Trace analysis of aluminum in natural waters with rubeanic acid by adsorption chronopotentiometry

The determination of trace levels of aluminum in natural waters with rubeanic acid (RA) by adsorption chronopotentiometry is developed in this paper. Optimum experimental conditions include an accumulation potential of -0.40 V, accumulation time of 60 s, and a RA concentration of 6x10(-6) M in 0.2 M NaAc-HAc buffer solution (pH 4.6). The response is linear over the 1x10(-8) approximately 4x10(-7) M concentration range. The detection limit is 5.6x10(-9) M and the relative S.D. (at the 3x10(-7) M level) is 2.6%. Possible interferences are evaluated. The method has been applied to the determination of trace levels of Al in various real samples. Direct determination of toxic forms of Al in surface waters by this technique is also explored.