Determination of Co(II) in water and soil samples using spectrophotometry coupled with preconcentration on 4-amino methyl pyridine anchored silica gel column.

4-amino methyl pyridine anchored silica gel (4-AMPS) was used as a sorbent in a simple sensitive spectrophotometry determination of Co(II) in various samples using piperazine dithiocarbamate as a color developing agent (lambda(max)=390 nm) at pH 5.0+/-0.2. Beer's law was obeyed over the range of 0.1-5.0 microg ml(-1). The molar absorptivity and Sandell's sensitivity were 1.257x10(5) lmol(-1) cm(-1) and 0.006145 microg cm(-2), respectively. Under these conditions, the preconcentration factor obtained was 80, and the detection limit achieved was 5.0 ng ml(-1). The detailed study of various interfering ions made the method more sensitive and selective. The recovery of Co(II) from various samples range from 97.50 to 99.66%. The present method was successfully applied for the determination of Co(II) in various water and soil samples. The proposed method was compared with reported methods in terms of Student's 't'-test and variance ratio 'f'-test which indicates that there is no significant difference between proposed and literature method at 95% confidence level.