scholarly journals Aquaphotomics Reveals Subtle Differences between Natural Mineral, Processed and Aged Water Using Temperature Perturbation Near-Infrared Spectroscopy

2021 ◽  
Vol 11 (19) ◽  
pp. 9337
Author(s):  
Yasuhiro Kato ◽  
Jelena Munćan ◽  
Roumiana Tsenkova ◽  
Dušan Kojić ◽  
Masato Yasui ◽  
...  

Current approaches to the quality control of water are unsatisfying due to either a high cost or the inability to capture all of the relevant information. In this study, near-infrared spectroscopy (NIRS) with aquaphotomics as a novel approach was assessed for the discrimination of natural, processed and aged water samples. Temperature perturbation of water samples was employed to probe the aqueous systems and reveal the hidden information. A radar chart named an aquagram was used to visualize and compare the absorbance spectral patterns of waters at different temperatures. For the spectra acquired at a constant temperature of 30 °C, the discrimination analysis of different water samples failed to produce satisfying results. However, under perturbation by increasing the temperature from 35 to 60 °C, the absorbance spectral pattern of different waters displayed in aquagrams revealed different, water-specific dynamics. Moreover, it was found that aged processed water changed with the temperature, whereas the same processed water, when freshly prepared, had hydrogen bonded structures unperturbed by temperature. In summary, the aquaphotomics approach to the NIRS analysis showed that the water absorbance spectral pattern can be used to describe the character and monitor dynamics of each water sample as a complex molecular system, whose behavior under temperature perturbation can reveal even subtle changes, such as aging and the loss of certain qualities during storage.

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.


2017 ◽  
Vol 17 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Marko Gröger ◽  
Matthias Lange ◽  
Knut Rennert ◽  
Tobias Kaschowitz ◽  
Holger Plettenberg ◽  
...  

2014 ◽  
Vol 6 (14) ◽  
pp. 5008-5015 ◽  
Author(s):  
Xingyi Huang ◽  
Ernest Teye ◽  
Livingstone K. Sam-Amoah ◽  
Fangkai Han ◽  
Liya Yao ◽  
...  

This work measures the total polyphenols content in cocoa beans by using a novel approach of integrating near infrared spectroscopy and electronic tongue, 110 samples of cocoa beans were analysed.


NIR news ◽  
2018 ◽  
Vol 29 (7) ◽  
pp. 13-16 ◽  
Author(s):  
Krzysztof B Beć ◽  
Justyna Grabska

Analytical near-infrared spectroscopy has been evolving rapidly over the last decades reaching a remarkable value for both industrial and institutional laboratories nowadays. Its growth has been strongly connected to focussed development of the instrumentation and multi-variate analytical methods. Multi-variate analysis gives near-infrared spectroscopy the desired analytical performance level but lacks the ability to provide physical insights into the analysed molecular system. Large amount of information carried in an NIR spectrum is omitted in analytical routines. In the present article, we review the latest accomplishments in cross-field research aimed at connecting the basic and analytical near-infrared spectroscopy. An example of thymol molecule, an important constituent of a traditional herbal medicine Thymi herba, is discussed. The key novelty in this case is computer simulation of NIR spectra which allows gaining better understanding of how spectra forming factors correspond to the partial least squares regression coefficients with special attention paid to the role of intermolecular interactions.


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