02213naa a2200241 a 450000100080000000500110000800800410001910000180006024501960007826000090027452014170028365000110170065300200171165300270173165300410175865300160179965300180181570000210183370000260185470000210188070000200190177300500192110456692013-08-30       2006    bl uuuu     u00u1 u    #d1 aDONATI, G. L.  aAcid extraction and cloud point preconcentration as sample preparation strategies for cobalt determination in biological materials by thermospray flame furnace atomic absorption spectrometry.  c2006  aA thermospray flame furnace atomic absorption spectrometer (TS-FF-AAS) was employed for Co detennination in biological materiaIs. Cobalt presents a high atomization temperature and consequently poor sensitivity is obtained without changing its thennochemical behavior. The effect of different complexing agents on sensitivity was evaluated based on the fonnation of Co volatile compounds. A cloud point procedure was optimized for Co preconcentration for further improvement of sensitivity. Samples were treated with I moI I-I hydrochloric acid solution for quantitative extraction of Co without simultaneous extraction of Fe, since it is a strong interferent. After the extraction and preconcentration steps, a sample volume of 150 /lI was introduced into the hot Ni tube using air as carrier at a tlow-rate of 0.4 ml min- I. The best sensitivity was attained using ammonium pyrrolidinedithiocarbamate (APDC) and Triton X-114 was employed for implementation of the cloud point procedure. The detection limit obtained for Co was 2.1 /lg 1-1 and the standard deviation was 5.8% for a solution containing 100/lg I-I (n= 10). Accuracy was checked using two certified reference materiaIs (tomato leaves and bovine li ver) and results were in agreement with certified values at a 95% confidence leveI. Employing the developed procedure, Co were quantified in different biological materiaIs (plant and animal tissues).  acobalt  aAcid extraction  aCloud point extraction  aFlame atomic absorption spectrometry  aThermospray  aTube in flame1 aNASCENTES, C. C.1 aNOGUEIRA, A. R. de A.1 aARRUDA, M. A. Z.1 aNÓBREGA, J. A.  tMicrochemical Journalgv.82, p.189-195, 2006.