Preconcentration of Indium(III) from Complex Materials After Adsorption of Its Morpholine-4-dithiocarbamate on Naphthalene or Using Morpholine-4-dithiocarbamate-cetyltrimethylammonium Bromide-naphthalene Adsorbent

A highly selective, sensitive and rapid differential pulse polarographic method has been developed for the estimation of trace amounts of indium in standard alloy, ore, synthetic and environmental samples. The morpholine-4-dithiocarbamate of indium(III) is adsorbed on microcrystalline naphthalene in the pH range 3.5-6.4. The metal complex is desorbed with HCl and determined with a differential pulse polarograph (DPP). This metal may alternatively be quantitatively retained on morpholine-4-dithiocarbamate-cetyltrimethylammonium bromidenaphthalene adsorbent packed in a column at a flow rate of 0.5-5.0 ml/min and determined similarly. The detection limit is 0.10 ppm at the minimum instrumental setting (signal to noise ratio = 2). Indium has been determined in the 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 deviation of 0.89% (n = 8). Various parameters, such as the effect of pH, volume of aqueous phase, reagent, and naphthalene concentrations and interference of a large number of metal ions and anions on the estimation of indium have been studied in detail to optimize the conditions for its trace determination in various complex materials.