PRECONCENTRATION OF INDIUM(III) FROM COMPLEX MATERIALS AFTER ADSORPTION OF ITS MORPHOLINE-4-DITHIOCARBAMATE ON NAPHTHALENE OR USING ORPHOLINE-4-DITHIOCARBAMATE-CETYLTRIMETHYLAMMONIUM BROMIDE-NAPHTHALENE ADSORBENT

A highly selective, sensitive and rapid differential pulse polarograph ic method has been developed for the estimation of trace amounts of in dium in standard alloy, ore, synthetic and environmental samples. The morpholine-4-dithiocarbamate of indium(III) is adsorbed on microcrysta lline naphthalene in the pH range 3.5-6.4. The metal complex is desorb ed with HCl and determined with a differential pulse polarograph (DPP) . This metal may alternatively be quantitatively retained on orpholine -4-dithiocarbamate-cetyltrimethylammonium bromide-naphthalene adsorben t packed in a column at a flow rate of 0.5-5.0 ml/min and determined s imilarly. The detection limit is 0.10 ppm at the minimum instrumental setting (signal to noise ratio = 2). Indium has been. determined in th e concentration, range 0.70 - 15.0 ppm with a correlation factor of 0. 9996 and a relative standard deviation of 0.76% (n = 8). In the column method, the linearity is maintained in the concentration range 0.70 - 8.5 ppm with a correlation factor of 0.9994 and a relative standard d eviation of 0.89% (n = 8). Various parameters, such as the effect of p H, volume of aqueous phase, reagent, and naphthalene concentrations an d interference of a large number of metal ions and anions on the estim ation of indium have been studied in detail to optimize the conditions for its trace determination in Various complex materials.