A rapid method for the direct determination of copper and iron in butter by GFAAS

A rapid method for the direct determination of copper and iron in butter by GFAAS was developed. Butter was dissolved in a BuNH2/water/THF mixture in the ratio 0f 7.5% for copper and 2% for iron. The solution (10 mu L) was pi petted directly into the graphite tube. Two thermic programs were developed : for copper char-ashing at 900 degrees C, atomization at 2450 degrees C an d for iron, including deposition and drying of the chemical modifiers (Mg(N O3)(2)+ NH4NO3 0.1%, charashing at 1000 degrees C and atomization at 2400 d egrees C. The calibrations were compared with the matrix-matched standard a nd standard addition calibration. The accuracy was proved by comparison wit h the mineralization method. The direct determination against aqueous stand ards is possible with a characteristic mass of 6.5 pg/0.0044 A,s for copper and of 5.5 pg/0.0044 A.s for iron.