Determination of impurities in cadmium sulfide by inductively coupled plasma atomic emission spectroscopy

Magnesium, iron, copper, manganese and zinc are determined in solutions of CdS directly nebulized in ICP. The impurities content at 10-1 ppm level are determined by matrix-matched standards. The sample of CdS is dissolved in concentrated hydrochloric acid and the solutions evaporated to a white residue. Concentrated nitric acid and distilled water are used to dissolve the residue. Calibration curves are built by means of 1% solutions of pure CdS spired with the analytes. Background corrections are performed depending on the matrix influence. The detection limits of the impurities obtained by this method are: Fe, Cu, Mn, Zn - 10 ppm; Mg - 1 ppm. The relative standard deviation for determined concentrations of the analytes are: Mn - 2%; Cu and Fe - 7 - 8%; Mn and Zn - 14%. (author)