Purging of circular dichroism instruments with high purity nitrogen is essential
to remove oxygen from the lamp housing, mono-chromator, and the sample chamber.
The presence of oxygen is detrimental for two reasons. Xenon arc lamps used
as a light sources in CD measurements produce light well into the deep UV (<170
nm). When deep ultraviolet light interacts with oxygen, ozone is produced. Ozone
causes degradation of the mirrors in the optics and is toxic, leading to respiratory
problems. The second reason for removing oxygen is that oxygen absorbs deep
UV light, thus reducing the light available for the measurement.
To prevent ozone production, the lamp and monochromator are purged with high
purity nitrogen. The actual flow of nitrogen required depends on the wavelength
of CD measurement with flow requirements generally increasing below 200 nm.
Parker domnick hunter offers a cost effective solution to the high flow, high
purity requirements of typical CD instruments offered by manufacturers like
Jasco and Applied Photophysics using the flexibility of PSA nitrogen generators
to provide a generator capable of producing up to 10ltr/min of nitrogen at 99.9965%
purity (w.r.t. oxygen) and 7barg outlet pressure.
