PerkinElmer Spotlight 400 Series, User Manual

Page: 87 / 120

Techniques for Collecting IR Images and Spectra . 87
Cleaning the ATR Objective Crystal
The ATR objective crystal is in contact with the sample under test, so it may become dirty
during use. A dirty crystal may give spectra of the contaminant rather than the sample under
test.
Great care must be taken when cleaning the crystal. It should be cleaned using the minimum
mechanical pressure, with a soft brush or lens tissue. Isopropanol or n-hexane may be used
to clean the crystal.
NOTE: Do not use acetone or xylene to clean the crystal.
1. Pour a small volume of a solvent into a shallow dish.
2. Using the Z-control on the joystick, lower the sample stage to allow the dish to be
placed on the stage under the crystal.
3. Using the Z-control on the joystick, raise the stage so that the tip of the crystal is just
immersed in the solvent.
NOTE: Do not immerse the whole of the ATR crystal in the solvent.
4. Leave the crystal in the solvent for 5 minutes.
We recommend that you do not leave the crystal in the solvent for longer periods.
5. If any material remains on the crystal, rub the crystal gently with a soft brush or lens
tissue.