STUDY OF ISOTACHOPHORETIC SEPARATION BEHAVIOR OF METAL-CATIONS BY MEANS OF PARTICLE-INDUCED X-RAY-EMISSION .3. ANALYSIS OF A CRUDE RARE-EARTH CHLORIDE FROM MONAZITE

A crude rare earth chloride produced from monazite was analysed by coupled isotachophoresis-particle-induced X-ray emission (ITP-PIXE). The sample was separated and fractionated by the use of a micro-preparative isotachophoretic analyser and the dropwise fractions containing nanomole amounts of rare earth elements were analysed off-line by PIXE. By means of ITP-PIXE, the minor elements (Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) co-existing with the other major lanthanoids (La, Ce, Pr and Nd) were determined accurately, because the "matrix effect" in X-ray analysis was reduced by isotachophoretic removal of the major elements. The maximum abundance found was for Ce at 47.4% with respect to total rare earths and the minimum abundance was 0.001% for Lu. The separation efficiency of the crude rare earth chloride was ca. 500 nmol/C. The method for the fractionation of minor elements and PIXE analysis is discussed in detail. The analytical results obtained by ITP-PIXE were confirmed by means of inductively coupled plasma atomic emission spectrometry.