TITLE:
Square-Wave Adsorptive Cathodic Stripping Voltammeteric Determination of Manganese (II) Using a Carbon Paste Electrode Modified with Montmorillonite Clay
AUTHORS:
Amr M. Beltagi, Iqbal M. Ismail, Mohamed M. Ghoneim
KEYWORDS:
Manganese; Stripping Voltammetry; Carbon Paste Electrode; Montmorillonite Clay
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.4 No.4,
April
29,
2013
ABSTRACT:
Manganese is an essential micronutrient for all
organisms; however at high concentrations it has a toxic effect.
Manganese toxicity is a serious constraint to crop cultivation since it
is taken-up by plants and can easily be passed into the food chain again
causing symptoms of Parkinson’s disease. A fully validated square-wave
adsorptive cathodic stripping voltammetry method has been developed for
determination of Mn (II) as a complex with 2-(5’-bromo-2’-pyridylazo) 5-diethylaminophenol
in aqueous solutions using a carbon paste electrode (CPE) modified with
montmorillonite-Na clay. The results showed that the modified CPE (90% (w/w)
graphite powder and 10% (w/w) montmorillonite-Na clay) exhibited excellent
electrochemical activity towards the investigated Mn (II) complex in acetate
buffer of pH = 5.0. Factors affecting the performance of the modified carbon
paste electrode and the sensitivity of the described square- wave
stripping voltammetry method, including the electrode composition,
concentration of ligand, pulse parameters and preconcentration conditions were
examined. A detection limit (S/N = 3) of 0.015μg·L-1 (2.73 × 10-10 mol·L-1)
Mn (II) was achieved when a preconcentration time of 240 s was applied.
Insignificant interferences from various inorganic and organic species were
estimated. The described square-wave adsorptive cathodic stripping voltammetry
method coupled with the modified carbon paste electrode has been successfully
applied to Mn (II) analysis in different water samples.