Trace Determination of Molybdenum by Adsorptive Cathodic Stripping Voltammetry
R. Hajiana and E. Shams b,*
aInstitute for Advanced Studies in Basic Sciences, Zanjan 45195-1159, Iran
bChemistry Department, Isfahan University, Isfahan, 81746-73441, Iran
(Received 1 May 2005, Accepted 15 October 2005)
Molybdenum is determined by adsorptive cathodic stripping voltammetry in 0.15 M nitric acid solution containing 15 µM 2’,3,4’,5,7-pentahydroxyflavone (morin) as a ligand. In this medium, molybdenum is preconcentrated on a hanging mercury drop electrode and stripped cathodically in square-wave voltammetry mode, with a peak potential of -350 mV vs. Ag/AgCl (saturated KCl). The effect of various parameters (ligand concentration, supporting electrolyte composition, accumulation potential and collection time) on the sensitivity and linear range of the calibration curve are discussed. With controlled accumulation for 1 min, the detection limit (3s) was 0.45 ng ml-1 molybdenum and the calibration curve is linear up to 70 ng ml-1. The procedure is applied to the determination of molybdenum in real samples with satisfactory results.
Keywords: Adsorptive stripping voltammetry, Molybdenum, Morin