Novel radiotracer method for the precise determination of water vapor transmission rate characteristics of packaging systems

A novel analytical method is described for sensitive determination of moisture transmission characteristics of packaging systems. In this method, moisture uptake is measured by a radiotracer technique that utilizes tritium-labeled water (HTO). This technique is specific for actual water ingress, unlike weight gain methods, which require blanks to correct for water absorbed by the packaging materials. Because the amount of water transmission necessary for detection decreases with increasing activity of the water in the incubation chamber, the method can be made much more sensitive than gravimetric methods. The sensitivity of the radiotracer method permitted analysis of moisture entry modes of container systems. Also described herein is the applicability of various desiccants for use in the radiotracer method, discussed in terms of isotope effects and proton exchange