In this work, a novel sol-gel-based procedure to obtain solid carbon composite electrodes is proposed. The procedure is based on the use of sonocatalysis to apply high-energy ultrasound directly to the precursors; this way, ultrasonic cavitation is achieved so that hydrolysis with acidic water is promoted in the absence of any additional solvent and the time needed to get a unique phase is reduced drastically. The mix of sonogel with spectroscopic grade graphite leads to a new type of sol-gel electrode: the Sonogel-Carbon electrode. The amount of water, necessary for hydrolysis to occur, has been studied, as well as the sol pH value and the electrochemical behavior of the Sonogel-Carbon electrode in Britton-Robinson buffer. Mechanical renewal of the electrodes surfaces and background signal stability for at least 42 days have been also tested. We have carried out some tests to check the ability of the synthesized material to give electrochemical response when redox species are present in the background electrolyte. Mechanical and electrochemical studies indicate that the Sonogel-Carbon electrode shows good properties for use as an electrochemical sensor.

The electrochemical behavior of a sonogel-carbon electrode towards nine phenolic compounds (chloro-, nitro-and alkyl-phenols) was studied; one of them (4-chloro-3-methylphenol) was used to evaluate characteristics of the electrode, such as accumulation and cleaning procedure of the electrode surface, reproducibility of the measurements, and influence of time from fabrication on electrochemical response. A polyethyleneglycol-modified sonogel-carbon electrode was found to improve the electrochemical response towards the analyte. A linear relationship between peak height and concentration in the range 0.005 -0.5 mg L À1 was obtained, with a detection limit of 2.8 mg L À1. The studies of electrochemical parameters, as well as interferences, are also included.