DETERMINATION OF GALLIUM BY GRAPHITE-FURN ACE AAS UTILIZING DIRECT ONE-BEAD-OF-RESIN INSERTION TECHNIQUE AFTER RETENTION WITH TIRON ON UNIFORM ANION-EXCHANGE RESIN

Trace amounts of Ga were determined by graphite furnace AAS after anio n-exchange resin separation with Tiron utilizing the direct one-bead-o f-resin insertion technique. The analytical procedure is as follows; a 2-ml portion of sample solution containing less than 0.5 mu g Ga was transferred into a 15-ml stoppered transparent test tube and 0.5 mi of 1.0X10(-4) M. Tiron solution and 2 mi of buffer solution (pH 5.5) wer e added. After dilution with water to 5 mi, 10.0 mg of anion-exchange resin was added and the mixture was shaken vigorously for 30 min. The liquid phase was discarded through a filter paper (5A) and the resin w as washed three times with 5 mi of buffer solution diluted to ten time s. The resin was dried in a desiccator at room temperature and one bea d of the resin was set in a cup type cuvette, the absorbance was then measured. The working curve for Ga was linear over the range of 0.05 s imilar to 0.50 mu g. The relative standard deviation for five determin ations of 0.50 mu g Ga was 3.8%. The detection limit, defined as three times the standard deviation of the reagent blank, was 1.5 ng ml(-1). The tolerable amount of sulfate, nitrate and chloride ion increased t en-fold, one hundred-fold and one thousand-fold, respectively compared with the ordinary method by graphite furnace AAS. Al(III), Fe(III), I n(III), and Mo(VI) were found to interfere.