Abstract: Heavy rare earths can form a stable ternary complex with cetyltrimethylammonium bro-mide(CTMAB)and Ferron(7-iodo-8-hydroxyquinoline-5-sulfonic acid)in molar ratioof Y:Ferron:CTMAB=1:6:9 for yttrium. The maximum absorption wavelength of the Yternary complex was at 385nm at pH 3.2-3.8 of acetic acid-sodium acetate buffer.The apparent molar absorption coefficient was 1.5×10⁴ L·mol·cm^-1. The absorbance was linear tothe concentration of yttrium below 44μg/10mL. A method has been developed for the rapidand selective microdetermination of yttrium subgroup in mixed rare earths, using NaF asa masking agent.

Key words: Yttrium subgroup rare earth, spectrophotometry, ferron, quarternary ammonium bromide