Determination of cobalt and nickel by graphite-furnace atomic absorption spectrometry after coprecipitation with scandium hydroxide

Determination of cobalt and nickel by graphite‑furnace atomic absorption

spectrometry after coprecipitation with scandium hydroxide

著者 Minami Tomoharu, Atsumi Kousuke, Ueda Joichi journal or

publication title

Analytical Sciences

volume 19

number 2

page range 313‑315

year 2003‑01‑01

URL http://hdl.handle.net/2297/3904

ＡＮＡＬＹＴＩＣＡＬＳＣＩＥＮＣＥＳＦＥＢＲＵＡＲＹ２００３,VOL19

2003oTheJapanSocietyfOrAnalyticalChemistry

313

DetelminationorCobaltandNiclKelbyGraphite-Fumace AtomicAbsorptionSpectrometryanerCoprecipitation withScandiumHydmxide

ｎｍｏｈａｒｕＭＩＭＭＩ,KousukeATsuMI,andJoichiUEDA

HZc"JZycl/、/"carjo",肋"αＺａｗａＩ/7zjvelmMmﾉh"７ｚａｍａｃ/ｚｉ,肋"αZawq920〃92,ＪZIPα〃

TraceamountsofcobaltandnickelinawatersamplewerequantitativelycoprecipitatedwithscandiumhydroxideatpH ８０－１０．５．Becausethecoprecipitantcouldbeeasilydissolvedwithlmoldm-3nitricaci｡,ａｎｄｔｈｅｐｒｅｓｅｎｃｅｏｆｕｐｔｏｌＯ ｍｇｃｍ－３ｏｆscandiumdidnotinterferewiththegraphite-fnmaceatomicabsoIptionspectrometricdetenninationofcobalt

andnickel，thevolumeofthefinalsolutionpreparedfOrthedetenninationcouldbeminimizeddowｎｔｏＯ５ｃｍ３・Ｔｈｅ

concentrationfactorwas400-fOldandthedetectionlimits(signaltonoise＝２)ｗｅｒｅ５.Opgcm-3ofcobaltandlO・Ｏｐｇ ｃｍ－３ｏｆｎｉｃｋｅｌｉｎ２００ｃｍ３ｏｆｔｈｅｉｎitialsamplesolutionThe27diverseionsinvestigateddidnotinterferewiththe detemlinationinatleasta500-fOldmassratiotocobaltornickeLTheproposedmethodwassuccessfUllyappliedtothe detelminationoftraceamountsofcobaltandnickelinliver-watersamples、

(ReceivedSeptember27,2002;AcceptedNovember27,2002）

ThecoprecipitationmethodisusefillfOrtheconcentrationof tracemetalions，andhasoftenbeencombinedwithgraphite- fUrnaceatomic-absolptionspectrometryfOrthedetenninationof thetracemetalions・Inapreviouspaper,’weproposed scandiumhydroxideasanexceUentcoprecipitantfOrsome metalions，suchascopper,lead，ａｎｄｃａｄｍｉｕｍ，becauseofits goodcollectingabilityandeaseofdissolutionindilutemineral acids,anddemonstratedthedetenninationofatraceamountof copperuslnggraphite-fnmaceatomicabsolptionspectrometry combinedwiththescandiumcoprecipitationtechnique、Ｔｈｉｓ time，wefOundthatscandiumhydroxideisalsoagood coprecipitantfOrtraceamountsofcobaltandnickel,andthatthe coprecipitatedmetalionscanbedeterminedsatisfactorilyby graphite-fUmaceatomicabsorptionspectrometry，evenunder thepresenceofalargeamountofscandium・Sincescandium hydroxidecouldbeeasilydissolvedindilutenitricacid，the finalsamplevolumepreparedfOrthedeterminationcouldbe minimiｚｅｄｄｏｗｎｔｏＯ５ｃｍ３,andhencetheconcentrationfactor ofcobaltandnickelreached400-fOldThemethodproposed heIcissimpleandreproducible

Untilnｏｗ,avanetyofcoprecipitantshavebeenproposedfOr theconcentrationofboIhcobaltandnickelpriortothe detenninationbygraphite-fUrnaceatomicabsolption

spectrometry､2-9However，amethodusingzirconium hydroxide2requiresheatingtodissolvethecoprecipitant，and

theuseoftin(1V)hydroxide3makesitnecessarytobeaUowed tostandthefinalsolutionovernighttolemovethetincarrier・

Theuseofiron(ⅡI）tetramethylenedithiocarbamaterequlresa longdigestionoftheprecipitateinordertosimplifythesample matrix,４ordestroyingthescumobtainedbytheflotation technique5Althoughindiumhydroxide6,７isanexcellent collector，indiumitselfcausesseriousbackgroundabsorption Toeliminatebackgroundabsorption，therefOre，the minimizationoftheindiumamount6andthevolatilizzationof

indiumasbromideduringtheashingstage7weretried Althoughmagnesiumoxinate8isalsoaneffectivecollector，

precipitationshouldbeencourageｄbyheatingwhenseawateris analyze｡．AmmoniumpyITolidinedithiocarbaｍａｔｅ（ＡＰDC）of copperandiron9isdissolvedonlyslowly、

Forthepreconcentrationofcobaltalone，magnesium8- quinolinateloandnickel8-quinolinol/l-nitroso-2-naphthol complexIIhavebeenproposed，givingextremelyhigh concentrationfactors、Inthesemethods，thecoplecipitatesare submittedtoanalysiswithoutdissolutionAlso，intheuseof disulfidel2fOrcobaltcollectioLthesuspensionofthe coprecipitateisinjecteddirectlyintoagraphitefUrnace・Ｔｈｅ ｕｓｅｏｆｉｒｏｎ(Ⅲ）hexamethylenedithiocarbamatel3fOrcobalt determinationandtheuseofiron(Ⅱ）diethyldithiocarbamatel4 andcobaltAPDCl5fOrnickeldetelminationrequlrealong digestionofthepIecipitatestosimplifythesamplematrix

ThispaperdescribesthefUndamentalconditionsfOrthe coprecipitationoftraceamountsofcobaltandnickelinwater withscandiumhydroxideandfOrthedetelminationofthese ionsbygraphite-fUmaceatomicabsolptionspectrometry．

Experimental

Appamt"s

AHitachil70-70Zeemanatomicabsolptionspectrometer withaHitachicobaltornickelhollow-cathodelampwasused fOratomicabsolptionmeasurements・Theoptimumoperating conditions，whichwerestudiedusingasolutionobtainedby coprecipitationaccordingtotherecommendedprocedulefrom distilledwatercontainiｎｇｌＯＯｎｇｏｆｃｏｂａｌｔａｎｄｎｉｃｋｅｌ，ａｒｅ ｓｕｍｍａｒｉｚｅｄｉｎＴａｂｌｅＬＦｏｒｐＨｍｅａｓurements，aHitachi- HoribaModelM-5glass-electrodepHmeterwasused Reage"zs

CoZMI/ｒａＭ〃jcIceノｓｏﾉzltjo〃Asolutioncontainingaboutlmg cnr3ofcobaltornickelwaspreparedbydissolvingguaranteed reagent-grademetalnitrateinasmallamountofconcentrated

ＡＮＡＬＹＴＩＣＡＬＳＣＩＥＮＣＥＳＦＥＢＲＵＡＲＹ２００３,ＶＯＬ１９ 314

nblelOperatingconditionsfOrtheatomic-absorption spectrometer

Ｎｉ

100 ＣＯ

奉言三つ弓』

Analytical wavelength Lampcurrent Slitwidth

Argongasflowrate Sheathgas CalTiergas Injectionvolume

Cuvette

241.6,ｍ 232.0,ｍ

７５ｍＡ No.３(2.2,ｍ）

ｌＯｍＡ Ｎｏ､３(2.2,ｍ）

9０ _{３ｄｍ３ｍｉｎ－ｌ ３ｄｍ３ｍｉｎ－ｌ}

Ｏｄｍ３ｍｉｎ－ｌ Oｄｍ３ｍｉｎ－ｌ

１０ｍｍ３ １０mm3

UncoatedtubetypeUncoatedtubetype graphitefUmacegraphitefUmace 24A(cα､190°Ｃ),４０ｓ２４Ａ(cα､190°Ｃ),４０ｓ 80Ａ(cα･900℃),３０ｓ８０Ａ(cα､900°Ｃ),３０ｓ 310Ａ(cα､2830°Ｃ),５ｓ３１０Ａ(cα2830°Ｃ),５ｓ ６

Scandium/川

10 ２

Dryingconditions Ashingconditions Atomizing

conditions

Fig.１Effectoftheamountofscandiumontherecoveryofcobalt ornickelfrom200cm3ofasamplesolutioncontainingllJLgofcobalt (○）ornickel（●)．CoprecipitationwascarriedoutatapHofabout 9､5,andthefinalsamplevolumewasmadeｕｐｔｏｌＯｃｍ３．

reconmended:takinglOmm3ofthefinalsolution,theamount ofcobaltornickelinit(ＭIng)ismeasuredbygraphite-fUrnace atomicabsolptionspectrometryundertheoperatingconditions giveninTableLTakinganotherportionofthesolution（Ｖ ｍｍ３),ｔｈｅａｍｏｕｎｔｏｆｓｃａｎｄｉｕｍｉｎｉｔ（Ｓｍg）ismeasuredby complexometrictitrationusingXylenolOrangeasanindicatom Ablankisalsorunusingdistilledwaterasasamplesolution Thecontent(Ｍｂｎｇ)ofcobaltornickelintheoriginalsample solutioniscalculatedusingthefOllowingequation：

０ １ ０

室一｛』・二つ》空］

9０

1０ ９

８

Ｍｂ＝Ｍ１×(Ｗ10)×(4/S)．

Fig.２EffectofthepHontherecoveryofcobaltornickelfiom200 cm3ofsamplesolutioncontainingllLgofcobalt（○）ornickel（●)．

FourmilligeamsofscandiumwereusedfOrcoprecipitation，andthe

finalsamplevolumewasmadeｕｐｔｏｌＯｃｍ３． ResultsandDiscussion

SZ"｡)Ｗ此op伽"、ＣＯ"伽o"s/brc叩rEcjpjjarjo〃

Ｕｐｏｎaddingvanousamountsofscandium，itsnecessaIy amountfOrcoprecipｉｔａｔｉｏｎｗａｓｅｘａｍｉｎｅｄｗｉｔｈ２００ｃｍ３ｏｆa samplesolutionspikedwithlugofcobaltornickeLForthe fmnationofscandiumhydroxide,ｔｈｅｐＨｏｆｔｈｅｓａmplesolution wasadjustedtoabout9.5ｗｉthaO1moldnr3sodiumhydroxide solutionTheprecipitateproducedwascollectedona3G4 sintered-glassfilter，washedwithasmallamountofdistined water，ａｎｄｄｉｓｓｏｌｖｅｄｗｉｔｈ２ｃｍ３ｏｆｌｍｏｌｄｍ－３ofnitricacid ThesolutionwasthenｍａｄｅｕｐｔｏｌＯｃｍ３ｗｉｔｈｌｍｏｌｄｍ－３ｏｆ ｎｉｔricacid，andtheabsorbancesofcobaltandnickelwere measuredundertheoperatingconditionsgiveninTableL FromtheresultsshowninFig・Lmorethan2mgofscandium wasrequiredfOrquantitativerecoveries・Ｔｈｅｐｒｅｓｅｎｃｅｏｆｕｐｔｏ ｌＯｍｇｃｍ－３ｏｆｓｃａndiumdidnotaffecttheatomicabsolptionof cobaltornickeLThus,４ｍｇｏｆｓｃａｎｄｉｕｍｗａｓｕｓｅdinfUrther experiments・TheoptimumpHrangefOrthecoprecipitation was8,０－１０．５(Fig.２)．Therefbre,thepHofthesolutionwas adjustedtoabout95withasodiumhydroxidesolutionThe recoveriesofcobaltandnickelwerehardlyinHuencedbythe standingtimeoftheprecipitate・Thus，almostcomplete recoveneswereobtainedfTomafewminutesto5hofStanding．

nitricacidanddilutingwithdistilledwater、Theconcentrations ofbothcobaltandnickelweredetenninedbycomplexometnc titrationusingXylenolOrangeandMurexideasindicators，

respectively、

Scα"djLmzso〃jonAboutal5mgcm-3scandiumsolutionwas preparedbydissolvingscandiumnitrate(NacalaiTesque,Inc.）

indistilledwater、Thescandiumconcentrationwasdetｅｌｍｍｅｄ

ａｔａｐＨｏｆａｂｏｕｔ２ｂｙｃｏｍｐｌｅｘｏｍetrictitrationusmgXylenol Orangeasanindicator・

Allotherreagentsusedwereofguaranteedreagentgrade．

Recomme"dCapmcecmre

Toasamplesolution(ｕｐｔｏ２００ｃｍ３)containinguptolOOng ofcobaltand200ngofnickeL4mgofscandiumisadded exactly,andthepHofthesolutionisadjustedtoabout9Swith a０．１moldnr3sodiumhydroxidesolutionTosettlethe producedprecipitate，thesolutionisallowedtostandfOrafew minutes;theprecipitateisthencoUectedonaToyoRoshiPTFE membranefilter(poresizeO,511ｍ,diameter25mm),filteredby suction，washedwithasmallamountofdistilledwater，ａｎｄ ｄｉｓｓｏｌｖｅｄｗｉｔｈＯ５ｃｍ３ｏｆｌｍｏｌｄm-3nitricacid・Theatomic absorbancesofcobaltandnickelweremeasuredunderthe operatingconditionsgivenmTableLAblankusingdistilled waterwasrunaccordingｔｏｔｈｅｓａｍｅｐｒｏｃｅｄｕｒｅａｓｔｈａｔｆＯｒthe samplesolutionlnthisworktheblankcouldbeneglectedin mostinstancesbecauseitwasextremelysmaｌＬ

ＩｆｉｔｉｓｄｉｆｆｉｃｕｌｔｔｏｍａｋｅｕｐｔｈｅｆｉｎａｌｖｏｌｕｍｅｔｏＯ・Scm3with goodreproducibility，thefO11owingmeasurementis

DjssoMo"q/ｒｈｅｐ花cjp加花

Scandiumhydroxidedissolveseasilyincommonmineral acids・Theeffectoftheconcentrationofnitricandhydrochloric

acidsontheatomicabsorbanceofcobaltornickelwas examined・Anincreaseintheconcentrationoftheseacids

graduallydecreasedtheabsorbances・ ＨｏｗｅVer，the absorbancesofbothmetalionsbecamealmostconstantinthe

ＡＮＡＬＹＴＩＣＡＬＳＣＩＥＮＣＥＳＦＥＢＲＵＡＲＹ２００３,ＶＯＬｌ９ ³¹⁵

Table2Effectofdiverseionsonthedeterminationof50ng ofcobaltornickel

Table４Resultsofthedeterminationofcobaltandnickelin watersamples

MaSSratiOa [IC､]/[ＣＯ]ｏｒ[Ni］

CalibrationmethodStandardadditionmethod

IC、 Locationof

samplingpoint ^CofOund／

ｎｇＣｍ－３

NifOund／CofOund／NifOund／

ｎｇｃｍ－３ｎｇｃｍ－３ ｎｇｃｍ－３

1200000 500000 250000 ５００

Ｎａ十 Ｋ＋

Mg2iCa2+

Li+,Srz+,Ｂａ2+,Ａｌ3+,Ga3十,1,3+,Sn4+,Ｐｂ2+，

Sb3+，Ｂｉ3+，Ｃｕ2+，Ｚｎ2+，Cd2+，La3+，Ｃｅ3+，

Zr4+,Movl,WvI,Cr3+,Ｍｎz+,Fe3+,Ｐｔ'v,Aulll

River

(upperstream）

Asano Sai Kanakusari Branchof

Gohtani Seashore

Kanaiwa

0.050 0.034 0.096

0.27 0.066 0.26

0.049 0.038 0.086

0.26 0.068 0.30

ThecoprCcipitationwascarriedｏｕｔｆｉｒｏｍａｂｏｕｔ５０ｃm3ofthesample solutionatpHabout9.5．

a・Ｔｈｅｅｒｍｒｓａｒｅｗｉｔｈｉｎ±5％．

4.15ａ２.O2b4.22ａ2.13ｂ

Ｎ.，．0.23Ｎ､，．０．２４ Ｔｈｅｓａｍｐｌｅｖｏｌｕｍｅｔａｋｅｎｗａｓ２００ｃｍ３ａｎｄＯ５ｃｍ３ｏｆｌｍｏｌｄｍ－３ ｎｉｔｒｉｃａｃｉｄｗａｓｕｓｅｄfOrdissolutionoftheprecipitate、Theobtamed resultsaretheaverageofthreereplicatedetenninations．Ｎ、，.：not detected

a,ＴｈｅｆｉｎａｌｖｏｌｕｍｅｗａｓｍａｄｅｕｐｔｏｌＯｃｍ３withlmoldm-3nimcacid bThefinalｖｏｌｕｍｅｗａｓｍａｄｅｕｐｔｏ５ｃｍ３withlmoldm-3nitricacid．

Table3Recoveryofcobaltandnickelfromspikedwater sampIes

ＣＯ Ｎｉ

Sample volume／

Ｃｍ３ Added／Recovery，

、９ ％ ＲＳＤ，Added／Recovery，ＲＳＤ，

％、９％％

Riverwater ２００５ ２００５０ ２００１００ Seawater

２００５ ２００５０ ２００１００

98.8 99.6 99.2

７３０ ●●● ８５４

１０ １００ ２００

97.3 100.5 100.1

５７８

●●● ７５５

analysesofwatersamplescontainingdｏｗｎｔｏ５ｎｇｏｆｃｏｂａｌｔ ａｎｄｌＯｎｇｏｆｎｉｃｋｅlin200cm3oftheinitialsamplesolution

Basedontheaboveexpenments,detenninationsofcobaltand nickeｌｉｎｒｉｖｅｒａｎｄｓｅａｗａｔｅｒ（locatedinIshikawaprefecture）

weretriedThesampleswerefilteredthroughaToyoRoshi TM-2pmembranefilter（poresizeO､4511ｍ）andanalyzedas soonaspossibleaftersamplingTheresultsobtainedbythe calibrationandstandardadditionmethodswereingood agreement,althoughcobaltinseawaterwasnotdetected(Table 4)．

103.2 ９８．８ ９９．６

1０．５ ９．５ ８．７

１０ １００ ２００

100.6 10ＬＯ ９９．７

２８５

●●● ６３４

Therecoveneswerecalculatedbysubtractingthepeakheightdueto theｗａｔｅｒｓａｍｐｌｅａｌｏｎｅｆｒｏｍｏｎｅｄｕｅｔｏａｗatersamplespikedwith cobaltornickeLTheobtainedrecoveriesaretheaverageofthree replicatedetenninations．

References rangeｏｆＯ４－２ｍｏｌｄｍ－３ｏｆｎｉｔｒｉｃａｃｉｄａｎｄ０．５－L5moldm-3of

hydrochloricacid・Inthisstudy，lmoldm-3ofnitricacidwas usedfbrthedissolutionofscandiumhydroxide．

ＬＪ､ＵｅｄａａｎｄＴ､Minami,ｄｊｅｍ.LerL,1997,681.

2.Ｓ、NakashimaandM・Yagi,Ａ"α/､血".，1984,ノ7(AI5)，

１６９３．

３．MHiraide,ＺＳ・Chen,Ｋ・Sugimoto，ａｎｄＨ・Kawaguchi，

Ａ"α/､Ｃ/Z〃.ＡＣ、,1995,302,103.

4.Ｖ・Hudnik,SGomiscek,andBGorenc,Ａ"α/､Ｃ/j伽.Ａｃｍ，

1978,98,39.

5．KCundevaandTStafilov,Ａ"αﾉ.Letr.,1997,30(ｷﾞﾉ,８３３．

６．Ｍ．Hiraide，Ｚ．Ｓ、Chen，ａｎｄＨ・Kawaguchi，Ａ"αﾉ．Sci.，

1995,〃,３３３．

７．ＺＳＣｈｅｎ，MHiraide，ａｎｄＨ・Kawaguchi，Ｂ""Scハノ KZJgaA",1993,苧2,759.

8．ＺＳ・Chen，MHiraide，ａｎｄＨ・Kawaguchi，Mjlbqoc/z伽 ＡＣ、,1996,ノ2ｲ,２７．

９．Ｒ､Ｗ・Dabeka,Scj､刀ZZJlE>Ｍｒｏｎ,1989,89,271.

10.Ｋ．Akatsuka，Ｎ・Nobuyama，andLAtsuya，Ａ"α/、Ｓｃｊ.，

1989,5,475.

11.Ｑ・Zhang,HMinami,SInoue,ａｎｄ1.Atsuya,Ａ"α/､Ｃｈ伽 ＡＣ、,2000,午０７，１４７．

１２．Ｍ.Hiraide,ＺＳＣｈｅｎ,ａｎｄＨ・Kawaguchi,乃〃"/α，１９９６，

ィ３，１１３１．

１３．Ｋ.Cundeva,TStafilov,andGPavlovska,Ｍ/c'ROC/tem・ノ.，

2000,65,165.

14Ｈ・Nishioka,Ｓ・Assadamongkol，Ｙ・Maeda,ａｎｄＴＡｚｕｍｉ，

Ⅳjppo〃肋ｊＭＧａＡｊｔａｊｓ/ｚｊ,1987,ギ０，２８６．

１５．ＥＡＢｏｙｌｅａｎｄＪ・MEdmond,Ａ"α/､Ｃﾉﾛ伽Ａｃｒａ,１９７７，９１，

１８９．

ＱＪﾉﾉb'ｍｉｏ〃ｃⅢハノes

Straightlinespassjngthroughtｈｅｏｒｉｇｉｎｗｅｒｅｏｂｔａｉｎｅｄｕｐｔｏ ｌＯＯｎｇｏfcobaltand200ngofnickelinthefinalsolutionusing therecommendedprocedureTherelativestandarddeviations obtainedfromfiverepeateddetenninationswere4.7％ａｎｄ5.7％

ｆＯｒ５０ｎｇｏｆｃｏｂａｌｔａｎｄｎｉｃｋｅｌ，respectively・Thedetection limits(signal/noise＝２)were５．０pgcm-3ofcobaltandlO・Opg cm-3ofnickelin200cm3oftheinitialsamplesolution．

〃e旅re"ces

AccordingtotherecommendedprocedurQtheeffectof27 fOreignionｓｏｎｔｈｅｄｅｔｅｎｎｉｎａｔｉｏｎｏｆ５０ｎｇｏｆｃｏｂaltornickel wasexaminedTable2showsthatlargeamountsofsodium，

potassium，magnesium，andcalciumdidnotinterferefOrboth detenninations・Nootherionstestedproducedanyserious interferenceeffect,evenataconcentration500-timesthemass ofcobaltornickelpresent．

RecoveriesqfcoM1α"｡"icM/)℃mSpjkedwarersamp/es Theutilityofthepresentmethodwasevaluatedbyexamining

therecoveriesofcobaltandnickelfromriverandseawater

spikedwiththesemetalions・Ｔｈｅobtainedresultsaregivenin Table３，indicatingthattheproposedmethodisapplicableto