The Analysis Of Trace Mercury And Cadmium Based On Cloud Point Extraction Coupled To Inductively Plasma-mass Spectrometry

Water pollution is the major problem of all countries in the world concerned today.The heavy metal pollution receives greater attention due to its biological accumulation and toxicity.The heavy metals which have toxicity such as mercury,cadmium and other toxic metals' concentrations are in the range of 1-10 ?g/L which is so low and so complex that people have put forward higher requirements for the separation and preconcentration techniques in analytical chemistry.Cloud Point Extraction(short for CPE)is a new type of environment friendly technology whose development is rapid in recent years.It does not use toxic and volatile organic solvents which do less harm to the environment and laboratory personnel.It costs low and easy to use and easy to be applied in coupled to the instruments.This paper used the technology of CPE-ICP-MS to preconcentrate and detect trace Hg and Cd and applied to the detection of environmental water samples which obtained good effects of enrichment.The specific contents in the following were divided into four parts.1.The principle and steps of the cloud point extraction were summarized and the factors which affected the separation and extraction,the application of cloud point extraction and the combination of cloud point extraction were introduced.The research content and research significance were stated at last;2.This part used 1-(2-pyridylazo)-2-naphthol {PAN)for complexing and Triton X-114 for extracting and studied the factors which affected the cloud point extraction(such as the type and concentration of complexing agent,the concentration of surfactant,pH values,the concentration of buffer,the equilibrium temperature and equilibrium time,the centrifugal speed and centrifugal time,the icebath time,the interference of other metals and so on)and successfully established the method to use cloud point extraction to detect Hg in environmental water samples.The linear range of the method ranged from 1.0 ?g/L to 10.0 ?g/L,the correlation coefficient and detection limit of the method are 0.9998 and 0.025 ?g/L respectively.Under the optimized experimental conditions,RSD<1.0%,the recovery ranged from 98.0%to 103.0%;3.This part used 4-(2-thiazoleazo)-resorcinol(TAR)for complexing and Triton X-114 for extracting and studied the factors which affected the cloud point extraction and successfully established the method to use cloud point extraction to detect Cd in environmental water samples.The linear range of the method ranged from 1.0 ?g/L to 10.0 ?g/L,the correlation coefficient and detection limit of the method are 0.9999 and 0.023 ?g/L respectively.Under the optimized experimental conditions,RSD<1.4%,the recovery ranged from 95.0%to 102.0%;4.This part used ammonium pyrrolidinedithiocarbamate(APDC)for complexing and Triton X-114 for extracting and studied the factors which affected the cloud point extraction and successfully established the method to use cloud point extraction to detect Hg and Cd in environmental water samples.The linear range of the method ranged from 1.0 ?g/L to 10.0 ?g/L,the correlation coefficient of Hg and Cd are 0.9998 and 0.9999 respectively.The detection limit of Hg and Cd are 0.023?g/L and 0.022 ?g/L respectively.Under the optimized experimental conditions,RSD<1.3%,the recovery of Hg and Cd ranged from 96.5%to 106.0%and ranged from 96.0%to 105.0%respectively.