ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Sulfonephthalein dyes. IV. Methylxylenol blue as a metallochromic indicator for chelatometric microtitrations of rare earth metals

K. Vytřas, M. Malcová, and S. Kotrlý

Department of Analytical Chemistry, Institute of Chemical Technology, 532 10 Pardubice

Abstract:  The possibility of using methylxylenol blue as a metallochromic indicator for the chelatometric determination of Sc³⁺, La^{3 +} , Ce³⁺, Sm³⁺, and Er^{3 +} ions was examined by the method of photometric and visual comparison microtitration. The influence of the kind of buffer solution and of pH upon the steepness of the colour changes of methylxylenol blue was investigated. Lanthanum, samarium, and erbium can be titrated in the medium of urotropine or acetate buffer solutions, while for the titration of cerium(III) ions the acetate buffer solutions are better suited. Scandium is to be titrated in the medium of dilute nitric acid (pH 2 — 3) or formate buffer solutions. It is also possible to use methylxylenol blue for consecutive determination of scandium and lanthanoide in a mixture.

Full paper in Portable Document Format: 295a599.pdf

Chemical Papers 29 (5) 599–605 (1975)