ELECTROCATALYSIS AND AMPEROMETRIC DETECTION OF ALIPHATIC-ALDEHYDES ATPLATINUM-PALLADIUM ALLOY COATED GLASSY-CARBON ELECTRODE

Aliphatic aldehydes undergo an electrocatalytic oxidation at a platinu m-palladium (Pt-Pd) alloy coated glassy carbon electrode. The alloy mo dification offers a highly sensitive and stable, constant (+0.35 V) po tential detection of simple aldehydes. The drastically enhanced cataly tic response of the alloy deposit, compared to the single component me tals, is attributed to synergistic effect associated with changes in t he adsorption features of the surface. The influence of the alloy depo sition conditions upon the amperometric response is assessed. Scanning electron microscopy, energy dispersive X-ray analysis and elemental d istribution mapping offer useful insights into the microstructure and composition of the alloy deposit. Formaldehyde, acetaldehyde and propi onaldehyde were detected in flow-injection analysis at levels as low a s 0.9, 6.4 and 6.5 ng (30, 160 and 120 pmol), respectively. Such opera tion offers lower operating potentials and detection limits compared t o the recently developed mixed-valent ruthenium coated detector for al dehydes [2].