Study on determination of trace cobalt in natural water by thin layer resin phase spectrophotometry

A quaternion association complex system which was formed by HDMG,iodide,Co(Ⅱ) and 717 strong alkalious anion exchange resin,has the largest absorbance at the wavelength of 454 nm.With the quaternion association complex system,the sensitivity was 14 times higher uhan that of the ternary association complex of HDMG,iodide and Co(Ⅱ) in water solution,based on the increase of the complex molecular sectional area and the pelectron free space of the Co complex in the resin phase.This increase also changed the largest absorbance wavelength from 442 nm(in water solution) to 454 nm(in resin phase).The RSD of the method was 1.3%(n=6) for 2.0 μg/mL.The deve-loped method was applied to the determination of trace Cobalt in surface water,the linear range of 0.024～2.0 μg/mL and detection limited of 10.4 ng/mL was achieved.