Determining structure of chelate complex of polyethyleneimine with cupric ion and its analysis application

A complexing process of PEI with cupric ion was studied by using spectrophotometric analysis and conductometric titration,and the structure of the chelate was determined.The experimental results show that the chelate with coordination number 4 is formed between polyethedeneimine and cupricion,the rate of coordination is fast,and the chelate is stable.During titration process of PEI aqueous solution against Cu~(2+) solution,the conductivity decreases rapidly,and breakover occurs at the end point of titration.Based on the fact,a novel measurement method for Cu~(2+) content has been found,that is conductometric titration by using PEI.The effects of various factors on the analysis method were examined,and the analysis conditions were optimized.This method has high sensibility and better selectivity,and also it is very convenient.