ELECTROCATALYSIS OF ANODIC OXYGEN-TRANSFER REACTIONS - ALIPHATIC-AMINES AT MIXED SILVER-LEAD OXIDE-FILM ELECTRODES

Results are described from research directed to the discovery of new a node materials suitable for obtaining stable and sensitive response wh en applied at constant potential for the amperometric detection of org anic amines. Voltammetric and amperometric results are compared for de tection of selected organic amines in carbonate buffer (pH 10) at,mixe d silver-lead oxide films prepared by electrodeposition on platinum su bstrates and by anodization of Ag-Pb alloys. Anodic response is observ ed at both electrodes for ethylamine, N-ethylmethylamine, trimethylami ne, ethanolamine, and L-alanine. However, data indicate that the oxide electrode formed by anodization of Ag-Pb alloys is superior with rega rd to stability of response. On the basis of flow-injection detection using constant applied potential in carbonate buffer, linear dynamic r anges (r(2) > 0.99) are at least three decades for selected primary se condary, tertiary, alkanolamine, and amino acids in carbonate buffer ( pH 10), with detection limits (S/N = 3) of ca. 0.3 mu M (i.e., 6 pmol per 20 mu l injection). Results are presented for the characterization of these films using x-ray diffractometry, x-ray photoelectron spectr oscopy, and scanning electron microscopy.