Highly Selective Nd(III) Sensors: Novel Macrocyclic Compounds for Potentiometric Determination of Neodymium

Abstract

Conductometric studies on the complexation properties of two newly synthesized lariat ethers viz 1,5-di(cyanoethane)-2,4 : 7,8 : 13,14-tribenzo-1,5-diaza-9,12-dioxacyclopentadeca-2,7,13-triene (L 1 ) and 1,5-di(cyanoethane)-2,3,4-pyridine-7,8 : 13,14-dibenzo-1,3,5-triaza-9,12-dioxa cyclopentadeca-2,7,13-triene (L 2 ) towards various metal ions in acetonitrile solutions revealed the formation of 1 : 1 ligand metal complexation. These compounds were explored as neutral ionophores for the fabrication of Nd 3þ selective and sensitive membrane coated graphite electrodes (CGEs). Among all the electrodes prepared, CGEs with membrane composition L 1 (5%) : NaTPB(3%) : NPOE (57%) : PVC (35%) and L 2 (5%) : NaTPB(3%) : NPOE (53%) : PVC (39%) showed best performance. Both the electrodes showed Nernstian response towards Nd 3þ ions over a wide concentration range with detection limits 3.8 Â 10 À8 mol L À1 and 1.6 Â 10 À8 mol L À1 respectively. These electrodes showed a fast response time of < 15 s and could be used over a period of three months without significant divergence in their characteristics. The proposed electrodes revealed very good selectivity for Nd 3þ ions over several ions. However, higher concentration of Co 2þ , La 3þ , Pr 3þ and Yb 3þ caused some interference. The potentiometric response of these electrodes was excellent in the range of pH 3.5 to 7.6 and they could tolerate up to 20% (v/v) nonaqueous media in the test solutions. These electrodes were used successfully as indicator electrode in the potentiometric titration of Nd 3þ against EDTA and also in the quantitative determination of Nd 3þ ions from binary mixtures and water samples.

Developing Sensing Materials for Multisensor Systems on the Basis of Extraction Data

“…and highly selective sensors for each particular lanthanide can hardly be developed. In spite of this, lanthanide selective potentiometric sensors were widely reported in recent literature [61][62][63][64][65]. These sensors are of questionable use for SNF analysis task since they typically have pH working range of 4-8, while the presence of Me 3+ species in solutions with pH 4 and higher is negligible.…”

Potentiometric Sensor Array for Analysis of Complex Rare Earth Mixtures

“…Potentiometric measurements with the multisensor array were performed twice in each of these mixtures. The results of the measurements in 21 mixtures (42 samples), namely mixtures ## 1, 3,5,6,8,10,11,13,15,16,18,20,23,25,27,28,30,32,35,37,39 were employed for constructing three separate PLS1 regression models for yttrium, lanthanum and gadolinium. Optimization of the model parameters was performed using full cross-validation.…”

“…lanthanum and cerium selective sensors were suggested in [8,9] (based on the same trithiane ligand). Ion selective sensors for neodymium [10,11], praseodymium [12], dysprosium [13], etc. are reported.…”