Assessment of Diffuse Transmission and Reflection Modes in Near-Infrared Quantification, Part 2: Diffuse Reflection Information Depth

Saeed, Muhanned; Probst, Leila; Betz, Gabriele

doi:10.1002/jps.22344

Cited by 8 publications

(7 citation statements)

References 19 publications

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“…Thus, the influence of the rotation of the screw mixing elements is negligible. Consequently, the higher variability of the diffuse reflectance signal can be attributed to scattering effects caused by clay size, number, and distribution 30, 32. The lower information depth of the diffuse reflectance signal as compared with the transmission path length may enhance this effect.…”

Section: Resultsmentioning

confidence: 99%

“…The molecular absorbance of NIR radiation is weaker than that of medium IR, enabling an analysis without sample preparation 18, 30–32. Conversely, as the response of the molecules to the exposure to NIR radiation results in complex spectra, one must rely on adequate chemometrics to extract from the data as much relevant information as possible.…”

Section: Methodsmentioning

confidence: 99%

“…A partial least squares (PLS) regression will be applied to the calibration data set and the quality of the model is assessed by the following:18, 20, 22, 30–32 The root mean square error is calculated for all samples as: where, Y measured and Y predicted are the measured and predicted values, respectively. RMSE is usually labeled as root mean square error of estimation (RMSEE) and root mean square error of prediction (RMSEP) when applied to model development and validation, respectively.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

In‐line near‐infrared spectroscopy: A tool to monitor the preparation of polymer‐clay nanocomposites in extruders

Barbas

Machado

Covas

2012

J of Applied Polymer Sci

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In-line diffuse reflectance and on-line transmission near-infrared spectroscopy (NIR) measurements are performed at the same location of the barrel of a twin screw extruder during the preparation of a polypropylene/clay nanocomposite. Their performance is evaluated by means of a 7-parameter chemometric model using off-line rheological and structural (FTIR) data obtained from samples prepared under different screw speed, compatibilizer content and clay loading, as well as a process-related thermomechanical index. Despite the higher variability of the diffuse reflectance signal, the two models present analogous high quality indices. The aptness of the reflectance measurements is thus validated, which has direct practical advantages, as this probe can be fixed in any typical melt pressure transducer port. The probe is then used for the real-time in-line monitoring of the production of the same nanocomposite but now using different throughputs, and the chemometric-based predictions are compared with experimental off-line characterization data. The nonlinear effect of throughput is correctly anticipated.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

In‐line near‐infrared spectroscopy: A tool to monitor the preparation of polymer‐clay nanocomposites in extruders

Barbas

Machado

Covas

2012

J of Applied Polymer Sci

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“…4,5 Transmission measurements have been shown to be less affected by sample inhomogeneity. 3,5,[8][9][10][11] For example, comparable spectra were obtained for bilayer tablets irrespective of which of the two layers was uppermost, 12 and more accurate prediction of the two forms of carbamazepine in bilayer tablets was attainable with transmission measurements. 13 However, when the inhomogeneity was in the direction perpendicular to the axis of irradiation, then both measurement modes were found to be affected.…”

Section: Introductionmentioning

confidence: 84%

“…10 However, the depth of penetration is both wavelength and material dependent. 15 In comparison, transmission NIR measurements have a larger sampling volume; 3,10,11 it has been estimated that .90% of the transmission NIR signal comes from the central 7 mm section of a typical 10 mm diameter pharmaceutical tablet, 16 and in transmission mode light propagates through the entire thickness of the tablet. Theoretical models have been devised to describe the propagation of light through diffusely scattering multilayered materials.…”

Section: Introductionmentioning

confidence: 99%

Variation in the Transmission Near-Infrared Signal with Depth in Turbid Media

Kellichan

Nordon²,

Matousek

et al. 2014

Appl Spectrosc

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This version is available at https://strathprints.strath.ac.uk/48376/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. Transmission near-infrared (NIR) measurements of a 1 mm thick aspirin disk were made at different positions as it was moved through a stack of eight 0.5 mm thick disks of microcrystalline cellulose (Avicel). The magnitude of the first derivative of absorbance for the aspirin interlayer at 8934 cm À1 was lower when the disk was placed at the top or bottom of the stack of Avicel disks, with the largest signal observed when the aspirin was positioned at the central positions. The variation in signal with depth is consistent with that observed previously for transmission Raman spectrometry. In both cases, the trend observed can be attributed to lower photon density at the air-sample interface, relative to the center of the sample, owing to loss of photons to the air. This results in a reduction in the number of photons absorbed or Raman photons generated and subsequently detected when the interlayer occupies a near-surface position.

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The Use of Near-Infrared and Microwave Resonance Sensing to Monitor a Continuous Roller Compaction Process

Austin

Gupta

McDonnell

et al. 2013

Journal of Pharmaceutical Sciences

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Assessment of Diffuse Transmission and Reflection Modes in Near-Infrared Quantification, Part 2: Diffuse Reflection Information Depth

Cited by 8 publications

References 19 publications

In‐line near‐infrared spectroscopy: A tool to monitor the preparation of polymer‐clay nanocomposites in extruders

In‐line near‐infrared spectroscopy: A tool to monitor the preparation of polymer‐clay nanocomposites in extruders

Variation in the Transmission Near-Infrared Signal with Depth in Turbid Media

The Use of Near-Infrared and Microwave Resonance Sensing to Monitor a Continuous Roller Compaction Process

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