A structural identification analysis of the dynamic gas-liquid film model is applied to identify its theoretically accessible parameters. The analysis was performed considering the different experimental situations found in nonstationary bubble-column reactors. The system has been modeled considering both the liquid and the gas phases in a well-mixed flow regime with a global second-order irreversible chemical reaction. To describe the mass-transfer phenomenon at the gas-liquid interface level, chemical reactions and diffusive mass transport were considered simultaneously in the liquid film. The identifiability analysis shows that the simultaneous measurement of concentrations in the liquid and the gas phases is required to determine the parameters. Furthermore, model parameters such as the diffusion coefficients, the specific interfacial area, or the film thickness cannot be uncoupled from other parameters, although the kinetic rate constants could be identified in the fast or slow chemical regimes. It is demonstrated that the specific interfacial area cannot be measured from chemical data coming from a nonstationary bubble-column reactor. This result is discussed with respect to the classical Danckwerts' method for determination of the interfacial area in gas-liquid equipment. (c) 2006 American Institute of Chemical Engineers.