Determination of ultratrace amounts of cobalt by catalysis of the tiron-hydrogen peroxide reaction with an improved continuous-flow analysis system

An improved continuous-flow analysis method has been designed and applied to the determination of ultratrace amounts of cobalt(II) by the catalysis of the tiron-hydrogen peroxide reaction in basic medium. From 3 to 5000 pg of cobalt(II) in 1 ml of acidified sample can be determined at a sampling rate of 40 samples/hour. The relative standard deviations (10 replicates) are 1% at the 100 pg/ml level and 3% at 10 pg/ml.