Determination of cobalt in animal feces by tungsten coil atomic absorptionspectrophotometry

An alternative analytical procedure for cobalt determination by tungsten co il electrothermal atomic absorption spectrophotometry (TCAAS) was developed to determine the liquid ruminal passage rate (turnover) of Co-EDTA in shee p feces. A matrix-matching procedure and a selective extraction of Co in 1. 0 mol l(-1) HCl were evaluated in order to correct and minimize the interfe rence effects caused by sample matrices. As application, six sheep received at the same time one dose of the marker (Co-EDTA); thier fecal samples wer e collected in intervals of 6 h during 90 h. The Co amounts determined in t he dry sheep feces by TCAAS were compared with those obtained by a flow inj ection catalytic spectrophotometric method. The characteristic mass and the detection limit, both based on peak height absorbance, were 23.1 and 19.1 pg, respectively, for 10 mi of sample volume in the samples of sheep feces. The rsd was 0.5% for 10 consecutive injections of 20.0 mg Co l(-1). The ac curacy was assessed by employing the paired t-test at 95% confidence level; there was no significant difference for Co content determined by TCAAS and by flow injection spectrophotometry.