ELECTROCATALYSIS AND FLOW DETECTION AT A GLASSY-CARBON ELECTRODE MODIFIED WITH A THIN-FILM OF OXYMANGANESE SPECIES

A modified electrode prepared by dipping a glassy carbon substrate into a 0.027 M MnCl2/1.4 M NaOH solution and cycling the potential between -0.5 and +0.4 V(vs. Ag/AgCl) greatly reduces the overvoltage for the oxidation of various hydrazines and hydrogen peroxide. The new electrocatalytic surfaces facilitate the amperometric detection of these compounds in flowing streams. Effects of pH, flow rate, operating potential, film thickness, concentration, and other variables on the catalytic response are explored. The electrode response is very stable. Detection limits at the femto- and picomole levels and relative standard deviations less than 1.3% are reported.