Narrow-gap cells were fabricated for direct amperometric measurement of alcohol content in liquid hydrocarbon mixtures. Their performance has been investigated using methanol, ethanol, n-propanol as sample components (ethanol was in most details studied). One type of the insulating materials was applied in order to obtain two copper discs. The surfaces of the copper microdiscs were covered with a CuxS modifying layer. The other cell constructed in the similar way had a carbon disc working electrode (with diameter of 30 µm and copper reference/counter electrode 0.3 mm). The amperometric behaviour of the alcohols have been investigated in toluene and n-heptane solvents without background electrolyte. The amperometric current was found proportional to the ethanol concentration in the investigated range of 0.5–11 v/v%. The sensor’s performance was also tested with ethanol containing fuel products from a gas station.