Gas Chromatography as a Reference Method for Moisture Determination by Near-Infrared Spectroscopy

1998 ◽  
Vol 70 (2) ◽  
pp. 390-394 ◽  
Author(s):  
Xiangji Zhou ◽  
Patricia A. Hines ◽  
Kevin C. White ◽  
Matthew W. Borer
2021 ◽  
Author(s):  
Ying Chen ◽  
Dong Yiyang ◽  
Xiang Ma ◽  
Jiaru Li ◽  
Minmin Guo ◽  
...  

Abstract Background: Taraxacum kok-saghyz (TKS), a plant native to the Tianshan valley on the border between China and Kazakhstan and inherently rich in natural rubber, inulin and other bioactive ingredients, is an important industrial crop. TKS rubber is a good substitute for natural rubber. TKS's breeding work necessitates the need to screen high-yielding varieties, hence rapid determination of rubber content is essential for the screening. Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost. Near-infrared spectroscopy analysis technology, which has developed rapidly in the field of industrial process analysis in recent years, is a green detection technology with obvious merits of fast measurement speed, low cost and no sample loss. This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots. Pyrolysis gas chromatography (PyGC), was chosen as the reference method for the development of NIR prediction model. Results: 208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China. Near-infrared spectra were acquired for all samples. Randomly two-thirds of them were selected as the calibration set, the remaining one-third as the verification set, and the partial least squares method was successfully used to establish a good NIR prediction model at 1080-1800nm with a performance to deviation ratio (RPD) of 5.54 and coefficient of determination (R2) of 0.95. Conclusions: This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland, and could greatly facilitate TKS germplasm preservation, high-yield cultivation, environment-friendly, high-efficiency and low-cost rubber extraction, and comprehensive advancement of the dandelion rubber industry thereof.


2018 ◽  
Vol 26 (4) ◽  
pp. 245-261 ◽  
Author(s):  
Sanette van der Merwe ◽  
Marena Manley ◽  
Merrill Wicht

The high demand for omega-3 fish oil nutraceuticals (dietary supplements) is due to the numerous health benefits contributed by the polyunsaturated fatty acids. The nutraceutical industry is required to follow good manufacturing practice standards in order to ensure label claims and prevent adulteration. It is vital that the quality control procedures will be able to detect adulterated products. It is thus necessary to ensure that the analytical techniques are adequate by using validated methods. The qualification or identification of natural fish oils is a difficult task due to overlapping concentration ranges of polyunsaturated fatty acids and other similar properties. Gas chromatography is the prescribed technique in the nutraceutical industry for analysis of omega-3 fatty acids, but it is time-consuming and costly. Near infrared spectroscopy is a rapid and cost-effective technique which can replace the prescribed method if it is proven to be equivalent, through validation, to the criteria as prescribed by the pharmacopoeias and other industry guidelines. In this study, near infrared spectroscopy in combination with chemometrics was considered as an alternative method to gas chromatography to identify various commercial fish oils and to quantify the polyunsaturated fatty acids. Identification methods were developed for nine commercial omega-3 fish oils by using spectral libraries. Quantitative near infrared methods were developed for arachidonic acid, docosahexaenoic acid and eicosapentaenoic acid in fish oils expressed as mg.g−1 as well as % area using partial least squares regression and independent validation by superimposing datasets with mutual properties. Based on the statistics in terms of standard error of calibration, R2, standard error of prediction and r of the polyunsaturated fatty acid models, the near infrared method was equivalent to the prescribed gas chromatography methods, and precision results obtained were also within the prescribed criteria. Near infrared spectroscopy and chemometrics can be used for conclusive identification and quantification of omega-3 fish oils, thereby minimizing the risk of adulteration. The method also complied with the prescribed pharmaceutical method validation criteria, and therefore was proven as an alternative method to gas chromatography for the nutraceutical industry.


Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3145
Author(s):  
Moritz Salzmann ◽  
Yannick Blößl ◽  
Andrea Todorovic ◽  
Ralf Schledjewski

Near-infrared spectroscopy (NIR) was implemented in the resin transfer molding (RTM) process to inline monitor the degree of curing of a bio-based epoxy resin, which consists of epoxidized linseed oil (resin) and citric acid (hardener), respectively. A NIR micro-spectrometer was used for the development of robust calibration models using partial least squares (PLS) regression. Since the micro-spectrometer offers a smaller wavelength range compared with conventional NIR devices, and typical absorbance peaks are not directly involved in the captured data range, the results show new insights for the utilization of this technology. Different pre-treatments of the spectroscopic data have been tested, starting with different reference spectra, i.e., uncured resin and polytetrafluorethylene (PTFE), and followed by chemometrical algorithms. As a reference method for the degree of curing, direct current (DC) supported by differential scanning calorimetry (DSC) was used. The results show the potential of these cost-efficient and compact NIR micro-spectrometers for the intended inline monitoring purpose to gain relevant information feedback during the process.


2020 ◽  
pp. 096703352096379
Author(s):  
Qian-Fa Liu ◽  
Dan Li ◽  
Yao-De Zeng ◽  
Wei-Zhuang Huang

Gel time of prepreg is an important quality determinant in the manufacturing process of Copper Clad Laminate (CCL). Prepreg consists of a glass fiber reinforcement impregnated to a predetermined level with a resin matrix. In this work, near infrared spectroscopy associated with partial least squares (PLS) regression has been applied to analyse the gel time of prepreg samples in the manufacturing process. A total of 250 prepreg samples were randomly divided into a calibration set and a validation prediction set with a ratio of 4:1. The values of Root Mean Square Error of leave-one-out Cross-Validation (RMSECV) and the coefficient of determination (R2) of the calibration model was 2.95 s and 0.92 respectively, with eight PLS factors used. The results of the paired t-test revealed that there was no significant difference between the NIR method and the reference method. The analytical result showed that, NIR spectroscopy was a rapid, nondestructive, and accurate method for real-time prediction of prepreg quality in the CCL manufacturing process.


2015 ◽  
Vol 23 (4) ◽  
pp. 245-253 ◽  
Author(s):  
Raquel Cama-Moncunill ◽  
Maria Pietat Casado ◽  
Yash Dixit ◽  
Denisio Togashi ◽  
Laura Alvarez-Jubete ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Dana Maria Muntean ◽  
Cristian Alecu ◽  
Ioan Tomuta

Near-infrared spectroscopy (NIRS) is a technique widely used for rapid and nondestructive analysis of solid samples. A method for simultaneous analysis of the two components of paracetamol and caffeine from powder blends has been developed by using chemometry with near-infrared spectroscopy (NIRS). The method development was performed on samples containing 80, 90, 100, 110, and 120% active pharmaceutical ingredients, and near-infrared spectroscopy (NIRS) spectra of prepared powder blends were recorded and analyzed in order to develop models for the prediction of drug content. Many calibration models were applied in order to perform quantitative determination of drug content in powder, and choosing the appropriate number of factors (principal components) proved to be of highly importance for a PLS chemometric calibration. Once the methods were developed, they were validated in terms of trueness, precision, and accuracy. The results obtained by NIRS methods were compared with those obtained by HPLC reference method, and no significant differences were found. Therefore, the NIR chemometry methods were proved to be a suitable tool for predicting chemical properties of powder blends and for simultaneous determination of active pharmaceutical ingredients.


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