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8250825 
Journal Article 
Preparation and application of a surface-active azo compound for fluorometric determination of trace gallium 
Kina, K; Hirokata, K; Ishibashi, N 
1977 
1 
Bunseki Kagaku / Analysis Chemistry
ISSN: 0525-1931 
26 
4 
246-252 
English 
Dodecyl-lumogallion (Dodecyl·LUMO) which possesses surface-active property has been synthesized by the coupling of diazotized 2-amino-4-chlorophenol-6-sulfonic acid with dodecylresorcinol. Dodecyl·LUMO formed an orange-colored chelate complex with gallium (III) in the pH range of 2.8 to 3.7. The results of the continuous variation method exhibited the one to one complex formation. The Ga(III)-Dodecyl·LUMO complex is practically nonfluorescent in an aqueous solution, but does strongly fluoresce in surfactant micellar systems. From the stability of the chelate complex in the presence of surfactant and the degree of enhancement of fluorescence, polyethylene glycol monolauryl ehter (PGME) was judged to be the useful surfactant for gallium analysis. The complex has its maximum emission at 578 nm with an excitation at 493 nm in PGME micellar system. The concentration of ppb level of gallium was able to be easily determined by the fluorescence enhancement effect. The fluorescence polarization spectra revealed that the presence of dodecyl group caused a strong binding of the complex to the micelle. The Ga(III)-Dodecyl·LUMO complex is easily extracted into methyl isobutyl ketone (MIBK). The MIBK extraction method makes it possible to carry out the selective determination of the trace gallium. The presence of twenty-fold amounts of aluminum did not interfere. All experiments on the effect of diverse ions were carried out 0.151 μg/ml of gallium. The results are summerized in Table 1. The ions, Ge(IV), Co(II), Ni(II), Pb(II), and In(III) did not interfere. The interference of Fe(III) ion can be reduced by the addition of ascorbic acid and Cu(II) ion can be completely masked with sodium thiosulfate. © 1977, The Japan Society for Analytical Chemistry. All rights reserved. 
Fluorometric determination; Gallium; Methyl isobutyl keton extraction; Micellar effect; Surface-active azo compound