Abstract
An on-line near infrared analytical system was developed for on-line process analysis applications. The system includes
a near infrared spectroscopy analyzer and accessories (fibers, flow cell, diffuse reflection probes etc.). Its features and
configuration were described in detail. Good performance was acquired: the wavelength range, resolution and stray light
of spectra are 1000nm~2500nm, less than 5nm and less than 0.1%, respectively; the repeatability and uncertainty
tolerances of wavelength are less than 0.02nm and 0.1nm, respectively; the temperature-induced drift of wavelength is
less than 0.05nm/°C the slope and intercept ranges are 0.98~1.00 and -0.02~0.01 for photometric linearity, respectively;
spectrophotometric noise is 1.3×10-5 (RMS) for high-light flux and 7.0×10-5 (RMS) for low-light flux. The above
performance parameters of the analyzer meet and exceed the requirement of USP1119. Furthermore, the analyzer has
been successfully applied to the laboratory, petrochemical factory and sugar mill. A Partial Least Squares (PLS)
calibration model constructed from laboratory and factory samples was used for these applications. The application
result reveals that the analyzer can meet all requirements. All results demonstrate that the analyzer has the merits of fast
time response, excellent modeling, high accuracy and low maintenance cost and can deal with complex industrial
environment.
