Electrocatalysis and flow detection of alcohols at ruthenium dioxide‐modified electrodes

Ruthenium dioxide‐(RuO₂)‐containing carbon paste electrodes exhibiting electrocatalytic responses toward alcohols are described. The electrocatalytic behavior is exploited for developing a highly stable and sensitive flow‐detection scheme for simple alcohols with a constant‐potential operation (+0.4 V vs. Ag/AgCl). The optimization of the system with respect to variables such as pH, flow rate, operating potential, and RuO₂–surface “loading” is reported. The electrode response as stable over 2 weeks with a signal loss of 6%. Repeated injections (60) of methanol over a 120 minute period yielded a relative standard deviation of 3.4%. Detection limits for the various alcohols are dependent on the number and position of the hydroxyl groups, with limits ranging from 30 ng for glycerol to 3 μg for ethanol. Use of these electrodes in liquid chromatography with electrochemical detection is envisaged.