Adsorptive stripping voltammetric determination of antimony.

A new method is described for the determination of antimony based on the cathodic adsorptive stripping of Sb(III) complexed with 2',3,4',5,7-pentahydroxyflavone(morin) at a static mercury drop electrode (SMDE). The reduction current of the adsorbed antimony complex was measured by 1.5th-order derivative linear-sweep adsorption voltammetry. The peak potential is at -0.51 V (vs. SCE). The effects of various parameters on the response are discussed. The optimized analytical conditions were found to be: supporting electrolyte, chloroacetic acid (0.04 mol/l, pH 2.3); concentration of morin, 5x10(-6) mol/l; accumulation potential, -0.25 V (vs. SCE); scan rate, 100 mV/s. The limit of detection and the linear range were 7x10(-10) mol/l and 1.0x10(-9) approximately 3.0x10(-7) mol/l Sb(III) for a 2-min accumulation time, respectively. This method has been applied to the determination of Sb(III) in steel and brass samples and satisfactory results were obtained. The adsorptive voltammetric characteristics and composition of the Sb(III)-morin complex were studied.