Five gasoline samples from different gas stations around the Campus of the Universidade Federal de Santa Catarina (UFSC, Florianópolis, Brazil), prepared by dilution in ethanol, were analyzed in this work, four were normal (gasoline without additives) and one special (containing unknown additives that help cleaning the motor parts). The samples, collected in amber glass bottles, were immediately taken to the laboratory and analyzed in the same day. The two gasoline samples used for the method optimization were named C (from common gasoline), and the five samples used for the analytical application were named G.