Installation
Cary 100/300/4000/5000/6000i/7000 Spectrophotometers User’s Guide 37
When taking measurements at wavelengths below 200
nanometers where it is necessary to minimize the effects of
oxygen absorption bands and other absorbing species in the
atmosphere such as organic solvents (for example, acetone and
isopropanol).
When taking measurements through water-absorption bands in
the near-infrared region near 1370 and 1850 nanometers (Cary
5000/6000i/7000), and 2580 and 2750 nanometers (Cary
5000/7000).
When operational conditions are such that environmental vapors
or solid particles could cause damage to optical surfaces.
When working continuously in the ultraviolet region for long
periods. Purging will protect the optics.
To purge the instrument:
1 Ensure that the nitrogen purging system is installed according to
the requirements in the Site Preparation Guide.
2 Open the nitrogen control valve and then adjust the regulator to
provide a supply pressure between 83 and 172 kPa (12 and
25 psig).
3 Set the flowmeter valves to give the following flow rates:
Instrument: 0–20 L/min
Sample compartment: 0–10 L/min
NOTE
If samples are frequently changed, you may need to increase the flow rate
through the sample compartment.
NOTE
You can gauge the success of purging by scanning for oxygen in the UV-Vis
region and by scanning for water vapor in the NIR region (Cary 5000/6000i
/7000 only).
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