A ternary complex is formed when 7-(1'-naphthylamine-azo)-8-hydroxyquinolin
e-5-sulfonic acid (NAOX) occupied the two remaining coordination sites on a
lanthanide ion complexed by a hexadentate aminopolycarboxylate ligand. The
effects on the fluorescence intensity are studied. The NAOX/EDTA reagent s
ystem provides sensitive and selective determination of Lu3+ and Y3+, with
the detection limits of 5.0 x 10(-7) and 7.0 x 10(-7) mol/l, respectively.
In addition, the ternary complex can be used for determination of EDTA or o
ther hexadentate aminopolycarboxylic acids. (C) 1999 Elsevier Science B.V.
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