A novel method has been developed for the determination of the diffusion ( D ) and solid–air partition ( K d ) coefficients of methanol in paper materials. The method used a solvent-assisted vapor absorption based headspace analysis technique to increase the driving force of the mass transfer process in the solid phase. Equations based on the established physical models described the process allowed the calculation of D and K d of methanol in paper materials from the GC signals and experimental settings. The results showed that the amount of methanol transferred from the paper sheet can be significantly increased by the presence of the assisting triacetin. The solvent-assisted vapor absorption equilibrium can be obtained in 20 min. The method also generated equations allowing for the calculation of D and K d of methanol in paper materials at any temperature. The present method is simpler and quicker than the chamber methods that are in widespread use today and should be of special interest to those concerned about the impact of food and beverage packaging on human health. [ABSTRACT FROM AUTHOR]