3 | Product description
BÜCHI Labortechnik AG
12/94
Operation Manual ProxiMate™
3
Product description
3.1
Description of function
ProxiMate™ is a NIR spectrometer that can be used to determine the concentration
of different parameters in food and feed samples in a nondestructive way.
ProxiMate™ is supplied in different versions. Dependent on the version specified
ProxiMate™ is either an NIR or combined NIR and visible spectrometer.
The instrument generates a beam of NIR and visible light which is focused onto the
sample under investigation. Light reflected from the sample is collected and spatially
separated by a diffraction element. The diffracted light is directed onto a diode array
detector. Signals from the detector are processed and a reflectance spectrum is con-
structed. This spectrum undergoes further processing to calculate the constituents re-
quired.
Data processing
The NIR light interacts with the sample material in different ways, leaving a character-
istic fingerprint on the spectrum. Spectra from both liquids and solids can be mea-
sured with ProxiMate™. The spectra of solid samples are collected directly, liquid
samples require the use of a transflectance adapter.
Application
The Application defines all of the parameters related to measurement of a particular
sample type.
This includes:
the properties to be measured
the calibrations used
the standard operating procedure
It is possible to Import or Export a file that contains all Application data to allow the
same Application to be used on a second ProxiMate™ (dependent on calibration li-
cense requirements).
3.2
Sample presentation options
The choice of sample presentation of ProxiMate™ is optimised for the type of sample
under analysis and for the working environment where the instrument is used.
ProxiMate™ can be configured with a choice of sample presentation options: up view
and down view configurations.
3.2.1
Up view option
The up view option directs and collects light from the underside of the sample. The
NIR light passes through the base of a glass petri dish before interacting with the
sample under evaluation. Up view measurement has the advantage that a more con-
sistent surface is presented to the ProxiMate™ ensuring accurate measurement out-
put. Glass petri dishes are recommended to enable best performance. Additionally,
when used in conjunction with a transflectance adapter, it is also possible to measure
liquids using the up view option.
3.2.2
Down view option
With down view option light is focussed onto and collected from the top surface of the
sample. In areas where glass is prohibited (such as some food production areas), the
down view mode offers the advantage that NIR light does not interact with the sample
container. As plastics have their own NIR spectra, changes in type of dish can influ-
