摘要
The variety of newly synthesized diamides of dipicolinic acid(DPA)bearing methyl-and oxymethyl substituents in various positions of phenyl ring was investigated as potential ligands for liquid-liquid extraction of rare earth metal ions and as membrane active compounds in plasticized polymeric membranes of potentiometric sensors.It is found that scandium is extracted with 2,6-pyridinedicarboxylic acid diamides similarly to heavy lanthanides,while yttrium is extracted together with light group lanthanides.DPA shows high selectivity for the separation of cadmium/zinc,lead/nickel or copper/nickel pairs.The four out of six studied ligands demonstrate significant potentiometric sensitivity towards scandium,yttrium and lanthanides in 10^(-7)-10^(-3)mol/L concentration range in nitric acid solutions.The trends in sensitivity values vary depending on a ligand structure and the highest values are observed for Sc^(3+)and heavy lanthanides.According to the evaluated selectivity Sm^(3+)is the most preferred ion,while La^(3+)is the most discriminated.The differences in sensor behavior in rare earth metal solutions assume that such devices can be applied in sensor arrays for potentiometric analysis of lanthanide mixtures.
