Analyzing Samples; External Reflectance, Grazing Angle And Diffuse Reflectance - Agilent Technologies 4200 FlexScan Operation Manual

The Agilent 4200 FlexScan FTIR instrument is provided with a
sample probe interface as specified on your order. This section
covers instructions for how to analyze a sample with all sampling
probes offered on the 4200 FlexScan.

External reflectance, grazing angle and diffuse reflectance

The 4200 FlexScan FTIR instrument can be provided with three
different reflectance interfaces: external (or specular) reflectance,
grazing angle reflectance or diffuse reflectance. Each of these sample
interfaces relies on light reflecting from the sample surface. When
coming in contact with a sample, the infrared (IR) light passes
through the top surface of the sample before being reflected back out
of the sample and into the detector of the 4200 FlexScan system. This
small and consistent pathlength provides the advantage of no sample
preparation required to get good measurement results on a variety of
samples. The key to obtaining good results with external reflectance
is making sure the tip of the probe makes stable contact with the
sample surface and does not move during the measurement process.
The front of the sample interface defines the IR light focus or each of
the reflectance sample interfaces.
Agilent 4200 FlexScan FTIR Operation Manual

3. Analyzing Samples

External reflectance, grazing angle and diffuse 23
Internal reflectance (ATR) 27
Analyzing Samples
23