title: Layer-by-layer self assembly of a water-soluble phthalocyanine on gold. Application to the electrochemical determination of hydrogen peroxide.
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.
authors: Department of Chemistry, Vijayanagara SriKrishnadevaraya University, Jnana Sagara Campus, Bellary, Karnataka, India. lokeshsk@gmail.com
authors: Lokesh S
authors: LS
authors: Koodlur
mesh_terms: D055664:Electrochemical Techniques / Q000191:economics / Q000379:methods*; D005618:Fresh Water / Q000032:analysis; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis*; D007211:Indoles / Q000737:chemistry*; D057230:Limit of Detection; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D011095:Polyethylenes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; D014867:Water; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; C052738:cobalt tetrasulfophthalocyanine; D006046:Gold; D006861:Hydrogen Peroxide