Micelle mediated methodology for the determination of heavy metals in real samples by flame atomic absorption spectrometry

A simple and sensitive method is described for the pre-concentration by cloud point extraction followed by atomic absorption spectrometric determination of nickel, lead, zinc and copper ions in real samples. At a solution pH of 7.0, 2-amino-5-mercapto-l, 3,4 -thiadiazole (AMTD) and Triton X-114 were used as hydrophobic ligand and non-ionic surfactant. The adopted concentrations for AMTD, Triton X-114 and HNO3, bath temperature, centrifuge rate and time were optimized. Detection limits (3SDb/m) of 1.4, 1.6, 1.7 and 1.5 ng mL^-1 for Ni^2+, Pb^2+, Zn^2+ and Cu^2+ along with enrichment factors of 29 for these ions were achieved. The presented procedure was applied to the determination of analytes in cow liver, natural and industrial waste water and blood samples with successful results (recoveries greater than 97%, R.S.D., lower than 1.8 % for N= 3).