ATOMIC ABSORPTION CHARACTERISTICS OF GALLIUM AND INDIUM

The atomic absorption characteristics of Ga and In were studied using a demountable hollow cathode and a Jarrell-Ash 0.5 m grating spectrometer. Gallium was most sensitive in a fuel-lean premixed C2H2/N2O flame at a position in the flame immediately above the burner head. At the 2943.64-2944.18 Å unresolved doublet, the detection limit of Ga was 0.3 ppm in aqueous solution. Indium was most sensitive in a fuel-lean premixed C2H2/air flame at a position of 0.2-0.3 cm above the burner head. When the 3256.09 Å line was used, the detection limit for In was 0.3 ppm in aqueous solution. Studies of various extraneous ions at concentrations from 100 to 1500 ppm indicated very few interferences with 100 ppm Ga or In. In the nitrous oxide flame only Bi and Ni caused severe Ga absorbance depression, while Na, K, and PO43- ions caused some absorbance enhancement. In the air-acetylene flame only Ni caused severe depression of In absorbance, while V, Ca, and Mg caused only slight absorbance depression. © 1969.