3.1 The oxygen content of a package's headspace is an important determinant of the packaging protection afforded by barrier materials. The package under test is typically MAP (modified atmosphere packaging) packaged.

3.2 Oxygen content is a key contributor to off-flavors and spoilage of various products, such as chemicals, food and pharmaceuticals.

3.3 The method determines the oxygen in a closed package headspace. This ability has application in:

3.3.1 Package Permeability Studies-The change of headspace composition over a known length of time allows the calculation of permeation. Since the headspace oxygen is measured as a percentage, the volume of the container's headspace must be known to allow conversion into a quantity such as millilitres (ml) of oxygen. The use of this approach to measure permeation generally applies to empty package systems only as oxygen uptake or outgassing of contained products could affect results.

3.3.2 Leak Detection-If the headspace contains more oxygen than expected or is increasing faster than expected, a leak can be suspected. A wide variety of techniques can be employed to verify that a leak is present and to identify its location. If necessary or of interest, a leak rate may be calculated with known headspace volume and measured oxygen concentration change over time.

3.3.3 Efficacy of the MAP Packaging Process-If the headspace oxygen concentration is found to be higher than expected soon after packaging, the gas flushing process may not be working as well as expected. Various techniques can evaluate whether the MAP system is functioning properly.

3.3.4 Storage Studies-As the method is non-destructive, the headspace can be monitored over time on individual samples to insure that results of storage studies such as shelf life testing are correctly interpreted.