Metrohm NIRS XDS Process Analyzer – SingleFiber - Manual (Page 8)

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Introduction
The XDS Process Analytics Single Fiber Multiplexer Instrument uses Near Infrared (NIR) energy to
determine chemical and physical characteristics of the sample. The sample is illuminated with white
light, and the signal returning is broken down into visible and NIR wavelengths for spectroscopic
analysis.
Single Fiber Optics provide for long runs to the sample point, which is typically a clear to semi-clear
liquid. Multiplexing permits one instrument to monitor multiple points for economy of scale.
Vision Software® is used for this analysis. Vision® has a complete suite of analysis methods for both
quantitative measurement, and for qualitative analysis. The quantitative tools permit measurement of
specific constituents (analytes) within a given product. The qualitative tools permit identification (ID)
of product, as well as “qualification” to determine the suitability of that product, as compared to
previously scanned samples.
The XDS Process Analytics Instrument is able to distinguish between very small absorbance
differences at each data interval (0.5nm). By scanning samples of known constituent values, or
known qualitative characteristics, the user may develop a very precise measurement calibration, as
well as a library of known products, or good quality. The Analyzer is used to scan new product, and
compare the spectra to those known samples. From this analysis, the software provides accurate
predictions of analyte values, product identification, and acceptance of good quality product, based
upon developed calibration models.
1.1 Enclosure Styles
The Basic XDS Process Analytics Instrument,
shown at right, is suitable for normal factory
environments where operating temperatures
do not exceed 95°F (35°C). It is rated NEMA
4X. For warmer environments, Vortec cooling
(40°C) or air-conditioning (51°C) are available.
This unit is shown with a Transmission Probe,
where the source fiber illuminates the sample
across a fixed gap, and the signal is received
by a fiber and routed back to the instrument.
The instrument may also be used with a
transmission cell, as shown on the next page.
The multiplexer in this unit allows multiple
channels, for process lines where one
instrument may sample multiple locations.