Procaine as a sensing material for determination of Dysprosium(III) ions in presence of other rare-earth elements in biological and environmental samples

The biological properties of the lanthanides, primarily based on their similarity to calcium, have been the basis for research into potential therapeutic applications of lanthanides since the early part of the twentieth century. In this research, procaine was used as a sensing material in construction of a new Dy( III) potentiometric membrane sensor. The sensor exhibits a Nernstian response over a concentration range of 1.0 x 10(-6) mol l(-1) -1.0 x 10(-1) mol l(-1), with a detection limit of 7.9 x 10(-7) mol L-1. The best performance was achieved with a membrane composition, consisting of 30% PVC, 63% dibutylphthalate (DBP), 5% procaine and 2% sodium tetraphenylborate (NaTPB). It was found that at the pH range of 4.0 - 8.0, the potential response of the sensor was not affected by the pH. Furthermore, the lectrode presents satisfactory reproducibility, very fast response time (< 10 s) and relatively good discriminating ability for Dy(III) ions with respect to many common cations and other lanthanide ions. The sensor has been applied to the determination of Dy(III) in human serum and in soil and sediment samples. Validation with Certified Reference Material (CRM) was also done.