Coprecipitation of trace metal ions in water with bismuth(III) diethyldithiocarbamate for an electrothermal atomic absorption
spectrometric determination
著者 Sato Hirotoshi, Ueda Joichi journal or
publication title
Analytical Sciences
volume 17
number 3
page range 461‑463
year 2001‑01‑01
URL http://hdl.handle.net/2297/3905
、卓０Ｊ戸』ⅢｗＤＡＡＬｍＬ月△「、』
ＡＮＡＬＹＴＩＣＡＬＳＣⅢＮＣＥＳＭＡＲＣＨ２００１,ＶＯＬ､１７ ２００１．TheJapanSocietyfOrAnalyticalchemistry
461
Nofes
７
CoprecipitationofHaceMetallonsinWaterwithBismuth(Ⅲ）
DiethyldithiocarbamatehranElectrothermalAtOmic AbsoIptionSpectrometricDeterminatiOn
Ｔ
HirotoshiSAToandJoichiUEDA↑
FlZc"/‘)ﾉq/nmcarjo",肋"αＺａｗａＵ"んemtMZJ肋ｍａｍａｃ/zi,Ｋα"αZaWa920L〃92,ﾉﾋJPq〃
(ReceivedNovember7,2000;AcceptedNovember30,2000）
Electrothennalatomicabsorptionspectrometrycombinedwith preconcentrationtechniqueshasbeenwidelyusedfOrthe deternnnationoftracemetalions・Amongthepreconcentration techniques，thecoprecipitationmethodisausefUlmeansof enrichment,andvariouscoprecipitantshavebeenproposed・We havebeeninvestigatinganewcoprecipitantoftracemetalsin waterfOrtheelectrothennalatoncabsorptionspectrometric determination，andhavefOundthatbismuth(Ⅲ）
diethyldithiocarbamate（bismuth(Ⅲ）ＤDTC）hasagood collectingabilityfbrlead,copper,cadmium,cobalt,andnickeL However,ithardlycoprecipitatesmatrixions，ｓｕｃｈａｓｓｏｄｉｕｍ，
potassium,magnesium,andcalciumltisthusapplicabletothe determinationoftheabove-mentionedfivemetals．Also，
bismuth(111)DDTCcanbeeasilydissolvedwithnitricacidln previouspapers,Ｌ２ｗｅｓｕｇｇｅｓｔｅｄｔｈａｔｎｉｃｋｅｌＤＤＴＣｉｓａ conveniemcoprecipitanttohandle,becauseitcanbedissolved inabout8Mnitricacidandacetonewithoutanydigestionor heating，whichissometimesrequiredfOrthedissolutionof organicprecipitates・Thebismuth(Ⅲ)DDTCproposedhereis dissolvedmorｅｅａｓｉｌｙｔｈａｎｎｉｃｋｅｌＤＤＴＣ，andhasnotbeen reportedasacoprecipitantfbrtheconcentrationoftraceions，
althoughDDTCcomplexesofvariousmetalions，suchas aluminium(ⅡI),３iron(Ⅱ),４iron(111),５Zinc(II),6,7nickel(11),８ manganese(Ⅱ),gandcopper(Ⅱ)l0havebeenpreviouslyproposed Inthisnote,thefUndamentalconditionsfOrthecoprecipitation oftraceamountsofcobaltinwaterwithbismuth(Ⅲ)DDTCand fOranelectrothermalatomcabsorptionspectrometric determinationofcobaltaredescribed，appendingthatsome othermetalions，ｓｕｃｈａｓｃｏｐｐｅｒａｎｄｃａｄｍｉｕｍ，mayalsobe deternnnedwiththemethodproposedhere．
Concentrationsofcobaltandbismuth(IⅡ）weredeterminedby complexometrictitrationusingMurexideandXylenolOrange asindicators，respectively、Abouta296DDTCsolutionwas preparedbydissolvingsodiumsaltofDDTC（WakoPure Chencals）indistilledwaterandfilteringoutanyinsoluble
materiaL
ResultsandDiscussion
他col′erjeSq/mlzemeZZzJjo"sbyb伽"ﾉﾊ〃)DDTC
TheusefUlnessofbismuth(Ⅲ)DDTCasacoprecipitantwas investigatedaccordingtothecoprecipitationprocedure indicatedintherecomnendedproceduredescribedbelow，
determiningtherecoverypercentagesofsomemetalions、The recoveryofeachmetalionwasdeterminedbyelectrotherlnal atolnicabsorptionspectrometry・Ｆｏｒsodium，potassium，
magnesium，ａｎｄcalcium，however，flameatomicabsorption spectrometrywasusedAsshowninTableLlead,copper, cadmiumcobalt，andnickelcouldbecoprecipitated quantitatively，wmchindicatesthatbismuth(Ⅲ）DDTCis applicabletotheconcentrationofthoseions、Otherions，
especiallysodium，potassium，magnesium，ａｎｄcalcium，were hardlycollected
ルノe伽"α"o"ｑｆｃｏＭｒ
ｈｃｏｍｍｅ"dedpmcedM”．Anaqueoussolutioncontaining5 mgofbismuth(Ⅲ)ａｎｄ２ｃｍ３ｏｆａ２％DDTCsolutionisadded
nblelRecoveriesofsomeionsbybismuth(Ⅲ)ＤＤＴＣ
Experimental
Iｏｎ Added／ｕｇ Recovery，Ion Added／Recovery，
９６１１９ ％
AppamjLls
AHitachil70-70Zeemanatomicabsorptionspectrometer wasusedfOrtheatomicabsolptionmeasurements，andaToa ModelHM-5BSglasselectrodepHmeterfOrpHmeasurements．
Ｎａ十 Ｋ十
Ｍ92＋
Ｃａ2＋
Sn4＋
Pb2＋
Sb3＋
Ｃｕ2十
ｃｄ2＋ ２
２ ０
● ● ００００１０５２０ ００００ ００００ ５５５５
CI3＋
Cr(ＶＤ Ｍｏ(ＶＤ Ｍｎ２＋
ＣＯ２＋
Ｎｉ2十 Ａｕ3＋
Ａｇ十
１９３０ ４４３２５５２４７
●●●●●●●●● ００００２１６９０ ３０５９０ １ １ ５ １
● １１１０１００２ １ ７９８５８０７８ ●●●●●●●● ６８８００９５１ １６６８０９６７ １
ReagemiF
Allreagentsusedwereofguaranteedreagentgrade・A solutioncontainingaboutlmgcnr3ofcobaltorbismuth(Ⅲ）
waspreparedbydissolvingmetalnitrateinasmallamountof concentratednitricacidanddilutingwithdistiUedwater・Ｔｈｅ
IC､swerecoprecipitatedatpHabout9fromaboutlOOcm3of aqueoussolutio､．
十TowhomcolTespondenceshouldbeaddressed
462 ＡＮＡＬＹＴＩＣＡＬＳＣＩＥＮＣＥＳＭＡＲＣＨ２００１,ＶＯＬ､１７
TableZOperatingconditionsfOratomicabsorption
spectrometly Table3Effectofdiverseionsonthedeterminationoflugof
cobalt Analyticalwavelength
LampcunFent Slitwidth
Argongasflowrate Sheathgas Carriergas Injectionvolume
Cuvette
240.7,ｍ ７５ｍＡ No.２(１．１，ｍ）
Massratioa
[IC､]/[Cobalt］ 1０，
925000 600000 250000 125000 10000０ 50000 ５０００ １０００ ５００
Ｃ１－
Ｎａ＋
Ｋ＋
Ｃａ2十
Ｍ92＋
Ｂｒ,1-,ＳＯ４２－
Ｆ ＰＯ４３－
Ｌｉ+，Be2+，Sr2+,Ｂａ2+,Ａｌ3+,Ga3+,,､3+,Sn4+，
Pb2+，Sb3+，Ｂｉ3+,Ｚｎ2+,La3+,Ｃｅ3+,Ｚｒ4+,Th4+，
Cr3+,MovI,WvI,Ｍｎ2+,Fe3+,Ｃｕ2+,Cd2＋
３dm3min-l Odm3min-1 10mm3
uncoatedtubetype graphitefUmace 24A(cα､170℃),４５ｓ ８０Ａ(cα､780℃),４０ｓ 290Ａ(cα2750°Ｃ),５ｓ Dryingconditions
Ashingconditions Atomizingconditions
CoprecipitationwascaniedoutfiPomabout80cm3ofthesample solutioｎａｔｐＨａｂｏｕｔ９
ａ・TheenPorsarewithin±5％．
ま雨昏⑪５８“ 100
becausethemolarratioofbismuth(Ⅲ)toDDTCinthecomplex wasconfinnedｔｏｂｅｌ:３byanelementalanalysis・Therecovery
ofcobaltreachedalmostlOO9i6withinafewminutesafterthe fmnationofbismuth(Ⅲ）ＤDTC，andremainedalmost unchangedwhilｅｓｔａｎｄｉｎｇｆＯｒ５ｈ，Hence,theprecipitatewas
filteredaftersomesettlementhadoccun℃d
Djsso伽o〃ｑ／ｵﾉzecOp”cゎ伽"r、Forthedissolutionof bismuth(Ⅲ）ＤDTC，severalconⅢnonconcentratedmineral acidswereexannned・Asaresult,itwasfOundthatbismuth(Ⅲ）
DDTCdissolvedeasilyinnitricacidAlthoughtheresulting clearsolutionsometimesbecameturbidupondilutionwith distilledwater，itwaspossibletopreventthesolutionfiDm turbiditybytheadditionofasmallamountofacetone・Thus,in thisexperiment，１cm3ofconcentratednitricacidwasusedto dissolvetheprecipitateanｄＯ５ｃｍ３ｏｆａｃｅｔｏｎｅｗａｓａｄｄｅｄｉｎｔｏ ｔｈｅresultantsolution，sinceｔｈｅａｄｄｉｔｉｏｎｏｆＯ２５－２．５ｃｍ３of concentratednitricacidanduptｏ２５ｃｍ３ｏｆａｃｅｔｏｎｅｄｉｄｎｏｔ ａｆｆｅｃｔｔｈｅcobaltabsolption
QJljbmrjo〃ｃ"rve．Alinearrelationship,passingthroughthe origin,betweenthepeakheightandconcentrationwasobtained from０．１－１．５ugofcobaltinthefinalsolution(５ｃｍ3)．The relativestandarddeviationfOrthepeakheightsobtainedfrom fiverepeateddetemⅡnationsｗａｓ0.89％ｆＯｒｌｕｇｏｆｃｏｂａｌｔｉｎ ａｂｏｕｔ３００ｃｍ３ｏｆthesamplesolution，Thedetectionlimit (signaltonoise＝２)wasOO4ngcnr3ofcobaltin500cm3of theinitialsamplesolution．
､ｊｅ族re"cesq/djvemejo"８．Theeffectof33diverseionson thedeternnnationofcobaltwasexaminedusinｇａｂｏｕｔ８０ｃｍ３ｏｆ ａｓａｍｐｌｅｓｏｌｕｔｉｏｎｂｙtherecomnendedprocedure、Table3 showsthatlargeamountsofsodium，potassiummagnesium，
calciumHuoride，chlolide，bromide，iodide，sulfate，and phosphatedidnotintelferewitｈｔｈｅｄｅｔｅnnination・Noother ionstestedproducedanyseriousinterferenceeffect，evenata concentration500-timesthemassofthecobaltpresent・
他coVeK)'qfcoMr伽mSpjkeaware7sam此s、Toevaluate theusefUlnessofthismethod，therecoveriesofcobaltfrom nver，tap，ａｎｄseawatersamplesspikedwithcobaｌｔｗｅｒｅ ｅｘａｍｉｎｅｄＡｓｓｈｏｗｎｉｎＴａｂｌｅ４，theobtainedresultswere satisfactory,anditseemsthattheproposedmethodisapplicable toanalysesofthesewatersampleswhichcontaindowntoO2 ngcnr3ofcobalt・Therecoveriesofcopperandcadmiumwere alsoexaminedandthegoodresultswereobtained(Table４)．
Basedontheresultsobtainedfromtheabove-mentioned experiments，ｔｈｅdeterminationsofcobaltinriver,tap,ａｎｄｓｅａ
5０
0
４ ８ 1２
pＨ
ＦｉｇｌＥｆｆｅｃｔｏｆｔｈｅｐＨｏｎｔｈｅｒｅｃｏｖｅｒｙofcobalt，copper，ｏｒ cadmiumfromaboutlOOcm3ofasamplesolutioncontaininglUgof cobalt(●),ZUgofcopper(□),ｏｒ0.O2ugofcadmium(○)．
withstilTingtoasamplesolution(ｕｐｔｏ５００ｃｍ３）containing O､１－L5Ugofcobalt,andthepHisadjustedtoabout9with about5Maqueousamnonia・Aftertheprecipitatehassettled，
thesolutionisfilteredthrougha3G4sintered-glassfilter・The precipitateiswashedwithasmallamountofdistilledwaterand dissolvedinlcm3ofconcentratednitricacidThen,ａＯ５ｃｍ３ ｖｏｌｕｍｅｏｆａｃｅｔｏｎｅｉｓａｄｄｅｄａｎｄｔｈｅｓｏｌｕｔｉｏｎｉｓｍａｄｅｕｐｔｏ５ｃｍ３
ｗｉｔｈdistilledwater・Theatomicabsorbanceofcobaltis
measuredundertheoperatingconditionsgiveninTable2A blankisalsorun,usingdistilledwaterasasamplesolutio、
Smdjﾉｑ／伽Ｏｐ伽"ｍｃｏ"伽o"ｓ/brcOp”cjpi〃o"、The effectofthepHonthecoprecipitationwithbismuth(Ⅲ)DDTC wasstudiedwithasolutioncontaininglUgofcobalt、The
maximumandalmostconstantrecoveneswereobtainedovera
pHrangeｆｒｏｍ２０ｔｏｌＬ２(Fig.1)．ApHofabout9wasused fOrthecoprecipitationofcobaltinfUrtherexperiments,because theprecipitateofbismuth(Ⅲ)DDTCobtainedaboveapHof about8wasbulky，andhenceeasytohandle・ＩｎＦｉｇｌ，the resultsofcopperandcadmiumarealsoappendedThe necessaryamountofbismuth(Ⅲ)DDTCfOrcoprecipitationwas examinedwithasamplesolution(５０－５００ｃｍ3)containinglug ofcobalt・Therequiredamountofbismuth(Ⅲ)DDTCfbrthe quantitativecoprecipitationincreasedalongwithincreasingthe samplevolume,ａｎｄthecomplexationof4mgofbismuth(Ⅲ）
withDDTCwasnecessaryfOrupto500cm3ofsamplesolution Sincetheatomicabsorptionofcobaltwasnotaffected,ｅｖｅｎｉｆ ｌＯｍｇｏｆｂｉｓｍｕｔｈ(Ⅲ）wasadded,５mgwasusedinfUrther expenments・ＢｅｃａｕｓｅｔｈｅａｄｄｉｔｉｏｎｏｆｕｐｔｏｌＯｃｍ３ｏｆａＺ９６
ＤＤＴＣｓｏｌｕｔｉｏｎａｌｓｏｄｉｄｎｏｔｉｎｔerferewiththecobalt
determination，２ｃｍ３，correspondingtoaboutll-times（asa molarratio)Ｓｍｇｏｆｂｉｓｍｕｔｈ(ImwasusedfOrcoprecipitation，
ＡＮＡＬＹＴＩＣＡＬＳＣＩＥＮＣＥＳＭＡＲＣＨ２００１,ＶＯＬ１７ 463
Table5Resultsofthedetelminationinwatersamples Table4RecoveryfTomspikedwatersamples
Found/ngcIIr3 Sample Added/ug Found/ｕｇ ＲＳＤ,９１６
Sample
Ｒｉｖｅｒｗａｔｅｒ Ｃｏ Ｃｕ Ｃｄ Ｔａｐｗａｔｅｒ
Ｃｏ Ｃｕ Ｃｄ Ｓｅａｗａｔｅｒ
Ｃｏ Ｃｕ Ｃｄ
CalibrationmethodStandardadditionmethod 0.1
0.1 0.015
0.1 0.1 0015
2.37 3.77 9.61
Ｒｉｖｅｒｗａｔｅｒ Ｃｏ Ｃｕ Ｃｄ Ｔａｐｗａｔｅｒ
Ｃｏ Ｃｕ Ｃｄ Ｓｅａｗａｔｅｒ
Ｃｏ Ｃｕ Ｃｄ
Ｎ､Ｄ、
0.32 0.009
Ｎ､Ｄ、
0.32 0.009 0.1
0.1 0.015
0.101 0.1 0015
6.66 3.26
9.76 Ｎ､Ｄ、
2.30 0.007
Ｎ､Ｄ，
2.34 0.007 0.1
0.1 0.015
0.1 0.096 0.0156
6.19 7.05
5.00 0.22
1.16 0.015
0.24 1.06 0.016 Theobtainedresultsaretheaverageofthreereplicatedeterminations
Thesamplevolumetakenwas500cm3．
Theobtainedresultsaretheaverageofthreereplicatedetenninations，
Ｔｈｅｓａｍｐｌｅｖｏｌｕｍｅｔａｋｅｎｗａｓ５００ｃ、３．Ｎ.，.:notdetected．
water(locatedinIshikawaprefecture)weretriedThesamples werefilteredthroughaFlljiPhotoFilmFR-40membranefilter (ｐｏｒｅｓｉｚｅＯ４１ｍｌ）assoonaspossibleaftersamplingand adjustedtopH２．５‐３０ｗｉｔｈconcentratednitricacidTable5 summarizestheanalyticalresults，InthisTable，theresultsof analysesofcopperandcadmiumarealsoappended，indicating thattheresultsobtainedbythecalibrationandstandardaddition methodsareingoodagreement．
４．Ｈ・Nishioka,Ｓ・Assadamongkol,Ｙ・Maeda,ａｎｄＴＡｚｕｍｉ，
ノVippo"肋加ｊＧａ伽杣j,1987,イ０，２８６．
５．Ｆ・Sugimoto,AKimura,Ｙ・Maeda,andTAzumi,Mppo〃
KZzjs"ｊＧａﾉﾋlmshi,1989,43,208.
6.Ｆ・Sugimoto，YMaeda，ａｎｄＴ・Azumi,ﾉVippo〃ＫｎｊＭ ＧａＡｋｑｊｓｈｊ,1990,郷,１２４
７．RSugimoto,NTsunekage,andYMaeda,Ｍ〃o"肋gak〃
Ｋｍｓｈｊ,１９９２，６６７．
８．FSugimoto，Ｋ・Yoshikawa，ａｎｄＹ・Maeda，Ｃ/zemjstひ Exp”ss,1991,6,467.
9.Ｗ.。i,Ｊ・ＣａＯ，ＳＬｉｎ,SChen,andKSakai,Ｂ""Scハノ KZzgak",1991,伽,３９．
１０．s・Umemoto,MTakeo,Ｋ・Yoshikawa,Ｎ・Tsunekage,and YMaeda,Ｋα"ＡｙｏＧ的"肌1994,23,544.
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Ｈ・ＳａｔｏａｎｄＪ､Ueda,Ａ"αＬＳｃｊ.,2000,Ｊ6,1089．
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