1. .~~I...,.. ~,~: ",fAvailableonlineat WW$clencedlrect.com.",!f '....;,;:;JrJ;~';;;:J;'~:c;..;;'..:':'c'~";'rt;,c;:;~{ c;. C"-!;'c'!,"0'"ic.C "1;1""c..-"""r.c'p"" "','-"MICROCHE,\lICAL..,', ",I'c,,;:, -C"cc :",:"""",,"',';",;ifc,:;"":"'-,!i,;"",;,,,;O:ci:;';'F;'1!~,,;':c',,,,,'". c,".~#;.~fl".;;o!.~J""...1.,..r.-'SClenceQlrect,,*",cC t;;,"";~.iJ".,it"J:'"'..,.-,Y;-'"cc"c,' ~{icrocheniical JoUnl31 Detem1inationof ultra trace amounts of cobalt and nickel in water samples by i~ductivel: -cQ\!pled plasma-optical "emissipn spectrometry afterc., ;precDncentrationon modifiedCIs-silicaextraction disks ", J:-. I "-,'.; Afshin Rajabi Khprrami *, rahereh Hashempur, Ali Mahmoudi, A'li Reza Karimi c-",.. " ;'[;~.!:.:~'eni~fC1~Jni~IJ=-:Fu...utyofScil!lI,,'es./s!iJmi,,"Azad(jnil'~rsity.K.:r,1jBr.JI:':::'Tehran,/~iJn.,-'c." ~~~~iv"d :'.O..:3nuaf)'2006; receive~in {~'~:d rom, 17 April 2006: acc"pt"d:- April 201}6 f..,i:", I I" A highly scnsiti';;: and P,ClIr3t.: mcthod,for preconccntration anc dctcnnination of ultra trace al::...,un15 cobalt and nickel jOtS in "\V3!erof sampl.:s is proposed. The rr~ct'ncenir3tion is achieved using Cis-silica extraction\disks modified \\;th 5-(6-methoxy-2-benzothi:lZol~:lZo)-8- aminoquinoline (MBTAQ).The r;:tained icnson the prepared solid ph3sewas eluted with 10 ml of 0.01 ~{nitric acid and measuredby inductively coupled pl3sma-optical emiss:on spectrometIy (ICP-OES). The influel:ce of the type and amount of eluent used,pH. sample and eluent fIo\v rat~s, amount of MBTAQ 3:1dth.: eff.:;:t of oth.:r ions on extraction efliciet:cy were investigated. The limit$ of detection of the method \\ere O.OSand 0.06 /lg I-I for cobalt and r:icke:. r.:spectively. and provide an enric}-..":1entfactor of 100. The results o1:-tain.:d 10 successive extraction.5onar:d elution'cycles revea!ed relat:ve s::tndard d.:\iations of 1.5 and 1.0~.. for cobalt and nickel. respectively. Tne proposed method has b.:enapplied to the detennination of ultra tr3;:e :lI11ounts cobalt and nickel ion$ in n3tural and synthetic water samp;':$ with sati:;factory results.~f !'{':2006 Elscvicr B.\: All rights rcs~r\.ed., K \I'nrd.~:Cobalt;~ici;el: Prec"l:ce~D":Iti()n;In.:uctivelycoupledplasma-orti.a!emission~cctrometry";,ccf.....j... 1. IntroductionCprocess control and medicine. Thc detennination oftracc an10unts of cobalt in naturdl waters is of great interest bccausc cobalt is Nickel can be found in m:lny environments and has beenimportant for living species as complexed Vitamin B1~. The shl)\vn to be essenti:ll for th;: h~man body. It is generally accepteddeficiency of cobalt in nllnin:111tsusually results in diff~rent t)pes that nickel concentr.1tions belo\\' the 0:1 ~tg ml-1 level in natur:l!ofal1emia. Tox.icological e.i~cts of large amounts of cobalt include \vaters are hannle55 t..)aquatic..'rganism5 and in'igated plants [I].vasodilation, flushing and '::lI'diomyopathy in humans ar:d anim;115. However, it has be~:1 clas5ifi~j as one of the 13 priority metalInvestigations have been ex:~nded to th~ bioche:ni5try of cobJlt 01 pollutants by us ErA for lIS \videspreJd use [2]. It is th~ meta!animals, microorganisms 3."1denzymes [5]. The maximum re- component of the e;:.o!)me ure35~ and 3Ssuch is considered to beconunended concentrdtion "[toxic ions such as nickel :111dcobalt in e~~entialto plants and sume 'domestic animals.Th~ essentiality ofdrinking water fur livestock is: Co-l.0mg I-I al1dNi-2.5 mg nickel to mal1has n..'t bccn d~m,,"nstrated. ;\-Iorc attention has b.:eI)1-;1[6]. For dril1king water for humal1 consum~'tion tI1Cupper limits focused on the toxicity of nickel in low concentrations. such a$th.:arc even Ics$. It is therefori: clear that a rcliablc analvtical mi:th..'d tact that nickell:al1..':lUSCali;:r~i..: rcactions and that certain ni.:kclmust bc cstablished to test \\'3ters and soil$ on a re~lar basis. ""' P"..,:,.-I".~" ~, \\.1L~.., ))~.~,)?~...L; cl.mt'()U,1d :. ma).\._"",~:",,,,'~.:.f~' L', ""c'.":"'.'-t-J'".~~,o"':>'J' Lr:J~~cI"-:.;":_;',,1 1":.1'L,,;1,""":':,,.""""'" ~"".r';' Cobalt is knO\\l1 to be essential at trace levels to man, anin1:11sanalyzed using flame atomic absorption techniques, which al- and plants for met;lbolic processes [4]. It is clear that the deter-though almost interference fre~ were labor intensive owing to mination of the trace amounts of cobalt in biological and environ-their one element at a time analytical mode. At the present time. menial Stll11ples important in the fieldsis