With the scientific and technological development,measurement for level of trace elements has been demanded to meet with the need of geological,biological,and environmental sample analysis.But the determination of these trace elements in the samples will often encounter difficulties and sometimes it is impossible,due to the sensitivity of analytical instruments and detection limit of analytical methods.Therefore we need the help of separation and enrichment technology to improve the analytical method sensitivity and selectivity.In the article,cloud point extraction was used for the preconcentration of metal element,cobalt,after the formation of a complex with PAN or PAR in the presence of surfactant TritonX-114,and then the mental element was determined by ultraviolet-visible absorption spectrometry.The conditions affecting the separation and detection process such as pH,the concentration of reagents and incubation time were optimized.The linear equation for determination of Co2+ was A=0.1848C(μg/50mL)+0.0229,and γ=0.9929.The detection limit(3s)for Co2+ was 0.02499(μg/50mL)and the linear range was 0.8～13(μg/50mL).This method showed the advantages of both cloud point extraction and ultraviolet-visible absorption spectrometry: high enrichment factor,simple operation,security,less sample,high accuracy and easy to realize the analysis.
