and may include a variety of test methods.
through the vials inside the sample holder and measures the
amount of light or frequencies absorbed, which is proportional to the pressure inside the vial. Although this test provides a
quantitative result that illustrates whether a container is leaking, it cannot pinpoint the location of the leak.
This rapid test can be conducted on a wide variety of containers ranging in size from 1mL to 2L; however, the containers must be transparent. There must be sufficient headspace
in the container through which light can pass and acquire a
reading. The test cannot be used on syringes, but it may prove
more accurate than either dye ingress or vacuum decay testing.
Helium leak is a highly sensitive test method that provides
the most accurate and reproducible results. This instrument
uses a mass spectrometer to detect the rate of helium leaking
from a sealed container. It only detects helium ions, so the
presence of other gases within the vial or atmosphere does not
matter. The use of helium provides a safer alternative to other
gases such as hydrogen, which is unstable and highly explosive.
The vials or syringes can either arrive pre-filled with helium or
be filled manually. Vials can contain either liquids or lyophilized
product but syringes must be empty. Various sizes of chambers
attach to the instrument, which allow for the size of the contain-
19 March 2014 • www.cemag.us
Figure 1: In the headspace analysis method, light passes through
the vials inside the sample holder and measures the amount of light
or frequencies absorbed.