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

Spectrophotometric determination of lanthanoides and yttrium by flow-injection analysis, using Chrome Azurol S in the presence of cationic surfactants

D.B. Gladilovič and V. Kubáň

University, Department of Analytical Chemistry, A. A. Zhdanov SU-199164 Leningrad

Abstract: In alkaline 0.1 M solution of ammonia buffer, having a pH of 9.4±0.2, and containing hexadecyltrimethylammonium bromide (CTMAB) (с = 0.1 —0.2 mmol dm^-3 ) or hexadecylpyridinium bromide (СРВ) (с = 0.2—0.4 mmol dm^-3 ), Chrome Azurol S forms stable products with rare earth and yttrium ions. These products have an absorption maximum at λ=620 nm and molar absorption coefficients ε=6.3—7.1 m² mmol¹ for CTM AB and  ε= 6.8—8.2 m² mmol^-1 for СРВ. In the presence of CTM AB (с = 0.10—0.15 mmol dm³ ) and at pH % 10 a less stable product is formed, with an absorption maximum at   λ= 650 nm and s = 9.2 m² mmol^-1 Poorly selective reactions of lanthanoides and yttrium possess high sensitivity with a detection limit DL = 0.3-0.6 μmoldm3 for СРВ and DL = 0.5—0.9 μmol dm^-3 for CTM AB, respectively, and with high colour contrast  Δλ= 200—230 nm. Optimal conditions for analysis depend on the reagent and surfactant concentration and to some extent on the concentration of lanthanoide and of the inert salt as well. The reaction has been utilized for the determination of Ln(III) and Y(III) by means of flow injection analysis at  λ=620 nm or 650 nm in the concentration range of 2—20  μmol dm³ of Ln(III), DL = 2—3 μmol dm^-3 of Ln(III). The determination was preceded by the separation of lanthanoides. The reaction can also be applied for postcolumn derivatization of lanthanoides after HPLC or IEC separation chromatography.

Full paper in Portable Document Format: 425a607.pdf

Chemical Papers 42 (5) 607–620 (1988)