A biomimetic sensor for aliphatic hydrocarbons is presented. The sensor is based on the combination of a screen printed peroxidase electrode and an iron porphyrin complex iron(III)-meso-tetrakis-(pentafluorophenyl)-beta-tetrasulfonatoporphyrin chloride. The biomimetic compound was immobilized in a polyelectrolyte matrix. As the model analyte octane was chosen. Catalytic reaction is described in the homogeneous system and on the sensor surface.