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  • Layer-by-layer self assembly of a water-soluble phthalocyanine on gold. Application to the electrochemical determination of hydrogen peroxide.

Layer-by-layer self assembly of a water-soluble phthalocyanine on gold. Application to the electrochemical determination of hydrogen peroxide.

Bioelectrochemistry (Amsterdam, Netherlands) (2013-01-22)
Lokesh S Koodlur
ABSTRACT

A self-assembled molecular film of a water-soluble cobalt tetrasulfophthalocyanine was deposited on a gold substrate premodified with poly(diallyldimethylammonium chloride). The process of layer-by-layer assembly on the gold substrate was characterized using UV-Vis, Raman spectroscopy, ellipsometry, contact angle measurements, atomic force microscopy and electrochemical methods. Results demonstrate the formation of a completely covered phthalocyanine film on the gold surface. UV-Vis spectra indicated the formation of monolayer film of the phthalocyanine on the surface. The functionalized surface is uniformly covered and becomes hydrophilic after modification. The modified gold surface exhibits a reversible redox behavior and acts as an electronic conductor for the electrochemical reduction of hydrogen peroxide in pH 7.0 phosphate buffer. A linear increase in the catalytic current is observed for the reduction of hydrogen peroxide in the concentration range from 1 to 20 μM, with a detection limit of 0.4 μM. Hydrogen peroxide spiked pond water sample showed a recovery of 94% indicating the method is selective and can be applied for various applications. The present method is a simple, cost effective and sensitive electrochemical method for the detection and quantification of hydrogen peroxide.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Poly(diallyldimethylammonium chloride) solution, average Mw 400,000-500,000 (high molecular weight), 20 wt. % in H2O
Sigma-Aldrich
Poly(diallyldimethylammonium chloride) solution, average Mw 200,000-350,000 (medium molecular weight), 20 wt. % in H2O
Sigma-Aldrich
Poly(diallyldimethylammonium chloride) solution, 20 wt. % in H2O
Sigma-Aldrich
Poly(diallyldimethylammonium chloride) solution, average Mw <100,000 (very low molecular weight), 35 wt. % in H2O