Simultaneous determination of cobalt and manganese in urine by electrothermal atomic absorption spectrometry. Method development using a simplex optimization approach

A rapid method for the simultaneous determination of Co and Mn in urine was developed using a multielemental Perkin-Elmer SIMAA 6000 graphite furnace atomic absorption spectrophotometer. A simplex optimization was used to establish the pyrolysis and atomization temperature, and the ramp and hold time for the pyrolysis step. The sample preparation was a simple 1+1 dilution, using a diluent of 2% v/v HNO sub(3) and 0.05% m/v Triton X-100 in MilliQ-water. The LODs were 0.18 mu g l super(-1) for Co and 0.09 mu g l super(-1) for Mn. The recovery studies, to check for bias, have shown acceptable accuracy for the procedure (104% for Co and 100% for Mn, with 15 and 13% RSD, respectively; 2 mu g l super(-1) Co added to 10 different samples at 0.46-1.91 mu g l super(-1), 2 mu g l super(-1) Mn added to 10 different samples at 0.11-1.09 mu g l super(-1)).