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NIR Spectroscopy (nir + spectroscopy)
Selected AbstractsComparison of FTIR, FT-Raman, and NIR Spectroscopy in a Maple Syrup Adulteration StudyJOURNAL OF FOOD SCIENCE, Issue 6 2002M. M. Paradkar ABSTRACT: Maple syrup is prone to adulteration with cheaper sugars, such as corn syrup, due to its simplicity in chemical composition. The adulterated samples were characterized by Fourier Transform infrared (FTIR) spectroscopy in the region of 400 to 4000 cm -1. Other techniques used for detection and in characterization of samples were the near infrared (NIR; 600 to 1700nm) and Fourier Transform-Raman (FT-Raman; 400 to 4000cm -1) spectroscopy. Quantifying and classifying adulterants using chemometrics shows that all spectroscopic methods adopted were efficient, but FTIR and FT-Raman were superior to NIR in quantitative characterization of adulterants in maple syrup. [source] Bayesian regularization: application to calibration in NIR spectroscopyJOURNAL OF CHEMOMETRICS, Issue 11 2009C. E. Alciaturi Abstract The use of a Bayesian regularization algorithm is proposed for calibration in near-infrared spectroscopy (NIR) with linear models. The algorithm used in this work is based upon the concepts developed by MacKay for inference and model comparison in artificial neural networks. It is demonstrated that this algorithm is fast, easy to use, and shows good generalization properties without previous dimensionality reduction. Examples are shown for NIR spectroscopy calibration and synthetic data. Copyright © 2009 John Wiley & Sons, Ltd. [source] Application of two-dimensional near-infrared (2D-NIR) correlation spectroscopy to the discrimination of three species of DendrobiumJOURNAL OF CHEMOMETRICS, Issue 9 2009Caiyun Wang Abstract The objective of this paper was to apply two-dimensional (2D) near-infrared (NIR) correlation spectroscopy to the discrimination of three species of Dendrobium. Generalized 2D-NIR correlation spectroscopy was able to enhance spectral resolution, simplify the spectrum with overlapped bands and provide information about temperature-induced spectral intensity variations that was hard to obtain from one-dimensional NIR spectroscopy. The FT-NIR spectra were measured over a temperature range of 30,140°C. The 2D synchronous and asynchronous spectra showed remarkable differences within the range of 5600,4750,cm,1 between different species of Dendrobium. Copyright © 2009 John Wiley & Sons, Ltd. [source] A systematic evaluation of the benefits and hazards of variable selection in latent variable regression.JOURNAL OF CHEMOMETRICS, Issue 7 2002Part II. Abstract Leave-multiple-out cross-validation (LMO-CV) is compared to leave-one-out cross-validation (LOO-CV) as objective function in variable selection for four real data sets. Two data sets stem from NIR spectroscopy and two from quantitative structure,activity relationships. In all four cases, LMO-CV outperforms LOO-CV with respect to prediction quality, model complexity (number of latent variables) and model size (number of variables). The number of objects left out in LMO-CV has an important effect on the final results. It controls both the number of latent variables in the final model and the prediction quality. The results of variable selection need to be validated carefully with a validation step that is independent of the variable selection. This step needs to be done because the internal figures of merit (i.e. anything that is derived from the objective function value) do not correlate well with the external predictivity of the selected models. This is most obvious for LOO-CV. LOO-CV without further constraints always shows the best internal figures of merit and the worst prediction quality. Copyright © 2002 John Wiley & Sons, Ltd. [source] PREDICTION OF TEXTURE IN GREEN ASPARAGUS BY NEAR INFRARED SPECTROSCOPY (NIRS)JOURNAL OF FOOD QUALITY, Issue 4 2002D. PEREZ NIR spectroscopy was used to estimate three textural parameters of green asparagus: maximum cutting force, energy and toughness. An Instron 1140 Texturometer provided reference data. A total of 199 samples from two asparagus varieties (Taxara and UC-157) were used to obtain the calibration models between the reference data and the NIR spectral data. Standard errors of cross validation (SECV) and r2 were (5.73, 0.84) for maximum cutting force, (0.58, 0.66) for toughness, and (0.04, 0.85) for cutting energy. The mathematical models developed as calibration models were tested using independent validation samples (n =20); the resulting standard errors of prediction (SEP) and r2 for the same parameters were (6.73, 0.82), (0.61, 0.57) and (0.04, 0.89), respectively. For toughness, substantially improved r2 (0.85) and SEP (0.36) when four samples exhibiting large residual values were removed. The results indicated that NIRS could accurately predict texture parameters of green asparagus. [source] SENSORY QUALITY CRITERIA FOR FIVE FISH SPECIES PREDICTED FROM NEAR-INFRARED (NIR) REFLECTANCE MEASUREMENTJOURNAL OF FOOD QUALITY, Issue 5 2001KARIN WARM ABSTRACT Sensory profiling and Near-Infrared (NIR) reflectance analysis were carried out on cod (Gadus morhua), saithe (Pollachius virens), rainbow trout (Salmo gardineri), herring (Clupea harengus) and flounder (Platichthys flessus). A nine-member trained panel performed the profiling on cooked fillet samples and NIR was measured on the same material as whole, raw fish and raw fillet. For each species, samples varied in storage time (1,11 days in ice at OC) and season (spring, autumn and winter). One descriptive vocabulary was developed, containing 46 descriptive words altogether: 7 for appearance, 15, odor, 16, taste and 8 texture words. Multivariate data analysis was used to reduce the 46 words to 18, covering the main systematic variations in appearance, odor, taste and texture in conformance with a previous study. The same 18 sensory attributes were modeled by NIR measurements on whole, new fish and fillet. The predictive results showed explained variances to be higher for appearance and texture rhan for odor, and lowest for taste. The results indicate that NIR spectroscopy of raw fish as a supplement to sensory analysis might be useful as a rapid tool in Quality Monitoring for measuring the sensory parameters of appearance and texture of cooked fish. [source] Ghanaian Cocoa Bean Fermentation Characterized by Spectroscopic and Chromatographic Methods and ChemometricsJOURNAL OF FOOD SCIENCE, Issue 6 2010Patrick C. Aculey Abstract:, Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent, unpleasant taste, and flavor, and has to be fermented, dried, and roasted to obtain the characteristic cocoa flavor and taste. In an attempt to obtain a deeper understanding of the changes in the cocoa beans during fermentation and investigate the possibility of future development of objective methods for assessing the degree of fermentation, a novel combination of methods including cut test, colorimetry, fluorescence spectroscopy, NIR spectroscopy, and GC-MS evaluated by chemometric methods was used to examine cocoa beans sampled at different durations of fermentation and samples representing fully fermented and dried beans from all cocoa growing regions of Ghana. Using colorimetry it was found that samples moved towards higher,a* and,b* values as fermentation progressed. Furthermore, the degree of fermentation could, in general, be well described by the spectroscopic methods used. In addition, it was possible to link analysis of volatile compounds with predictions of fermentation time. Fermented and dried cocoa beans from the Volta and the Western regions clustered separately in the score plots based on colorimetric, fluorescence, NIR, and GC-MS indicating regional differences in the composition of Ghanaian cocoa beans. The study demonstrates the potential of colorimetry and spectroscopic methods as valuable tools for determining the fermentation degree of cocoa beans. Using GC-MS it was possible to demonstrate the formation of several important aroma compounds such 2-phenylethyl acetate, propionic acid, and acetoin and the breakdown of others like diacetyl during fermentation. Practical Application:, The present study demonstrates the potential of using colorimetry and spectroscopic methods as objective methods for determining cocoa bean quality along the processing chain. Development of objective methods for determining cocoa bean quality will be of great importance for quality insurance within the fields of cocoa processing and raw material control in chocolate producing companies. [source] Imaging pharmaceutical tablets with optical coherence tomographyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2010Jakob M.A. Mauritz Abstract Optical coherence tomography (OCT) is a recently developed optical technique that produces depth profiles of three-dimensional objects. It is a nondestructive interferometric method responding to refractive index variation in the sample under study and can reach a penetration depth of a few millimetres. OCT employs near-infrared (NIR) light and therefore provides a link between NIR spectroscopy and Terahertz (THz) measurements that are often used to characterise tablets. In this article we assess the potential of OCT as a reliable and practical tool in the analysis of pharmaceutical tablets and coatings. A variety of tablets were tested with different shapes, formulations and coatings. We consider the origins of contrast in the obtained images and demonstrate that it correlates strongly with the expected tablet structure. The influence of absorption and scattering are considered for the wavelength ranges used. The results show that OCT is a promising diagnostic tool with an important role to play in the tablet and coating technologies. The high measurement speed of OCT and its relative ease of implementation make it also an attractive candidate technology for in-line quality control during manufacturing. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:385,391, 2010 [source] Establishing quantitative in-line analysis of multiple solid-state transformations during dehydrationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2008Karin Kogermann Abstract The aim of the study was to conduct quantitative solid phase analysis of piroxicam (PRX) and carbamazepine (CBZ) during isothermal dehydration in situ, and additionally exploit the constructed quantitative models to analyze the solid-state forms in-line during fluidized bed drying. Vibrational spectroscopy (near-infrared (NIR), Raman) was employed for monitoring the dehydration and the quantitative model was based on partial least squares (PLS) regression. PLS quantification was confirmed experimentally using isothermal thermogravimetric analysis (TGA) and X-ray powder diffractometry (XRPD). To appraise the quality of quantitative models several model parameters were evaluated. The hot-stage spectroscopy quantification results were found to be in reasonable agreement with TGA and XRPD results. Quantification of PRX forms showed complementary results with both spectroscopic techniques. The solid-state forms observed during CBZ dihydrate dehydration were quantified with Raman spectroscopy, but NIR spectroscopy failed to differentiate between the anhydrous solid-state forms of CBZ. In addition to in situ dehydration quantification, Raman spectroscopy in combination with PLS regression enabled in-line analysis of the solid-state transformations of CBZ during dehydration in a fluidized bed dryer. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4983,4999, 2008 [source] Quality by design, part I: Application of NIR spectroscopy to monitor tablet manufacturing processJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2008Simin Hassannejad Tabasi Abstract To monitor tableting production using near infrared (NIR) spectroscopy, chemometric models were developed to analyze peak compression force, crushing strength and content uniformity. To measure tablet content uniformity, orbifloxacin tablets with drug content ranging from 60 to 90 mg were made and analyzed using ultraviolet (UV) and NIR spectroscopy. To assess the compression force and crushing strength, several batches of tablets were made on a Stokes B2 rotary tablet press and compression force was varied from 360 to 3500 lb. Principal component analysis (PCA) was used to identify tablets with regular and capped tablets breakage patterns. Comparison of statistical parameters showed that partial least squares (PLS) models gave better fit than the multiple linear regression (MLR) models. The best fit PLS models had a standard error of calibration (SEC) and a standard error of prediction (SEP) for content uniformity of 1.13 and 1.36 mg; for compression force of 69.86 and 59.48 lb and for crushing strength 0.55 kP and 0.57 kP, respectively. NIR spectroscopy in combination with multivariate modeling is a rapid and nondestructive technique that could reliably predict content uniformity, compression force and crushing strength for orbifloxacin tablets. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4040,4051, 2008 [source] Dehydration studies using a novel multichamber microscale fluid bed dryer with in-line near-infrared measurementJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2003Eetu Räsänen Abstract The purpose of this research was to study the effect of two process parameters (temperature and moisture content) on dehydration behavior of different materials using a novel multichamber microscale fluid bed dryer with a process air control unit and in-line near-infrared (NIR) spectroscopy. The materials studied were disodium hydrogen phosphates with three different levels of hydrate water and wet theophylline granules. Measured process parameters of fluid bed drying were logged, including in-line NIR signals. Off-line analyses consisted of X-ray powder diffraction patterns, Fourier transform NIR spectra and moisture contents of studied materials. During fluid bed drying, the stepwise dehydration of materials was observed by the water content difference of inlet and outlet air, the pressure difference over the bed, and the in-line NIR spectroscopy. The off-line analysis confirmed the state of solid materials. The temperature and the moisture content of the process air were demonstrated to be significant factors for the solid-state stability of theophylline. The presented setup is a material and cost-saving approach for studying the influence of different process parameters on dehydration behavior during pharmaceutical processing. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2074,2081, 2003 [source] Near infrared spectroscopy in the development of solid dosage formsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2007Eetu Räsänen The use of near infrared (NIR) spectroscopy has rapidly grown partly due to demands of process analytical applications in the pharmaceutical industry. Furthermore, newest regulatory guidelines have advanced the increase of the use of NIR technologies. The non-destructive and non-invasive nature of measurements makes NIR a powerful tool in characterization of pharmaceutical solids. These benefits among others often make NIR advantageous over traditional analytical methods. However, in addition to NIR, a wide variety of other tools are naturally also available for analysis in pharmaceutical development and manufacturing, and those can often be more suitable for a given application. The versatility and rapidness of NIR will ensure its contribution to increased process understanding, better process control and improved quality of drug products. This review concentrates on the use of NIR spectroscopy from a process research perspective and highlights recent applications in the field. [source] Determination of amorphous content in the pharmaceutical process environmentJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2007Marja Savolainen The amorphous state has different chemical and physical properties compared with a crystalline one. Amorphous regions in an otherwise crystalline material can affect the bioavailability and the processability. On the other hand, crystalline material can function as nuclei and decrease the stability of an amorphous system. The aim of this study was to determine amorphous content in a pharmaceutical process environment using near infrared (NIR) and Raman spectroscopic techniques together with multivariate modelling tools. Milling was used as a model system for process-induced amorphization of a crystalline starting material, ,-lactose monohydrate. In addition, the crystallization of amorphous material was studied by storing amorphous material, either amorphous lactose or trehalose, at high relative humidity conditions. The results show that both of the spectroscopic techniques combined with multivariate methods could be applied for quantitation. Preprocessing, as well as the sampling area, was found to affect the performance of the models. Standard normal variate (SNV) transformation was the best preprocessing approach and increasing the sampling area was found to improve the models. The root mean square error of prediction (RMSEP) for quantitation of amorphous lactose using NIR spectroscopy was 2.7%, when a measuring setup with a larger sampling area was used. When the sampling area was smaller, the RMSEPs for lactose and trehalose were 4.3% and 4.2%, respectively. For Raman spectroscopy, the RMSEPs were 2.3% and 2.5% for lactose and trehalose, respectively. However, for the optimal performance of a multivariate model, all the physical forms present, as well as the process environment itself, have to be taken into consideration. [source] A near-infrared method for the assay of cineole in eucalyptus oil as an alternative to the official BP methodJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2001Nicola D. Wilson Eucalyptus oil of British Pharmacopoeia (BP) and European Pharmacopoeia standard must contain not less than 70.0% w/w 1,8-cineole (eucalyptol). The official assay is a freezing-point method which involves the addition of o -cresol to the eucalyptus oil, whereupon the o -cresol and the 1,8-cineole form a solid complex. The assay has several disadvantages and we aim to show that near-infrared (NIR) spectroscopy is an attractive alternative to this method, in that it is simple to use, requires no sample preparation and is potentially as accurate as the traditional method. Thirty different eucalyptus oil samples were scanned on the FOSS NIRSystems 6500 Rapid Content Sampler using a reflectance vessel as sample presentation method. The cineole content of each sample was determined by the BP method and these reference data were used to construct two calibration equations for cineole content in the oils using Vision software. The mean accuracy for the NIR method differed by 1.01% or less, and the mean bias by ±0.33% or less, compared with the BP method. Calculation of the 95% confidence intervals for the slope and intercept of plots of NIR predicted values against BP method reference values showed that there was no evidence of fixed or relative systematic errors. Tests for short-term and intermediate repeatability were conducted. The standard deviation was 0.83% w/w or less and the coefficient of variation was 1.11% or less. The confidence intervals for both short-term and intermediate repeatability overlapped with that for the BP method, suggesting that there was no evidence for a difference in values obtained by the BP and NIR methods. The range of cineole contents used in the calibrations was extended by incorporating five samples of eucalyptus oil spiked with cineole, and five samples of two essential oils known to have a lower cineole content than eucalyptus oil, to give a range of 52.5 to 99.0% w/w. The mean accuracy decreased to an error of 1.26% or less and the bias to ±0.50% or less. Again, confidence intervals suggested there was no evidence for fixed or systematic errors in the NIR calibrations. We propose that NIR spectroscopy could be used as an alternative method for the determination of cineole content in eucalyptus oils. [source] Preliminary study on the use of near-infrared reflectance spectroscopy to assess nitrogen content of undried wheat plantsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2007Alejandro Morón Abstract Near-infrared reflectance (NIR) spectroscopy combined with chemometrics was used to assess nitrogen (N) and dry matter content (DM) and chlorophyll in whole-wheat plant (Triticum aestivum L). Whole-wheat plant samples (n = 245) were analysed by reference method and by visible and NIR spectroscopy, in fresh (n = 182) and dry (n = 63) presentations, respectively. Calibration equations were developed using partial least squares (PLS) and validated using full cross-validation (leave-one-out method). Coefficient of determination in calibration (R2CAL) and the standard error of cross-validation (SECV) for N content in fresh sample presentation, after second derivative, were 0.89 (SECV: 0.64%), 0.86 (SECV: 0.66%) and 0.82 (SECV: 0.74%) using the visible + NIR, NIR and visible wavelength regions, respectively. Dry sample presentation gave better R2CAL and SECV for N compared with fresh presentation (R2CAL > 0.90, SECV < 0.20%) using visible + NIR. The results demonstrated that NIR is a suitable method to assess N concentration in wheat plant using fresh samples (unground and undried). Copyright © 2006 Society of Chemical Industry [source] In-Line Monitoring of Vinyl Chloride Suspension Polymerization with Near-Infrared Spectroscopy, 1 , Analysis of Morphological PropertiesMACROMOLECULAR REACTION ENGINEERING, Issue 1 2010João Miguel de Faria Jr. Abstract It is demonstrated that during suspension polymerizations it is possible to monitor morphological characteristics of PVC resins such as bulk density, cold plasticizer absorption and average particle diameter in-line and in real time using NIR spectroscopy. NIR spectra are obtained at different experimental conditions, showing that the spectra are sensitive to changes in the PVC properties. Standard mathematical procedures (partial least squares regression) are used to build empirical models and correlate the morphological properties with the obtained NIR spectra, allowing for monitoring of the PVC morphology in-line and in real time. [source] In-line near infrared monitoring of esterification of a molten ethylene,vinyl alcohol copolymer in a twin screw extruderPOLYMER ENGINEERING & SCIENCE, Issue 11 2006Claire Barrès Near infrared spectroscopy has developed in the polymer industry as a tool for in-line monitoring of processes, particularly extrusion. However, little work is dedicated to the monitoring of chemical reactions involving polymer melts. In this paper, we examine the suitability of NIR spectroscopy for monitoring the chemical modification (catalyzed esterification) of a molten ethylene,vinyl alcohol copolymer by octanoic acid in a twin screw extruder. Extrusion samples are characterized off-line, for calibration purposes, for the three species of interest (i.e. unreacted acid, OH groups, and ester functions formed on the polymer backbone) by means of two techniques: 1H NMR, allowing all three species to be quantified, and residual (free) acid titration. However, the mass balance of free acid is not straightforward, due to loss of mass by volatilization at the vent. Therefore, 1H NMR analysis and acid titration have to be combined to allow for determination of all concentrations. Multivariate calibration is implemented here to quantify and subsequently predict the analyte concentrations by using the NIR spectroscopic data. Our calibration, based on a partial least squares regression software, provides satisfactory results in terms of correlation between actual and predicted concentrations. This work demonstrates the potential of in-line NIR spectroscopy for monitoring chemical reactions with polymer melts in extrusion. POLYM. ENG. SCI. 46:1613,1624, 2006. © 2006 Society of Plastics Engineers [source] In situ near infrared spectroscopy for analyte-specific monitoring of glucose and ammonium in streptomyces coelicolor fermentationsBIOTECHNOLOGY PROGRESS, Issue 1 2010Nanna Petersen Abstract There are many challenges associated with in situ collection of near infrared (NIR) spectra in a fermentation broth, particularly for highly aerated and agitated fermentations with filamentous organisms. In this study, antibiotic fermentation by the filamentous bacterium Streptomyces coelicolor was used as a model process. Partial least squares (PLS) regression models were calibrated for glucose and ammonium based on NIR spectra collected in situ. To ensure that the models were calibrated based on analyte-specific information, semisynthetic samples were used for model calibration in addition to data from standard batches. Thereby, part of the inherent correlation between the analytes could be eliminated. The set of semisynthetic samples were generated from fermentation broth from five separate fermentations to which different amounts of glucose, ammonium, and biomass were added. This method has previously been used off line but never before in situ. The use of semisynthetic samples along with validation on an independent batch provided a critical and realistic evaluation of analyte-specific models based on in situ NIR spectroscopy. The prediction of glucose was highly satisfactory resulting in a RMSEP of 1.1 g/L. The prediction of ammonium based on NIR spectra collected in situ was not satisfactory. A comparison with models calibrated based on NIR spectra collected off line suggested that this is caused by signal attenuation in the optical fibers in the region above 2,000 nm; a region which contains important absorption bands for ammonium. For improved predictions of ammonium in situ, it is suggested to focus efforts on enhancing the signal in that particular region. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | |||||||||||||