The Study On Analysis Of Cu,Mn And Co In Environmental Sample With Atomic Absorption Spectrometric After Cloud Point Extraction

With the advancement of science and technology,heavy metal pollution has become a serious problem that destroys the ecological environment and threatens human health.Therefore,the determination of heavy metal content has become a focus for many scholars.Because heavy metals have the characteristics of transferring easily and high toxicity,it is great significance to accurately determine the content of heavy metals in environmental samples.However,determinating heavy mental content in food and environmental samples is difficult to meet the requirements,which is required to reach a level as ng/L.The atomic absorption spectrometry with higher sensitivity is still unable to meet the standard.It is necessary to improve the sensitivity and detection limit of the instrument by means of separation and enrichment.Therefore,this thesis decided to use cloud point extraction.Cloud point extraction(CPE)is a liquid-liquid extraction technology that is friendly to environment.It utilizes the cloud point phenomenon of surfactants to separate the hydrophobe and hydrophil.And during the experiment,we need to change the temperature,pH,and ionic strength to lead the phase separation.Cloud point extraction has many advantages,such as high enrichment factor,handling simply and non-polluting green,which makes cloud point extraction has been aroused widely used in the field of environmental science and life science.Now it is combined with analytical instruments successfully to detect heavy metal ions.This paper adopted cloud point extraction combined with flame atomic absorption.Based on TritonX-114 as surfactant,Manganese,Copper and Cobalt have formed ternary complex with Calcon carboxylic acid(CCA)in the presence of Cetyl pyridinium chloride(CPC)or Cetyl pyridinium bromide(CPB)to detect Mn,Cu and Co in environmental samples.The experiments were performed from pH,the dosage of Triton X-114 and CCA,coexisting ions,the heating time,heating temperature,ionic strength,ionic surfactant,ice-bath time,diluent agent etc.And optimize the system according to linear range,precision and detection limit,etc.which proved the superiority of the method.This paper studied the following three systems for the determination of trace heavy metals by cloud point extraction.1.Mn-CCA-CPC cloud point extraction system to detect Mn in water samples.The linear range of the method was 0.3mg/L-1.5mg/L,the precision was 0.39%,and the detection limit was 0.39mg/L.2.Cu-CCA-CPB cloud point extraction system to detect Cu in tobacco samples.The linear range of the method was 0.2mg/L-2.0mg/L,the precision was 0.18%,and the detection limit was 0.38mg/L.3.Co-CCA-CPC cloud point extraction system to detect valid Co and total Co in the soil samples.The linear range of the method was 0.5mg/L-2.0mg/L,the precision was 1.63%,and the detection limit was 0.66mg/L.