J. Ishikawa et al., ACYCLIC AND CYCLIC POLYTHIAMONOAZA-ALKANE AND POLYTHIADIAZA-ALKANE HYDRAZONE DERIVATIVES AS CHROMOGENIC EXTRACTANTS FOR SILVER ION, Analyst, 123(2), 1998, pp. 201-207
Acyclic and cyclic dithiaza-, tetrathiaza- and tetrathiadiazaalkane de
rivatives bearing 6-trifluoromethyl-2,4-dinitrophenylhydrazono moietie
s as chromogenic groups on the nitrogen atoms of the alkanes were synt
hesized and used as extractants for some class ab and b metal ions in
liquid-liquid extraction, The extraction behavior was estimated by usi
ng the spectral change in the organic phase containing the chromoionop
hore, All of these compounds exhibited high Ag+ selectivity relative t
o other class ab and b metal ions, which are soft Lewis acids, even ag
ainst Hg2+. In the extraction of silver nitrate from aqueous acidic an
d basic phases, interestingly, the absorption maxima of the organic ph
ases containing the chromoionophores in the visible absorption region
shifted to shorter and longer wavelengths, respectively, Among the chr
omoionophores used here, the acyclic tetrathiazaalkane hydrazone 4b ex
tracted Ag+ most effectively from an aqueous phase into a 1,2-dichloro
ethane phase under all the extraction conditions studied, A linear cal
ibration graph up to 5.5 x 10(-5) mol dm(-3) Ag+ in the aqueous neutra
l phase was obtained spectrophotometrically by using the acyclic tetra
thiazaalkane hydrazone 4b and the determination of Ag+ in a silver sol
der sample was achieved from the calibration graph.