Agilent Technologies 4200 FlexScan, Руководство по эксплуатации

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Analyzing Samples
Agilent 4200 FlexScan FTIR Operation Manual 27
3
Click the Next button on the software screen to proceed with the
analysis. Clicking the Home button will stop the measurement
and return you to the Home screen.
4
For detailed software instructions for measuring a sample, refer
to the MicroLab Software Operation Manual.
5
After completing the sample measurement, immediately clean the
sample from the accessory using the instructions provided above.
6
For detailed software instructions on reviewing results and
handling sample data, refer to the MicroLab Software Operation
Manual.
Internal reflectance (ATR)
The 4200 FlexScan FTIR instrument can be provided with a
dedicated sampling probe interface called the attenuated total
reflectance (ATR) probe. The ATR takes advantage of the physical
properties of light when encountering two materials with differences
in index of refraction. When coming in contact with a sample having
a different index of refraction, the infrared (IR) light creates an
evanescent wave that provides a very small and specific depth of
penetration into the sample before reflecting back into the detector
of the 4200 FlexScan FTIR 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 an ATR is making good contact between
the sample and ATR crystal of the sampling device. The ATR
technique can be used for analysis of liquids, pastes, powders and
even some solid samples.
The Agilent ATR uses a type IIa synthetic diamond crystal as the
interface between the sample and the infrared energy. The diamond
provides the advantage of extreme hardness as well as chemical
resistivity. Diamond can accept samples with a pH range from 1 to
14, which means hard or abrasive samples and even strong acids can
be safely analyzed. The Agilent 4200 FlexScan FTIR ATR sampling
probe is a single reflection system. The diamond is the world’s most
durable substance and the ZnSe monolithic substrate is used as a
focusing lens to provide the maximum IR signal.