Determination of trace metals with solid phase extraction in environmental and traditional wheat flour samples

In this study, a new method is proposed for simultaneous determination of the pre-concentrated and separated of Cu(II), Ni(II) and Co(II) trace metal ions from wheat flour sample before UV-VIS spectrophotometric determination using Amberlite XAD-1180N resin and DMMDTC (2,6-dimethlmorpholinedithiocarbamate) ligand. For the method developed in standart model solution medium, the effects of some SPE parameters such as pH of the sample, reagent amount, eluent type, concentration and volume, sample and eluent flow rate, sample volume on the recovery (R%) of trace metal ions were investigated. Cu(II), Ni(II) and Co(II) trace metal ions retained on the Amberlite XAD-1180N as DMMDTC complexes were eluted with 10 mL of 1 M HNO3 (in acetone). The influences of foreign ions such as F-, Cl-, NO 3, CO3 2-, SO4 2-, I-, PO4 3-, Ca2+, Mg2+,Na+, Co2+, Cu2+, Zn2+, Pb2+, Fe3+ and K+ matrix ions in different concentrations on the recovery of trace metal ions were also examined individually by using the developed method. Cu(II), Ni(II) and Co(II) ions which were preconcentrated and separated from the sample by using the devoloped SPE method and their concentrations were determined simultaneously with the UV-Vis spectrophotometric method. The spectrophotometric determination was made by the measurements of the absorbance of colored chelates of metal ions complexed with DMMDTC in a surfactant medium (1% Triton X-100) at 460, 328 and 342 nm wavelengths for Cu(II), Ni(II) and Co(II) ions, respectively. For the accuracy of the method, certified reference materials (TMDA-70.2 Ontario lake water and CRM 1204 waste water) was analyzed with proposed method and the recoveries of metals were calculated between 97,1 and 100,7%. The proposed method was successfully applied to the wheat flour samples. KEYWORDS: Solid-phase extraction, Heavy metal ions, Amberlite XAD-1180N, 2,6-dimetilmorpholinedithiocarbamate, Wheat flour, UV-Vis spectrophotometer