Determinação direta e simultânea de Al, As, Fe, Mn e Ni em cachaça por espectrometria de absorção atômica em forno de grafite

This work describes a simple and fast method for the direct and simultaneous determination of Al, As, Fe, Mn and Ni in cachaça by graphite furnace atomic absorption spectrometry (GFAAS). The upside of platform of the graphite tube was coated with a W-based film (W xCyOz). The optimized heating program (temperature, ramp time, hold time) involved the following heating cycle: drying 1 (100oC, 5 s, 5 s); drying 2 (120oC, 5 s, 5 s); pyrolysis (1300oC, 10 s, 30 s); atomization (2200oC, 1 s, 6 s) and cleaning (2550oC, 1s, 3 s). The relative standard deviations (n=3) were: < 4.4%, < 0.7%, < 11%, < 6%, < 1.2% for Al, As, Fe, Mn and Ni, respectively. The recoveries of Al, As, Fe, Mn and Ni added to cachaça samples varied from 80% to 105%, 81% to 92%, 82 to 106%, 83 to 106% and 83% to 108%, respectively. The limits of detection (LOD) were 9.7 µg l-1 Al, 2.3 µg l-1 As, 12 µg l-1 Fe, 14 µg l-1 Mn and 0.8 µg l-1 Ni.