BUCHI NIRFlex N-500 - Manual (Page 20)

4 Description of function
20 NIRFlex N-500 Operation Manual, Version F
Data processing and interferogram analysis
The NIR light interacts with the sample G material in different ways, leaving a characteristical finger-
print on the interferogram. At liquids the light is mostly transmitted and at solids reflected. The
remaining light is collected by the detector H. The built-in computer further processes the raw signal.
Process steps Result
Signal preprocessing Interferogram
Fourier transformation Raw spectrum
Signal background correction Spectrum of sample
Chemometric analysis of the spectral data Sample analysis
Display of the result via NIRWare Operator on the attached monitor Sample analysis is displayed
4 .2 Measuring cells and their modes
The NIRFlex N-500 system is of modular design. The interferometer is located in the basic instrument.
Different measuring cell modules for different kinds of sample materials can be easily attached to the
basic intrument. To choose the best measuring cell for a specific range of samples the optical proper-
ties of the sample material must be know.
Measuring cell matrix
Sample characteristics
(for NIR light)
Section Measuring cell Typical application
Diffuse reflection 4.2.1 NIRFlex Solids;
NIRFlex Fiber Optic Solids;
NIRFlex Fiber Optic SMA* Predominantly non-translucent
materials such as most tablets,
cereals and powders
Transmission 4.2.3 NIRFlex Liquids;
NIRFlex Fiber Optic Liquids
NIRFlex Fiber Optic SMA* Translucent and transparent liquids
Diffuse transmission 4.2.4 NIRFlex Solids Transmittance Predominantly translucent solids
such as some tables, crystal
powders and other light conducting
materials
Transflectance 4.2.5 NIRFlex Fiber Optic Solids / NIRFlex
Solids with Transflectance Adapter;
NIRFlex Fiber Optic SMA* Solids with weak diffuse reflection
and low transmission rate charac-
teristics
*Depending on the custom accessory
and measurement setup