Photometric moisture analysis

Photometric Moisture Analysis This analyzer requires a light source, a filter wheel rotated by a synchronous motor, a sample cell, a detector to measure the light transmitted, and associated electronics. Water has two absorption bands in the near-infrared region at 1400 and 1900 nm. This analyzer can measure moisture in liquid or gaseous samples at levels from 5 ppm up to 100 percent, depending on other chemical species in the sample. Response time is less than 1 s, and samples can be run up to 300°C and 400 psig. 

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Successful application of NIRS greatly depends on the robustness, specificity, selectivity and transferability of the calibration. In particular, it is highly desirable to be able to support a plant analyser from a laboratory instrument. Sampling-based optical artefacts and the optical characteristics of each instrument, including mechanical and photometric errors, impair transferability of data between instruments. Collaborative NIRS projects with transfer between instruments of calibration files, equations and spectra have been described [245] and interlaboratory collaborative studies of NIRS calibration methodology (for moisture analysis) have been carried out [246]. Blanco et al. [247] have compared various calibration methods in NIR diffuse reflectance spectroscopy. An absolute procedure for instrument calibration and standardisation has been presented [248]. A cloning procedure and... 

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