Preparation of Cobalt Rapid Detection Powder and Its Application in On-Site Water Quality Analysis

Based on the color reaction of Co(Ⅱ) with 1-(2-pyridylazo)-2-naphthol, the cobalt detection powder I and II were prepared for rapid on-site determination of cobalt in water. Cobalt detection powder I was firstly added into the water sample, after reaction for 5 minutes, cobalt detection powder II was added. After reaction for 10 minutes, the absorbance of the solution at 585 nm was measured. Linear relationship was found between the absorbance and the mass concentration of Co(Ⅱ) in the range of 0.05-0.70 mg·L-1, with the detection limit (3σ) of 0.02 mg·L-1. The determination results of waste water samples were in consistent with those obtained by ICP-AES. RSDs (n=7) were less than 5.0% and recovery rates obtained by standard addition method were in the range of 108%-109%.