives. In 90% rlthyl alcohol, orang(’ or yrllow precipitates were produced with determining sand in t,he waste obtained in grinding brass or i ) i . o r i z i ~ silver, nirrcury(1) and nitwury(II), and bismuth, In an alkaline was recorded by Goldberg (51),who also published a procedure for the estimation of silver and copper in silver fielder (58). solution of 35% ethyl alcohol the precipitation react,ions were Ascorbic acid was used to precipitate the silver, which was cletrrextended to include knd, thiillium, copper, cadmium, nickel, cobalt, manganesc~, ziiic, iron, calcium, barium, and strontium. mined subsequently by ignition to the metal. Most of thc’w cutions MY’I’C also precipitated by tlltx 6-semiKeller (87) devised a simple procedure for determining the c.:irhwzonesof .Y-nic~thylisatin:rnd S-benzylisatin. Thew authors proportion of calcium sulfate dihydrate in technical semihydrate. igrttcvi the reactions of cations with thc, 3-thioThe method involvcd convtwion of the mixture to anhydrous of isatin aiid its derivatives. Hovorka m d Divis ~(,iiiic,:ii,l)azoiies calcium sulfate a t 125” C . , which upon exposure to aqueous (T6) discussed the character of the metal salts of 2-is:ttoxime. vapors from saturat,etl sodium chloride solution formed the wmiI n an :wid mcdiuni iiic~rcury(Il),copper, and ur:inyl salts were hydrate. Magneli (100) recorded a procedure for the analysis of t’ungsten bronzes, which involved the gravimetric determination precipitated; in sodium acetate solution lead, silvc,r, zinc, and of tungsten as rncicury(1) tungstate. A rapid method foi, thr. bismuth salts were formed; in an alkaline mediuni barium, thodetermination of iron oxide in sinter cake based upon the itirium, cadmium, lead, nickel, and cohalt, salts n-cw piwipitatrd. Voter and Banks (257) found that, of the 1,2-dioximes excreaw of m i g h t of iron(1I) oxide upon calcining was reeortkl 1)y amined, only 1,2-cyciohesanedionedioxime and 1,2-c~ycloliel~t:iiie- Plotkin, Usatrnko, iind Bulakhova (129); 2FeO.SiOz TWS unaltered by 2-niinuk trsposures to 1000” to 1100”in air or os!-grn. tiionedioxime were sufficiently water-soluble to rep1:~cetliniethylTo determine zinc oxide in zinc powder, Balis, Bronk, a n d glyoxinie in annlysifi. Directions were included fol, t l v clcterLiebhafsky (6) volatilized the zinc in a vacuum a t 450”. Tiits nlination of nickt.1 in steel. T h r analytical uses of tlithiocarbsample, in a copper boat, \vas \vrapped in annealed copp(~1’f o i l . amidohydrazine were discussed by Gupta and Cliakixbartty Mayants (102) recordcd t\vo procedures for the deterniin:ition (65). While inso1ut)le salts were formed in thtl prewnce of both of zinc silicate in thc presence of zinc oxide and quartz. The copper(I1) and copper(I), the latter was better suitrd for anasimpler of these involved the selective dissolving of zinc silicatcx lytical work. Pilipenko (118) recorded a “solubility wries” in 20y0 sulfuric acid. l’i(Ltcrs (11:) reviewed procedures for the of various metal ethyl santh:itrs. The solubility proc1uc.t of thc analysis of pyrites. s silver salt ~ : t detc~niincd. Theories of Precipitation, New Aids, etc. Klyachko aiid Spakowski arid Freiser (142) stated that isoquinoline ivith thioKondratyuk (89)diecu d the “dependence of the precipitntioli cyanate ion produced precipitates with bivalent catioiis which reaction and the nature of the precipitate upon the order in n-hitali c*ouldbe d r i d ;rnd weighed. The reagent could be usrd for thr solutions react.” Thtly concludcd t h a t lyophobic precipit:tirs separation and determination of copper and zinc in hr:w and \vas like barium sulfate iit nqutxous medium were more crystalline wher I :tho applica1)le to the determination of c o p p a in Grrni:in silver, the precipitant WIS :rcttlcd gradually, b u t lyophilic precipitates bearing metal, and sulfide ores. The origin of positive errors like hydrated ferric oxide should be formed rapidly froni roiiwhen tannin was used as a precipitating agent wns traced by rentrated solution, Chovnyk and Kuz’mina (26) studied t lie Holness and 1Iattock (75) to the presence of heavy metal hicompositioiis of salts formed by potassium cyanoferrate(II1) purities in the tannin itself. .\ method of purific:ition wits inand solutions of nickvl, zinr, and copper. A new variation of :I cluded. Yoe (166) reviewed recently reported colorimetric and volunietric-gravimc:ti~icmethod of analysis examined by Porfir’w, gravimetric organic reagents. Lavrova, and Evdokinior (171 ) involved weighing the solution Analytical Methods for Specific Materials. Elving a r i d Chao before and after titration :ind thus determining the weight i , f ( . $ 5 published ) a procedure for the determination of alkali metals titrant. Kodama (-90) comp:trccl methods of gravinwtry, voluin silicates which merits attention. The method was c1:iinicd to nietry. and colorimetry in inorg:iriic analysis. be much simpler in manipulative detail ‘than that of J. T,axz-rence Smith. The sainplc was treated with sulfuric and hydrofluoric LIGHT ALLOY ELEMENTS arids, and the residue IV:LS oxidized by ignition to render the triLithium and Magnesium. Bonnier ( 1 4 ) separated lithium valent oxides n.ater-insoluble. RIagnesium and calcium were from calcium and aluminum b y evaporation with sulfuric : i d precipitated in an acetate medium by ethyl oxalate, a procedure and addition of ethyl alcohol. Following removal of aluminuni, previously described by Gordon and Caley (60). Sodium and magnesium oxide vas precipitated by barium hydroxidv. Lithpotassium yere rccovercld as sulfates. Vecchi (164) recordcd a ium was determined :is the sulfate or triple acetate. scheme for the analysis of silicates which incorporatcd standard Chugunova and Iranova (27, 80) determined magnesiu~iioside methods of determination for silicon, aluminum, iron, titanium, in potrdered magiicsium hy srJlrctive extraction with a solution cdrium, magnesium, and alkali metals. A procedure for the: of chroniium(T’1) oxide. This procedure appears to h a w I)wn deterininntion in tin alloys of lead, tin, iron, antimoiiy, anti patented by the authors (80). (Bopper as described hy Buogo and Rndogna ( 8 1 ) . Aluminum and Beryllium. The system aluminum fluorideKallrnan (84)extended his researches on the analytiwl :ipplicasodium fluoride-watrr K:LS exnmi~iedby Tananaev and Lel’chuk tion of butanol-hydrogen chloride to the analysis o f harytes. (144). I t TVRS shon-n that of the two possible double salts, Following the removal of barium choridr hy a 3 to 1 mixture 3SaF..\lF3 and 1lXaF.4;I1F3, obtained during precipitation, of 11.0 S hydrochloi,ic acid solution and hutanol, strontium the latter predominated at ion- concentrations of sodium fluoride, chloride was isolated by 20% hydrogen chloride in butmol and was the product of hydrolysis when solutions of the former from a solution containing the perchloratcs of strontium, cal\rere diluted. Iluniiiiuni could lie precipitatrd as the sccond of cium, magnesium, iron, and aluminum. Final purification in these compounds a i i ( 1 wp:i~,:Ltc~d from most other ions. Dupuis the form of strontium sulfate or carlmnatc \\-;isc.fYcctcd. M-
V O L U M E 2 3 , N O . 1, J A N U A R Y 1 9 5 1 :uid 1)uv:tl (32) reported that, l l ~ a ~ . 4 . ~could 1 F ~be heated to coiistaiit weight only between 66" ttnd 82" C. These authors tlrtc~rniiiiedsuitable ignition tempcraturcs for various aluminum piwipit:ites. The results of the examination of hydrated aluminun1 ositle precipitation mere of special interest. Treatment of a solution of aluminum nitrate a t 15" with a slox current of air c l w g r d with ammonia was recomniendctl. Precipitation began :it p1I 5 . 5 and WAS completed a t 7.8; const:tnt weight x-as obtnitietl upon ignition at 475' and 1000". K i t h other methods of precipitating the hydroxide, higher igiiition temperatures ware required. There were also inclutlecl diita dealing with sxfe ignition temperatures for aluminum chloride, aluminum orthophosphate, arid the aluminum compounds of 8-quinolinol (S-h~th.osvquinoiiii(~),cupferron, :md 5,7-dibromo-8-hydroxyquirioliiic. Because of the narrow range of permissible ignition t!xiiiperatures, the litst reagent was not reconiniended. 0sl)orn and Jewal)ury (111 ) used ammonium benzoate to wliar:ite d u m i n u m from beryllium. .it pII 3.5 to 4.0 aluminum \v:ts quantitativtdy precipitated, Lyhile initial precipitation of Ilium occurred :tt pH 6.5, With high ratios of alumina to llium oxide nluininum could I F dctrrmined with an accuracy of ahout 2%, dtliough in such cases adsorption resulted in serious of klryllium. Double precipitations were required in all c:i';.w. 13owitz and Young (18) prtcipit:it,ed beryllium by S-quinolinol in a Iluffrred acetatc. solution. .VAT UK A LLY RADIOACTI V F: E L E If ENTS
Thorium and Uranium. Ilodden (I?,?) discussed extensively chcniical and r:itliochemiral nicthotis uscd for the determinai ion of utwiiuni :ind thorium. T h r c,hcmical methods n-ere considered more acvutxte. For macro iiniounth of uranium, following the separation of other eletiicnts, gr:iviiiictric methods could IJCitsid. A list of precipitation romp on it ion^ \viis included, all of tvliicli w r e convc.rt(.d to the \wighirig form U i 0 8 . The author stated: "Titration procedures ;~ri:goii(~i,:illyconceded to be the i i i i i a t s:itisfactory otics for thc c,;.tini:itioii of macro quantities of ~ i i ~ : i i i i i i i i i . 1lic:rotitrations m:r>. I i i ~p c h r m r d satisfactorily, liiit ciilot~imctrie01' other optio:il mothods are grnerally prefer:ihk for the estimition of am:ill :tinoutits of uranium." For thorium, p x i p i t n t i o n methods \ v , w > nsu:illy cniployed. The :iuthor irivluded :t uwful discussioti of c.lirniic:il mrthotls of separat ion and precipitation. Dupuia and I)uv:tl (37) dvti*riiiiii(Silt h r optimum conditions for tho tlt,ying or c3:ilcination of v:ii~iou.; t,liorium precipitates. These included the ehacate, iotlatr, salt of 5-quinolinesulfonic :icitl, normal hydro de, pyropho~ph:itc, m-riitrobenzoate, picroIonate, wlcnitv, tli sulfate, osltl:itc,, and fumarate. The last four wrre consitlrwd unsatief:ictory Iiwcipitanta. The separatioil of thorium fivm the rare c3:irths of monazite sand by tetracliloi~~)phtlialic ncid \vas discu. 1 hy (;ordon, Vanseloi\-, and iViilard (61). Diwctions i v c w givrn for t,he isolat,ion of rare r:ti.ths i t n d thorium from a 1-gr:tm sauiiplc of finely ground mon: i z i t r sitntl by trc*:tt,iiirnt with mcth~-lox:tI:ttr. The subsequent si,p:iration of thorium Ily tetrnohlortij~hthalic acid mas accomplished :it p l I 1.0 to 1.1. Repi,wipitution was required and the wighing form wis thorium diosidf,. For thc preliminary separat ion of thorium :bszzo (2) added sulfur dioxide and oxalic acid to tlie filtrate from a sulfuric :iritl treat'ment of monazite sand. 'rh? o w h t e s w ( w osidizrd and dissolved, and then reprecipit:itcztl. Three kiiown methods for the subsequent determination o f tliotiutii were recvmmended. I Ii,vot.k:t and IIolzhecher ( 7 7 ) i~ecordedthe fifth communicat iott of Ilovorka's wsearches on t,lie :tpplii.tition of isatin &oxime t o tliv wparatioti :tnd determiiiation of uranium. Interference f i , i i i i i rilver, lead, :tnd copper \\-as prevented by addition of sotlium t,hiosulfatn>, while excess chloride ion prevented the Iiriv.il)it;ition of mcrcury(I1). The mcthod was applicable in t I I ( ~ Iii'e*nce of wrium(1TT) n.nd th:illium(I), In an earlier Ilcc
61 paprr the, :iuthors stated that precipitatiou could 1x2 made over the range of I to 240 mg. of uranium. The uranium complex was ignited t,o U30a. The optimum ignition temperature range (408" to 946') of this complex, according to Duval (41), was greater than for any twelve other uranium precipitates requiring ignition to LT308. Some eighteen methods were examined by Duval, and reference \vas again made to the tlyo new Tveighing forms, oxalate :Lid 8-hydroxyquinolatc. Norette (106') dealt with tlie separation of uranium from phosphoric acid, which involved treatment of t,he solution with calcium hydroxide and subsequently nith ammonium carhonatc. The filtrate was treated with aqueous ammonia to rrmove uranium. (ilark (28) and Bonnier (15) recorded methods for the rcrovrry of uranium from precipitates of the triple :I( ALK.iLI AND ALKALINE EARTH ELE3ZENTS
Sodium and Potassium. Wendland and Smith (1i;s) statcd that dibcnzofurnnnionosulfonic acid formed salts with sodium and potassium n-hich were stable a t 100' and sufficiently insoluble to be used for gravimetric determinations. The alkaline earth elements and certain others interfered, but the ammonium salt IVW relatively soluble. Peltier (114) found that the solubility of the sodium salt of 1,3-dihydroxybenxcne-4,6-disulfonicacid ivas too great to permit its use for gravimetric determinatioiis. HoFYever, in chloride solution the sodium compound as rclatively insoluble as compared to the other mcmhers of Column I A l , magnesium and ammonium. Borgioli and Iacozzilli ( 16) precipitated potassium in cold solution by sodium 2-chloro-3-nitrotoluene-5-sulfonate and dried the comples a t 120". Salts of barium and ammonia interfered. Sodium was precipitated b,y nickel uranyl acetate or the corresponding zinc salt. Bwtiaus ( I S ) published a procedure for the determination of sodium in aluminum and light alloys. Sodium was determined as the sulfate. In the separation of alkali metals from silicates Tokarski (150) evspnmted the solution containing t,he rhloritles of sodium, potassium, and calcium to a small volunie :tnd added ethyl alcohol to precipitate sodium aiid pot.:iwsirim chloride. The applicability of the pyroantimoiittte mr,thod for th(x precipitxtioti o f sotiiuni iii the prc'sence of potassium was invcxstig:ttcd by Viuogradov and Duiidur (f56). Satisfactory results \ w i ~ 'ol,taitied \vhen the ratio of sodium to potasaiurn d i t 1 riot rst,cwl 1. The separation of podium from potassium hy organic ion es(~huigers v a s invcstigntcd by liayae (86). T h r rmin used was ALmk)erlite IR-100 niid thc eluant was perchloric :irid. Dripuis (30) publishxl a ievic\v of paperP of thr pmt t1cc:itlr tlmprratureP of ignition W ~ I Y not recorded. For thca subsequent dptermination of iiiagnc,sium, ammonium oxalate could be removed by bromine but not by nitric acid. 1,ockem:tnn ( 9 7 ) statcd that ignition of calcium oxalate nbovc 600' re-
ANALYTICAL CHEMISTRY
62 sulted in the formation of thcl basic calcium carbonate. Ca0.CaCOd, which was stable a t 700'. Heating above 800' caused further loss of carbon dioxide. Calcium carbonate was stable up to 600'. Duval (42) recorded t h a t calcium carbonat(>could be heated to 666' without decomposition. These latter statements were not supported by the investigations of Willard and Boldyreff (161) a s reported in 1930. These authors recorded significant losses of weight when calcium carbonate was heated to 550'. Furthermore, Duval's investigations of the stable weighing forms resulting from ignition in air of calcium oxalate do not indicate the existence of a stable basic carbonate ab RURgested by Lockemann. The discrepancies in the literature dealing with the ultimate limits of safe ignition temperatures are not unexpected. The analyst would do wrll 1 7 avoid applying the limits of the "Eafe heating ranges" of prwipitates as recorded by various authors. In the case of the carhoi.atrs particularly, ignition is generally accomplished under varying partial pressures of carbon dioxide. With oxides or hydrates the limits of safe ignition are also somewhat ragged, depending upon various factors such as the partial pressure of the oxygen or water vapor in the adjacent atmosphere and the character of the heat source. The precipitation of calcium by "hexyl reagents" was drscribed by Fukuei (52). ThBry (149) determined calcium as phosphate in aluminum and its alloys by treatment of thr caustic solution with sodium cyanide to form complexes n-ith copper, nickel, arid zinc and with hydrogen peroxide for lead. The precipitate of calciu~ii phosphate was analyzed for the associated impurities manganese, iron, and aluminum. Calcium was precipitated finally as the oxalate. Ustrenko and Datsenko (163) used the ion exchange resin, Wolfatite R, to separate cal( k i n and magnesium from solutions of iron ores. The adsorption of impurities was prevented by complexing with tartaric acid, and calcium and magnesium were eluted by hydrochloric wid. Gaspar y Arnal and Matesctnz Rojo (66) found t h a t the determination of calcium, strontium, and barium as carbonates nr sulfites in 60% ethyl alcohol followed by conversion to sulfate \$as prrfwable to the direct precipitation by sulfate. Dupuis :md Duval (36) reviewed publications of the period 1939 to 1949, dtdirig with the determination of the alkaline w r t h clnmrn ts. STEELFORMING ELEMENTS
Titanium and Zirconium. Guerreiro (63) isolated titoilium from iron and aluminum in solutions of iron ores by complexing the oxidized titanium R ith hydrogen peroxide in an ammoniacal medium, precipitating the titanium a.; the hydrated oxid(., and drtermining it as the oxide. Holness and Kear (72) recorded a method for the determination of zirconium, titanium, etc., in minerals and refractories. The sample was fused with sodium bonate, then an extraction was made with sulfuric acid, and s a was volatilized from the residue, which was then fused with potassium hydrogrii sulfate. Thc. metals of the hydrogen sulfidr. group were removed from th(x combined solutions and the filtrate was treated with aqueouP ammonia and ammonium chloride. The resulting precipitate, after purification, was dissolved by hydrochloric acid, and ammonium chloride and tannin were added to remove zirconium along with some titanium. From the neutralized filtrate thv remaining titanium was precipitated by tannin. After furthei addition of aqueous ammonia, iron and aluminum were rtlmoved. ITithn (68) examined the mandelic acid procedure, previouslj developed by Kunimins (92), for the determination of 1 to 15 nig. of zirconium. The method was a8 accurate and faster than the phosphate method. In the presence of aluminum, iron, and titanium the mandelic acid method was superior to the phosphatil method. Succrssful separations Fere made in the prescnw of magnesium, mercury, nickel, uranium, zinc, cobalt, and nilin-
ganese, :rlthougli the last twn contaminitted the precipitate elightl? Iiafiiium was also quantitatively precipitated. ( k ~ p t . 1and Klingenberg (109) found that certain derivatives of m:tridelic acid muld be used to advantage, p-Chloromandelir anti p-tromomandelic acids produoed inor2 voluminous precipitate- of zirronium. The attempt* to u5e this advantage in a dire( t \wighing procedure weie eucvc-sful only in the caw of pure ZLI ('oniuni solutions. Thei(. n u s no deciease of selectivitv of precipit:ttion as compared to mandelic arid. The results obtained on zirconium-bearing materials compared f a v o r a b l ~ Rith those obtained by the cupferron method. Gump and Bherwood (64) made a study of the factors involved in the prccipitation of zirconium and hafnium arsenates by the formatinu of arsenate ion within the solution. The precipitates formed were of better quality than the ordinary phosphate, hydroxide, or arsenate. Vanadium and Niobium. Fidler (4)stated that in a u-eabl\ acid solution vanadate could be precipitated quantitatively with dicvanodiamidene. Alkali chlorides or nitrates did not interferc; phoqphatcs or arsenates gave low results; molybdates or tungstattas gnvt. high results. SvrokomskiI and Klimenko (143) dealt Rith the determination of niobium in the presence of titanium. The sample was t r e a k d to volatilize silica and the residue was fused with potassiurii pyosulfate, then extracted with sulfuric acid solution in the presence of hydrogen peroxide. Titanium was reduced by zinc amalgam, ammonium acetate was added, and niobium was precipitated a t pH 1.5. The titanium content of the precipitate, R ' ~ Pdetermined colorimetrically. -4 patent covering a procedure for determining niobium in iron and steel was recorded hv Hilliard (71). The sample was dissolved in a mixture of hydrochloric and nitric acids, silicon was removed by hvdrnfluorir acid, and the solution was evaporated in the presence of pcrchloric acid. Niobium pentoxide was precipitated from the aquoous solution by addition of concentrated sulfurous arid in hvdrochloric acid. Waterkanip (168) described six procedures for detrrmining niobium and tantalum. The properties of Ralts of these metals which are uwful in analytical chemktrv were reviewed. Chromium. Temperature limits suitable for the igiiiti~iiof sonic t w ' i i t v chromium precipitates were recorded by D U ~ I I I G and Duval (35). .4 precipitate of Cr203.3E-120was formed by addition of aminonla gas. The monohydrate could be obtained by means of thiosemicarbazide or cyanate. In the absence of chloride ion ehromium could be determined as mercury(1) chromntcl. Ag20 Cr203was formed during the decomposition of Rilver vhromate. Penchev (1 15, 126) discussed the sourccs of positivr. errors in the gravimetric determination of chromium as chromic(II1) oxide. -411ignitiou temprwdure of about 1O00" was recommended for preripitatcls of rhroniium hydroxide o r mercurv(1) chromate. For drtpr mination as chromium(I11) oxide, an ignition t e m p r a t u r e o f wl)out 850" gave higher valuep than did heating to about 1030" Dupuis and Duval (S:) rerommrnded temperatures al)ovc~671 ' for ignition of mercur] (I) rhiomate. For ignition to chromium(II1) oxide of precipitates obtained by about ten methods, the highest safe minimuni heating temperature was 880". Molybdenum and Tungsten. .4c~sording to Feigl ( 4 7 ) , ?rid fluoiidr. soluf ion interfered n i t h all the preripitation and volar iwrtions of molvbdate and tungstate ions, and n i t h moht of thtws rt~nrtionsof vanadate ion. The maiking effect of fluoride ion applied hv Rudanova :inti Ch\rilova (20) for the heparatiou h l cvpftwoii of tungsten i i i d iiiol)ium in the analysis of steel R u s ( ~ i61). i T - b d w and T.orientc Gonzales (-32)discussed the formation and application to gravimetric analysis of insoluble compounds fornird b\ o-dianisidine with tungstates. Lambie ( P i ) madc a critic.:tl study of vveral methods for separating tungsten and armiic The best procedure involved the removal of xrscwic H Q tht t i i v l Intide, but a c ~ ~ i r art..nlti tc~ tould also be obtaincd bl
V O L U M E 23, NO. 1, J A N U A R Y 1 9 5 1 t!ie tannin-phenazone method or by removing arsenic as the tri,ulfide from sulfuric acid solutions containing tartrate. Precipi1.1 ting tungsten trioxide from acid solutions containing cinchonine ilways yielded low values. Ousev and Kumov ( 6 7 ) examined iiiethods of dissolving alloys of tungsten, etc., which avoided the necessity of using platinum ware. A successful alternative to !I drofluoric and nitric acid treatment was one involving the (1-8 of saturated oxalic acid and 30y0 hydrogen peroxide. Tung.ten was reprecipitated with equal efficiency by cinchonine or pvramidone. Various mcthods have bcrn recorded for determining tungsten Arid molybdenum in steels. Malov (101) measured the density of the alloys. The variations resulting from the presence of ,tlicon, carbon, sulfur, phosphorus, manganese, and molybdenum ere discussed. Jaboulay (81) separated impure tungsten(V1) 11\ide from a hydrochloric acid solution of the steel and sub.tsquently treated the oxide to isolate molybdenum(1V) sulfide. The tungsten was determined by difference. The filtrate was treated to determine molybdenum as lead molybdate. Ruimonte (127) obtained satisfactory results by precipitation and weighing 14 lead molybdate in the analysis of steels containing carbon, t hromium, manganese, nickel, silicon, tungsten, and vanadium. Golubsova and Shemyakin (59) recommended benso [f ]quinoline (3-naphthoquinoline) for the determination of molybdenum in steels in concentrations of 0 45 to 35%. Separation from tungjten was accomplished by adjusting to a weakly arid medium. Cation exchange resin was used hy Ustrenko and Datsenho I f,52) to isolate molyhdenum in the analysis of ferromolybdenum. From a hydrochloric acid medium molybdenum could he separJted from all but traces of iron. Manganese. RIedoks and I\I:irbclova (105) used tetraphenyl phosphonium nitrate to drhtt,rtnine manganese after oxidation N ith ammonium peroxydisulfate to produce the permanganate ion. The precipitate was dricd over sulfuric acid in a vacuum. heelakantam (108) precipitated divalent manganese by 3-quinolinol in ammoniacal solution. Zagorchev (163) found that -?odiumor ammonium acetate did not interfere in the precipitation of ammonium mangancse phosphate monohydrate. For the pi tacipitation of manganesc in the complete analysis of mangunese ore, Semenko (136) treated the acid solution of a manqanese ore with aqueous ammonia free of carbon dioxide, filtered quickly, and added potasRiuni prrmanganate to produce mang n e s e dioxide. Nickel. Further data have been added to the literature deali ~ i gwith 1,2-cyclohexanedionedioxime as a reagent for nickel. 'l'here exists some cotitradirtion concerning the possibility of 1 lirninating interference from iron. Peshkova, Vedernikova, i r i d Gontaeva (116) reported thzt iron could be fixed by tartrate 0 1 removed as a prccipitxte by sodium fluoride. Difficulties en< ountered with the coagulation of the nickel complex were over( w n e by addition of ammoniurii chloride or nitrate. Interference %om cobalt was avoided by adjusting the p H to about 3 23 n i t h .;idirim acetate. In the routine determination of nickel in cobaltI ~ i s ealloys Silverman and 1,cnit)crsky (140) evaporated to fumes the perchloric acid solution of the alloy, buffered n i t h citrate arid ammonium hydrouide, oxidized cobalt and manganese with potassium hexacyanoferratP(IIT), and precipitated nickel in an r thy1 aleohol medium by dimethylglyoxime. The nickel dirnethylglyoxime was reprecipitated. Liang and Chang (96) etated that copper and cyanide interfered with the precipitation of nickel dimethylglyo.rimt~. Oapenson (112) recommended a vdriety of surface active agerite such as Vel, Triton, etc , to hasten filtration and prevent "crawling" of nickel dimcthylglyoxime. T m a n a e v and Levina (f45)studied the system nickel sulfatenugnesium ferrocyanide-water. They concluded that of the alkali metals only lithium ferrocyanide was suitabk for the precipitation of nickel ferrocyanide. Coprecipitation of alkali metals with nickel cyanoftlrrate(I1) decreasrd from cesium to lithium in Column T.4.
63 NONFERROUS ELEMENTS
Copper and Cadmium.
Tarasevich (147) used o-phenyldiamine to precipitate copper. The precipitate, whose composition was C U [ C ~ H ~ ( N H ~ ) ~ ] ~ S could O ~ . H be ~ Odried ~ in a desiccator or by heating a t 105" to 110". In a second publication (148) he described the application of phenylenediamine together n-ith potassium tetraiodomercurate(I1) to produce insoluble Cu [ C J L (NH2)J2Hg14 nhich was dried a t 105' to 110' and weighed. There was no interference from cadmium, zinc, nickel, and cobalt when these cations did not exceed 25%. Trivalent iron, chromate, and other oxidizing reagents interfered. Mercury could be determined similarly h y reversing the procedure for copper. Dey (29) discussed the conditions of precipitation of copper(I1) hydroxide from solutions of copper sulfate. Excess of sodium hydroxide produced a precipitate totally insoluble in aqueous ammonia solutions. For the analysis of mixtures of copper(1) oxide, copper (11) oxide, and metallic copper, Ubaldini and Guerrieri (161) converted the metallic copper to sulfide by treatment of the mixture with a solution of sulfur in carbon disulfide. The oxides of copper were then differentially dissolved out of the mixture by potassium chloride in hydrochloric acid. Sarudi (131) separated copper from cadmium by precipitation of copper sulfide by sodium thiosulfate. The precipitate was redissolved by fusion with potassium pyrosulfate, reprecipitated, arid ignited to copper oxide. The cadmium was determined as sulfidr~or pyrophosphate. For the separation of cadmium from Iaryc quantities of 2111r, Barker, Cahill, and Young ( 6 ) used a zinc reduction method followcd by precipitation of cadmium sulfide. Gusev (66) used an antipyrine-bromide reagent for the detection and determination of cadmium. In quantities usually present there n-ae no interference from magnesiuni, aluminum, iron, zinc, coppcr, bismuth, lead, mercury, antimony, and tin. The data provided suggested that the precipitate is appreciably solublc in the precipitating and washing media, Silverman (139) discussed methods used in analyzing cadmium plating solutions. Gallium, Thallium, and Indium. Dupuis and Duval ( - 3 3 ) recorded the minimum temperatures necessary for converting gallium precipitates to gallium trioxide. Precipitation of the hydroxide by ammonia and also the camphorate methods iwre considered excellent, although the latter could not be used in the presence of iron and indium. Precipitations by cyanoferrate( 11) or 8-quinolinol were not recommended. Sodium sulfite heptahydrate was a satisfactory reagent for the separation of gallium from iron. Dupuis and Duval(54) also recorded suitable ignition tenipcratures for various indium preripitates. Indium(I1) sulfide offered a new possibility for automatic determination. The 8-quinolate and cyanate methods were recommended. Feigl and Baumfeld (48) outlined procedures for the gravimetric determination of trivalent thallium by gquinolinol and 2,5dibromo-&quinolinol. The 5,7-di,ronio-8-quinolinate of gallium, according t o Dupuis and Duval (SS), could be ignited to gallium trioxide a t 817" or the anhydrous prwipitate could be weighed after drying a t 100" to 224". Tin and Lead. Foschini (.if) found that precipitatioti of t i n sulfide from hydrochloric acid solutions of tin( IT)chloride ( W I I taining large amounts of oxalic acid was not complete. The intct ference was eliminated by partial evaporation in the presence of hydrogen peroxide. Putzmann (192) discussed the limitations of the method of determining lead previously recorded by Tananaev and hfisetskaya (146). Working with nonferrous alloys, he found that the precipitate was lead sulfate and not a double salt of potassium and lead sulfate. The presence of excess potassium sulfate resulted in adsorption, and mineral acids, especially nitric acid, interfered. However, if thallium(1) sulfate was used instead of potassium sulfate almost quantitative precipitation of T1,Pb(S04)~resulted. Hovorka and Divis (76) found 2-isatoxime useful for the gravimetric determination of lead.
ANALYTICAL CHEMISTRY
64 01 galen:i, Yarudi (132) treated the' saniplcs with hydrochloric aiid pcrchloric acids, followed by addition of nitric acid. The lead was precipitated as sulfide, which ivas wished with water, ether, and carbon disulfide, and weighed after drying a t 100' to 110". Sniythe (141) used :I dry mothod for the determination of lead in galena, oxides, etc. The sample was fused with potassium hydroxide and t,reatcti with tin(I1) sulfide to produce a "weighable" lead button. Hisniuth as oxide or sulfide could be treated similarly. The results compared favorably with those ~ b t ~ a i n eby d wet methods. Schafer (133) deterniined lead iii its oxide by reduction with hydrogen at 500" and 600". Busev (23) published a critical review of methods of separation of bismuth and lead. Arsenic and Antimony. Dupuis and Duval (38) recorded heat stability ranges for the following arsenic precipitates : lead orthoarsenate and pyroarsenate, bismuth orthoarsenate, and silver thallium arsenate. According to Jean (SP), precipitation of orthoarsenic acid by an excess of quadrivalent zirconium could not be recommended as a n analytical procedure. The coiiiposition of the precipitate was not, constant but :ipproached
3ZrO2.AszO6. Olea Goniez and Gaspar Romero (110) discuswd mc~thotlsfor determining ant,iiiiony-in particular, precipitatioii by S-quinolinol and gallic acid. Thr, latter formed an insoluble complex u-ith trivalent antimony. In the presence of k:id the sulfuric acid solution was tre:tted with potassium sodiuni t:trtr:Lt
