title: Removal of copper and iron by polyurethane foam column in FIA system for the determination of nickel in pierced ring.
abstract: Polyurethane foam (PUF) mini-column was used to eliminate copper and iron for the determination of nickel in pierced rings. The PUF mini-column was connected to FIA system for on-line sorption of copper and iron in complexes form of CuSCN(+) and FeSCN(2+). For this season, the acid solution containing a mixture of Ni(II), Fe(III), Cu(II) and SCN(-) ions was firstly flew into the PUF column. Then, the percolated solution which Fe(III) and Cu(II) ions is separated from analysis was injected into FIA system to react with 4-(2-pyridylazo) resorcinol (PAR) reagent in basic condition which this method is called pH gradient technique. The Ni-PAR complexes obtained were measured theirs absorbance at 500 nm by UV visible spectrophotometer. In this study, it was found that Cu(II) and Fe(III) were completely to form complexes with 400 mmol/L KSCN and entirely to eliminate in acidic condition at pH 3.0. In the optimum condition of these experiments, the method provided the linear relationship between absorbance and the concentration of Ni(II) in the range from 5.00 to 30.00 mg/L. Linear equation is y=0.0134x+0.0033 (R(2)=0.9948). Precision, assessed in the term of the relative standard deviation, RSD, and accuracy for multiple determinations obtained in values of 0.77-1.73% and 97.4%, respectively. The level of an average amount of Ni(II) in six piercing rings was evaluated to be 14.78 mg/g.
authors.affiliation: Department of Chemistry, Faculty of Science, King Mongkut׳s University of Technology Thonburi, 126 Pracha-utid Road, Bangmod, Bangkok 10140, Thailand. Electronic address: sumalee.tan@kmutt.ac.th.
authors.forename: Monnapat
authors.initials: M
authors.lastname: Vongboot
authors.affiliation: Department of Chemistry, Faculty of Science, King Mongkut׳s University of Technology Thonburi, 126 Pracha-utid Road, Bangmod, Bangkok 10140, Thailand.
authors.forename: Monrudee
authors.initials: M
authors.lastname: Suesoonthon
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D017022:Flow Injection Analysis / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D055498:Jewelry / Q000032:analysis*; D009532:Nickel / Q000032:analysis*; D011140:Polyurethanes / Q000737:chemistry*; D013054:Spectrophotometry, Atomic
chemical_list: D002614:Chelating Agents; D011140:Polyurethanes; D003300:Copper; D009532:Nickel; C028279:polyurethane foam; D007501:Iron
keywords: FIA system; Nickel determination; Pierced rings; Polyurethane foam column