Trace Determination of Mo(VI) by Adsorptive Cathodic Stripping Voltammetry

Ravin Jugade^a and Arun P. Joshi^b
a Dept. of Chemistry, Jawaharlal Nehru College, Wadi, Nagpur-440023, India, E-mail: ravinj2001@yahoo.co.in
^b Dept. of Chemistry, Nagpur University, Nagpur-440033, India

Abstract
A rapid differential pulse adsorptive cathodic stripping voltammetric method has been developed for trace determination of Mo(VI) using alizarin red S as a complexing agent. The base electrolyte used is 0.01M acetate buffer at pH 4.0 at which a well defined peak is observed with Ep at –0.76 V. The optimum conditions for the analysis of molybdenum include 3.0 mM alizarin red S, accumulation potential of –0.4 V (versus Ag:AgCl), accumulation period of 60 s, rest period of 15 s, scan rate of 20 mV/s and pulse amplitude of 30 mV. The peak current is proportional to the concentration of molybdenum over the concentration range of 1–25 ppb with a detection limit of 0.25 ppb. The method has been applied to the determination of Mo(VI) in water samples.

Key words: Adsorptive, stripping, differential pulse, voltammetry, molybdenum