Multielemental Analysis of Tellurium Dioxide with Sample Matrix Preseparation by Reactive Distillation

A method is proposed for matrix separation from a sample of tellurium dioxide TeO₂ as tellurium tetrachloride based on reactive distillation in a flow reactor at 240°C using gaseous chlorine as a chlorination agent. The behavior of 59 impurities is studied, and it was found that As, Au, B, Bi, Cu, Ga, In, Mo, Nb, Pb, Re, Ru, Sb, Se, Sn, Ta, Ti, V, W, and Zn were lost completely or partially, whereas Ag, Al, Ba, Be, Ca, Cd, Ce, Co, Cr, Dy, Er, Eu, Gd, Ir, Hf, Ho, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, P, Pd, Pr, Pt, Rb, Rh, Sc, Sm, Sr, Tb, Tm, Y, Yb, and Zr were retained in the concentrate by more than 75%. The impurity content of the concentrate was determined by inductively coupled plasma atomic emission spectrometry. Accuracy was confirmed by the spike experiment and by comparison with the results of analyses without preconcentration. The limits of detection are in the range from 2 × 10^–8 to 8 × 10^–6 wt %, intralaboratory precision is better than 31%.