2011 Product Catalogue - Specac

Specac Product Catalogue 2011 | Spectroscopist’s Hints and Tips
Spectroscopist’s Hints and Tips
The following hints and tips on Infrared Sampling may help you achieve better spectra with
greater ease. Don’t forget to contact your local Specac representative if you need any help
with your application. Contact details are listed at the back of this catalogue.
Transmission Measurements
Always wear gloves when handling all infrared
windows to avoid contamination. This is good
practice even for non-hygroscopic windows.
For accessories that are, or maybe, out of
alignment, a small beam white light source is
ideal for recreating the beam path. Once rough
alignment has been recovered, use the energy
level output on the spectrometer in order to finetune
the signal.
Test the identity of an unknown window or crystal
by measuring the transmission characteristics in
the spectrometer. Be aware that the cut-off
values quoted in transmission characteristics
tables are typically for short pathlengths of a few
millimeters. Longer paths through ATR crystals
will reduce the absorption cut-off back towards
shorter wavelengths.
When using a temperature controlled accessory,
always remember to set the temperature to
20ºC after use. This will remove the risk of
accidentally heating the accessory the next time
it is switched on.
104
Always check the chemical compatibility of a
window or crystal material by using scrap
fragments. If in doubt, contact your local
Specac representative for assistance.
When cleaning accessory optics it is advisable to
remove the accessory from the spectrometer.
If this is undesirable, be economical with the
amount of solvent used, as large amounts of
solvent vapour can have an effect on subsequent
spectra. It is also advisable to purge the
accessory before use.
Choosing Fluorolube as a mulling agent allows
the study of all CH stretching bands in an infrared
spectrum using the mull technique. These are
masked by paraffin absorptions when using
Nujol.
The use of an O-ring on the plunger body of an
evacuable pellet die prevents the plunger falling
onto the newly pressed disk when removing the
disk from the body of the die.
Fingerprints can be removed from mirrors by
slowly dragging a methanol soaked lens tissue
over the surface of the mirror. Use a stream of
dry air to remove excess solvent.
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