Adsorptive stripping voltammetric measurements of trace levels of uranium following chelation with mordant blue 9.

The chelate of uranium with the azo dye Mordant Blue 9 is shown to be adsorbed and then reduced on the hanging mercury drop electrode. These properties have been exploited in developing a highly sensitive stripping voltammetric procedure for trace determination of uranium. With controlled adsorptive accumulation for 5 min, a detection limit near 2 x 10(-10)M uranium is obtained. Cyclic voltammetry has been used to characterize the interfacial and redox behaviour. The effect of various operational parameters on the stripping response is discussed. Experimental conditions include use of 1 x 10(-6)M Mordant Blue 9 in 0.05M acetate buffer (pH 6.5), an accumulation potential of -0.43 V, and a linear potential scan. The response is linear up to 1.2 x 10(-7)M uranium, and the relative standard deviation at 4.2 x 10(-8)M is 3.2%. The effects of possible interferences from organic surfactants or metal ions have been investigated.