Amperometric sensors based on synthetic hydrotalcites and their application for ethanol detection in beer

The electrochemical and electrocatalytic behavior of electrodes modified with a Co/Al-NO3 hydrotalcite (HT) has been investigated and compared with that displayed by Ni/Al-NO3 HT modified electrodes. Mono and polyhydric compounds have been tested to study electrocatalysis. At Co/Al-NO3 HT modified electrodes only polyhydric compounds give e current signal, whereas at Ni/Al-NO3 HT modified electrodes, both alcohols and polyhydric compounds can be detected. The different electrocatalytic behavior of Ni and Co based electrodes has been exploited to develop an analytic method for the selective determination of alcohols in the presence of polyhydric compounds. Samples of beer found on the Italian market have been analyzed to verify the validity of the proposed method in the detection of the ethanol content. The procedure does require neither a preliminar treatment nor a separation of the sample, but only the recording of two cyclic voltammogramms, one with the Co/Al-NO3 and one with the Ni/Al-NO3 HT modified electrode. The results obtained have been promising.