Lanthanide Recognition: an Asymetric Erbium Microsensor Based on a Hydrazone Derivative

N'-(2-hydroxy-1,2-diphenylethylidene)benzohydrazide (HDB) was found tohave a very selective and sensitive behavior towards erbium(III) ions, in comparison tothirteen lanthanide ions, inner transition and representative metal ions and was hence usedas a neutral ion carrier in construction of an Er(III) microelectrode. Theoretical calculationsand conductance studies of HDB to erbium and some other metal ions were carried out andconfirmed selectivity toward Er(III) ions.The best performance was obtained with a membrane contain 3% potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as an anionic additive, 72% dibutyl phthalate (DBP) assolvent mediator, 5% HDB, and 20% poly(vinyl chloride) (PVC). The proposed Er(III)microelectrode exhibits a near Nernstian response of 17.5±0.5 mV per decade of erbiumactivity, and a very wide linear range 1.0×10-3-3.0×10-10 M. It can work well in the pHrange of 3.0-9.0. The lower detection limit (LDL) of the microelectrode was calculated tobe 2.0×10-10 M.