molecules-logo

Journal Browser

Journal Browser

Application of Spectroscopic Sensors in Life Science and Analytical Chemistry

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (31 May 2020) | Viewed by 52372

Special Issue Editor

Biophotonics–Biomedical Engineering, Engineering Technical University Darmstadt, D-64283 Darmstadt, Germany
Interests: biophotonics; raman and infrared spectroscopy; biomedical engineering; chemical imaging; fiber sensing; gas analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue highlights recent developments in the field of Raman and infrared spectroscopy for applications in life science and analytical chemistry. Vibrational spectroscopy offers an extremely high chemical selectivity with no need for labeling or extensive sample preparation. Recent developments towards signal enhancement, miniaturization and robustness pave the way for plenty new applications in various interdisciplinary topics. Exciting fields for in-line analysis, point-of-care and onsite application are biomedical diagnostic, environmental monitoring, process analysis, investigation of pharmaceuticals, food analysis, materials development and many others.

In order to give an update of recent progresses in technique improvements and new applications, you are kindly invited to submit your original articles or reviews of your work.

Dr. Torsten Frosch
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • raman spectroscopy
  • infrared spectroscopy
  • analytical chemistry
  • life science
  • chemical sensing
  • environmental monitoring
  • biomedical diagnostics
  • chemical imaging
  • food analysis
  • pharmaceutical analysis
  • process monitoring

Published Papers (14 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

10 pages, 1925 KiB  
Article
Detection of Biomarkers Relating to Quality and Differentiation of Some Commercially Significant Whole Fish Using Spatially Off-Set Raman Spectroscopy
by Jeremy D. Landry, Peter J. Torley and Ewan W. Blanch
Molecules 2020, 25(17), 3776; https://doi.org/10.3390/molecules25173776 - 19 Aug 2020
Cited by 10 | Viewed by 2069
Abstract
Aquaculture represents a major part of the world’s food supply. This area of food production is developing rapidly, and as such the tools and analytical techniques used to monitor and assess the quality of fish need to also develop and improve. The use [...] Read more.
Aquaculture represents a major part of the world’s food supply. This area of food production is developing rapidly, and as such the tools and analytical techniques used to monitor and assess the quality of fish need to also develop and improve. The use of spatially off-set Raman spectroscopy (SORS) is particularly well-suited for these applications, given the ability of this technique to take subsurface measurements as well as being rapid, non-destructive and label-free compared to classical chemical analysis techniques. To explore this technique for analysing fish, SORS measurements were taken on commercially significant whole fish through the skin in different locations. The resulting spectra were of high quality with subsurface components such as lipids, carotenoids, proteins and guanine from iridophore cells clearly visible in the spectra. These spectral features were characterised and major bands identified. Chemometric analysis additionally showed that clear differences are present in spectra not only from different sections of a fish but also between different species. These results highlight the potential application for SORS analysis for rapid quality assessment and species identification in the aquaculture industry by taking through-skin measurements. Full article
Show Figures

Figure 1

11 pages, 1782 KiB  
Article
Rapid Raman Spectroscopic Analysis of Stress Induced Degradation of the Pharmaceutical Drug Tetracycline
by Christian Domes, Timea Frosch, Juergen Popp and Torsten Frosch
Molecules 2020, 25(8), 1866; https://doi.org/10.3390/molecules25081866 - 17 Apr 2020
Cited by 7 | Viewed by 2865
Abstract
Stress factors caused by inadequate storage can induce the unwanted degradation of active compounds in pharmaceutical formulations. Resonance Raman spectroscopy is presented as an analytical tool for rapid monitoring of small concentration changes of tetracycline and the metabolite 4˗epianhydrotetracycline. These degradation processes were [...] Read more.
Stress factors caused by inadequate storage can induce the unwanted degradation of active compounds in pharmaceutical formulations. Resonance Raman spectroscopy is presented as an analytical tool for rapid monitoring of small concentration changes of tetracycline and the metabolite 4˗epianhydrotetracycline. These degradation processes were experimentally induced by changes in temperature, humidity, and irradiation with visible light over a time period of up to 23 days. The excitation wavelength λexc = 413 nm was proven to provide short acquisition times for the simultaneous Raman spectroscopic detection of the degradation of tetracycline and production of its impurity in small sample volumes. Small concentration changes could be detected (down to 1.4% for tetracycline and 0.3% for 4-epianhydrotetracycline), which shows the potential of resonance Raman spectroscopy for analyzing the decomposition of pharmaceutical products. Full article
Show Figures

Graphical abstract

13 pages, 2700 KiB  
Article
Infrared and 2-Dimensional Correlation Spectroscopy Study of the Effect of CH3NH3PbI3 and CH3NH3SnI3 Photovoltaic Perovskites on Eukaryotic Cells
by Luca Quaroni, Iness Benmessaoud, Bertrand Vileno, Endre Horváth and László Forró
Molecules 2020, 25(2), 336; https://doi.org/10.3390/molecules25020336 - 14 Jan 2020
Cited by 6 | Viewed by 2777
Abstract
We studied the effect of the exposure of human A549 and SH-SY5Y cell lines to aqueous solutions of organic/inorganic halide perovskites CH3NH3PbI3 (MAPbI3) and CH3NH3SnI3 (MASnI3) at the molecular [...] Read more.
We studied the effect of the exposure of human A549 and SH-SY5Y cell lines to aqueous solutions of organic/inorganic halide perovskites CH3NH3PbI3 (MAPbI3) and CH3NH3SnI3 (MASnI3) at the molecular level by using Fourier transform infrared microspectroscopy. We monitored the infrared spectra of some cells over a few days following exposure to the metals and observed the spectroscopic changes dominated by the appearance of a strong band at 1627 cm−1. We used Infrared (IR) mapping to show that this change was associated with the cell itself or the cellular membrane. It is unclear whether the appearance of the 1627 cm−1 band and heavy metal exposure are related by a direct causal relationship. The spectroscopic response of exposure to MAPbI3 and MASnI3 was similar, indicating that it may arise from a general cellular response to stressful environmental conditions. We used 2D correlation spectroscopy (2DCOS) analysis to interpret spectroscopic changes. In a novel application of the method, we demonstrated the viability of 2DCOS for band assignment in spatially resolved spectra. We assigned the 1627 cm−1 band to the accumulation of an abundant amide or amine containing compound, while ruling out other hypotheses. We propose a few tentative assignments to specific biomolecules or classes of biomolecules, although additional biochemical characterization will be necessary to confirm such assignments. Full article
Show Figures

Figure 1

11 pages, 2578 KiB  
Article
Highly Sensitive Detection of the Antibiotic Ciprofloxacin by Means of Fiber Enhanced Raman Spectroscopy
by Sebastian Wolf, Timea Frosch, Juergen Popp, Mathias W. Pletz and Torsten Frosch
Molecules 2019, 24(24), 4512; https://doi.org/10.3390/molecules24244512 - 10 Dec 2019
Cited by 19 | Viewed by 3822
Abstract
Sepsis and septic shock exhibit a rapid course and a high fatality rate. Antibiotic treatment is time-critical and precise knowledge of the antibiotic concentration during the patients’ treatment would allow individual dose adaption. Over- and underdosing will increase the antimicrobial efficacy and reduce [...] Read more.
Sepsis and septic shock exhibit a rapid course and a high fatality rate. Antibiotic treatment is time-critical and precise knowledge of the antibiotic concentration during the patients’ treatment would allow individual dose adaption. Over- and underdosing will increase the antimicrobial efficacy and reduce toxicity. We demonstrated that fiber enhanced Raman spectroscopy (FERS) can be used to detect very low concentrations of ciprofloxacin in clinically relevant doses, down to 1.5 µM. Fiber enhancement was achieved in bandgap shifted photonic crystal fibers. The high linearity between the Raman signals and the drug concentrations allows a robust calibration for drug quantification. The needed sample volume was very low (0.58 µL) and an acquisition time of 30 s allowed the rapid monitoring of ciprofloxacin levels in a less invasive way than conventional techniques. These results demonstrate that FERS has a high potential for clinical in-situ monitoring of ciprofloxacin levels. Full article
Show Figures

Graphical abstract

15 pages, 6946 KiB  
Article
Fiber-Array-Based Raman Hyperspectral Imaging for Simultaneous, Chemically-Selective Monitoring of Particle Size and Shape of Active Ingredients in Analgesic Tablets
by Timea Frosch, Elisabeth Wyrwich, Di Yan, Juergen Popp and Torsten Frosch
Molecules 2019, 24(23), 4381; https://doi.org/10.3390/molecules24234381 - 30 Nov 2019
Cited by 22 | Viewed by 3737
Abstract
The particle shape, size and distribution of active pharmaceutical ingredients (API) are relevant quality indicators of pharmaceutical tablets due to their high impact on the manufacturing process. Furthermore, the bioavailability of the APIs from the dosage form depends largely on these characteristics. Routinely, [...] Read more.
The particle shape, size and distribution of active pharmaceutical ingredients (API) are relevant quality indicators of pharmaceutical tablets due to their high impact on the manufacturing process. Furthermore, the bioavailability of the APIs from the dosage form depends largely on these characteristics. Routinely, particle size and shape are only analyzed in the powder form, without regard to the effect of the formulation procedure on the particle characteristics. The monitoring of these parameters improves the understanding of the process; therefore, higher quality and better control over the biopharmaceutical profile can be ensured. A new fiber-array-based Raman hyperspectral imaging technique is presented for direct simultaneous in-situ monitoring of three different active pharmaceutical ingredients- acetylsalicylic acid, acetaminophen and caffeine- in analgesic tablets. This novel method enables a chemically selective, noninvasive assessment of the distribution of the active ingredients down to 1 µm spatial resolution. The occurrence of spherical and needle-like particles, as well as agglomerations and the respective particle size ranges, were rapidly determined for two commercially available analgesic tablet types. Subtle differences were observed in comparison between these two tablets. Higher amounts of acetaminophen were visible, more needle-shaped and bigger acetylsalicylic acid particles, and a higher incidence of bigger agglomerations were found in one of the analgesic tablets. Full article
Show Figures

Graphical abstract

17 pages, 5205 KiB  
Article
Near-Infrared Hyperspectral Imaging Combined with Deep Learning to Identify Cotton Seed Varieties
by Susu Zhu, Lei Zhou, Pan Gao, Yidan Bao, Yong He and Lei Feng
Molecules 2019, 24(18), 3268; https://doi.org/10.3390/molecules24183268 - 07 Sep 2019
Cited by 71 | Viewed by 4562
Abstract
Cotton seed purity is a critical factor influencing the cotton yield. In this study, near-infrared hyperspectral imaging was used to identify seven varieties of cotton seeds. Score images formed by pixel-wise principal component analysis (PCA) showed that there were differences among different varieties [...] Read more.
Cotton seed purity is a critical factor influencing the cotton yield. In this study, near-infrared hyperspectral imaging was used to identify seven varieties of cotton seeds. Score images formed by pixel-wise principal component analysis (PCA) showed that there were differences among different varieties of cotton seeds. Effective wavelengths were selected according to PCA loadings. A self-design convolution neural network (CNN) and a Residual Network (ResNet) were used to establish classification models. Partial least squares discriminant analysis (PLS-DA), logistic regression (LR) and support vector machine (SVM) were used as direct classifiers based on full spectra and effective wavelengths for comparison. Furthermore, PLS-DA, LR and SVM models were used for cotton seeds classification based on deep features extracted by self-design CNN and ResNet models. LR and PLS-DA models using deep features as input performed slightly better than those using full spectra and effective wavelengths directly. Self-design CNN based models performed slightly better than ResNet based models. Classification models using full spectra performed better than those using effective wavelengths, with classification accuracy of calibration, validation and prediction sets all over 80% for most models. The overall results illustrated that near-infrared hyperspectral imaging with deep learning was feasible to identify cotton seed varieties. Full article
Show Figures

Figure 1

13 pages, 1231 KiB  
Article
Identification of Passion Fruit Oil Adulteration by Chemometric Analysis of FTIR Spectra
by Johannes Kiefer, Anja I. Lampe, Stefano F. Nicoli, Massimo Lucarini and Alessandra Durazzo
Molecules 2019, 24(18), 3219; https://doi.org/10.3390/molecules24183219 - 04 Sep 2019
Cited by 17 | Viewed by 3725
Abstract
Passion fruit oil is a high-value product with applications in the food and cosmetic sectors. It is frequently diluted with sunflower oil. Sunflower oil is also a potential adulterant as its addition does not notably alter the appearance of the passion fruit oil. [...] Read more.
Passion fruit oil is a high-value product with applications in the food and cosmetic sectors. It is frequently diluted with sunflower oil. Sunflower oil is also a potential adulterant as its addition does not notably alter the appearance of the passion fruit oil. In this paper, we show that this is also true for the FTIR spectrum. However, the chemometric analysis of the data changes this situation. Principal component analysis (PCA) enables not only the straightforward discrimination of pure passion fruit oil and adulterated samples but also the unambiguous classification of passion fruit oil products from five different manufacturers. Even small amounts—significantly below 1%—of the adulterant can be detected. Furthermore, partial least-squares regression (PLSR) facilitates the quantification of the amount of sunflower oil added to the passion fruit oil. The results demonstrate that the combination of FTIR spectroscopy and chemometric data analysis is a very powerful tool to analyze passion fruit oil. Full article
Show Figures

Graphical abstract

9 pages, 1895 KiB  
Article
Investigation on the Cancer Invasion and Metastasis of Skin Squamous Cell Carcinoma by Raman Spectroscopy
by Xu Zhang, Fan Yu, Jie Li, Dongliang Song, Heping Li, Kaige Wang, Qingli He and Shuang Wang
Molecules 2019, 24(11), 2059; https://doi.org/10.3390/molecules24112059 - 30 May 2019
Cited by 12 | Viewed by 3373
Abstract
Raman spectroscopy facilitates accurate and minimally invasive investigation on biomedical samples to reveal their molecular-level biological information. In this work, the cancer field effects of squamous cell carcinoma (SCC) tissues were illustrated by Raman microspectroscopy. Referenced with hematoxylin and eosin (H&E) stained microscopic [...] Read more.
Raman spectroscopy facilitates accurate and minimally invasive investigation on biomedical samples to reveal their molecular-level biological information. In this work, the cancer field effects of squamous cell carcinoma (SCC) tissues were illustrated by Raman microspectroscopy. Referenced with hematoxylin and eosin (H&E) stained microscopic images, the biochemical variations during SCC progress were meticulously described by the Raman spectral features in different pathological areas of two lesion types, including the biochemical changes in collagen, lipids, DNA, and other components of SCC diffusion and metastasis. The experimental results demonstrated that the intensities of the Raman peaks representing collagen (853, 936, and 1248 cm−1) were decreased, whereas the intensities of peaks corresponding to DNA (720, 1327 cm−1) and lipids (1305 cm−1) were increased significantly in cancerous lesions, which testified that SCC originates from the epidermis and invades the dermis gradually. The achieved results not only described the molecular mechanism of skin carcinogenesis, but also provided vital reference data for in vivo skin cancer diagnosis using Raman spectroscopy. Full article
Show Figures

Figure 1

12 pages, 1441 KiB  
Article
Pharmaceutical Cocrystal Formation of Pyrazinamide with 3-Hydroxybenzoic Acid: A Terahertz and Raman Vibrational Spectroscopies Study
by Qiqi Wang, Jiadan Xue, Zhi Hong and Yong Du
Molecules 2019, 24(3), 488; https://doi.org/10.3390/molecules24030488 - 30 Jan 2019
Cited by 30 | Viewed by 3743
Abstract
Vibrational modes of pyrazinamide (PZA), 3-hydroxybenzoic acid (3-hBA), and their cocrystal were characterized using terahertz time-domain (THz-TDS) and Raman vibrational spectroscopic techniques. In experimental THz spectra, the cocrystal has characteristic absorption bands at around 0.81, 1.47, and 1.61 THz, respectively, meanwhile the raw [...] Read more.
Vibrational modes of pyrazinamide (PZA), 3-hydroxybenzoic acid (3-hBA), and their cocrystal were characterized using terahertz time-domain (THz-TDS) and Raman vibrational spectroscopic techniques. In experimental THz spectra, the cocrystal has characteristic absorption bands at around 0.81, 1.47, and 1.61 THz, respectively, meanwhile the raw materials are absolutely different in this region. Raman spectra also show similar results about differences between the cocrystal and corresponding starting parent materials. Density functional theory (DFT) was used to simulate both optimized structures and vibrational modes of the cocrystal formed between PZA and 3-hBA. The vibrational modes of such cocrystal are assigned through comparing the simulation DFT frequency results with experimental vibrational spectra. The calculation of the theoretical THz spectrum shows that the hydrogen bonding effect established between H11–N12–H13 and the carboxyl group -COOH makes contributions to the formation of absorption peaks in 0.49, 0.62, 0.83, and 1.61 THz, which agrees pretty well with experimental results. The theoretical Raman result also matches well with experimental observations. The results provide a fundamental benchmark for the study of pharmaceutical cocrystal formation and also inter-molecular hydrogen bonding interactions between active pharmaceutical ingredients and various cocrystal coformers based on Raman and terahertz vibrational spectroscopic techniques combined with theoretical simulations. Full article
Show Figures

Graphical abstract

10 pages, 1569 KiB  
Article
Differentiation of Taxonomically Closely Related Species of the Genus Acinetobacter Using Raman Spectroscopy and Chemometrics
by A. Margarida Teixeira, Alexandr Nemec and Clara Sousa
Molecules 2019, 24(1), 168; https://doi.org/10.3390/molecules24010168 - 04 Jan 2019
Cited by 5 | Viewed by 3798
Abstract
In recent years, several efforts have been made to develop quick and low cost bacterial identification methods. Genotypic methods, despite their accuracy, are laborious and time consuming, leaving spectroscopic methods as a potential alternative. Mass and infrared spectroscopy are among the most reconnoitered [...] Read more.
In recent years, several efforts have been made to develop quick and low cost bacterial identification methods. Genotypic methods, despite their accuracy, are laborious and time consuming, leaving spectroscopic methods as a potential alternative. Mass and infrared spectroscopy are among the most reconnoitered techniques for this purpose, with Raman having been practically unexplored. Some species of the bacterial genus Acinetobacter are recognized as etiological agents of nosocomial infections associated with high rates of mortality and morbidity, which makes their accurate identification important. The goal of this study was to assess the ability of Raman spectroscopy to discriminate between 16 Acinetobacter species belonging to two phylogroups containing taxonomically closely related species, that is, the Acinetobacter baumannii-Acinetobacter calcoaceticus complex (six species) and haemolytic clade (10 species). Bacterial spectra were acquired without the need for any sample pre-treatment and were further analyzed with multivariate data analysis, namely partial least squares discriminant analysis (PLSDA). Species discrimination was achieved through a series of sequential PLSDA models, with the percentage of correct species assignments ranging from 72.1% to 98.7%. The obtained results suggest that Raman spectroscopy is a promising alternative for identification of Acinetobacter species. Full article
Show Figures

Figure 1

15 pages, 6646 KiB  
Article
Vibrational Spectroscopy for Cocrystals Screening. A Comparative Study
by Marisa Rodrigues, João Lopes and Mafalda Sarraguça
Molecules 2018, 23(12), 3263; https://doi.org/10.3390/molecules23123263 - 10 Dec 2018
Cited by 16 | Viewed by 3806
Abstract
A recurrent problem faced by the pharmaceutical industry when formulating drug products concerns poorly soluble drugs, which, despite having desirable pharmacological activity, present limited bioavailability. Cocrystallization is growing up as a possible approach to tackle this problem. Cocrystals are crystalline materials comprising at [...] Read more.
A recurrent problem faced by the pharmaceutical industry when formulating drug products concerns poorly soluble drugs, which, despite having desirable pharmacological activity, present limited bioavailability. Cocrystallization is growing up as a possible approach to tackle this problem. Cocrystals are crystalline materials comprising at least two components, solid at room temperature, and held together by non-covalent bonds. The increasing interest in these compounds is steadily demanding faster, simpler, and more reliable methods for the task of screening new cocrystals. This work aims at comparing the performance of three vibrational spectroscopy techniques (mid infrared, near infrared, and Raman spectroscopy) for cocrystals screening. Presented results are based on hydrochlorothiazide, a poorly soluble drug belonging to class IV of the Biopharmaceutical Classification System. The implemented cocrystal screening procedure tested six coformers (all considered safe for human administration) added according to a drug:coformer ratio of 1:1 and 1:2 and seven solvents with different polarity. The screening method chosen was based on slurry cocrystallization performed by sonication (ultrasound assisted) in a 96-well plate. Results show that all evaluated vibrational spectroscopy techniques provided important information regarding cocrystal formation, including information on the groups involved in the cocrystallization and purity, and can be used for the screening task. Full article
Show Figures

Graphical abstract

10 pages, 1887 KiB  
Article
Direct Determination of Ni2+-Capacity of IMAC Materials Using Near-Infrared Spectroscopy
by Christian G. Kirchler, Raphael Henn, Julia Modl, Felix Münzker, Tanja H. Baumgartner, Florian Meischl, Alexander Kehle, Günther K. Bonn and Christian W. Huck
Molecules 2018, 23(12), 3072; https://doi.org/10.3390/molecules23123072 - 24 Nov 2018
Cited by 6 | Viewed by 4405
Abstract
The present paper reports a new method for the quantification of the Ni2+-capacity of an immobilized metal affinity chromatography (IMAC) material using near-infrared spectroscopy (NIRS). Conventional analyses using UV absorption spectroscopy or atomic absorption spectrometry (AAS) need to dissolve the silica-based [...] Read more.
The present paper reports a new method for the quantification of the Ni2+-capacity of an immobilized metal affinity chromatography (IMAC) material using near-infrared spectroscopy (NIRS). Conventional analyses using UV absorption spectroscopy or atomic absorption spectrometry (AAS) need to dissolve the silica-based metal chelate sorbent as sample pretreatment. In the first step, those methods were validated on the basis of an ideal homogenous NiSO4-solution and unveiled that UV with an intermediate precision of 2.6% relative standard deviation (RSD) had an advantage over AAS with an intermediate precision of 6.5% RSD. Therefore, UV analysis was chosen as reference method for the newly established NIRS model which has the advantage of being able to measure the material directly in diffuse reflection mode. Partial least squares regression (PLSR) analysis was used as multivariate data analysis tool for quantification. The best PLSR result obtained was: coefficient of determination (R2) = 0.88, factor = 2, root mean square error of prediction (RMSEP) = 22 µmol/g (test-set validation) or 7.5% RSDPLSR. Validation of the Ni2+-capacity using UV absorption spectroscopy resulted in an intermediate precision of ±18 µmol/g or 5.0% RSD. Therefore, NIRS provides a fast alternative analysis method without the need of sample preparation. Full article
Show Figures

Graphical abstract

10 pages, 2253 KiB  
Article
Rapid and Integrated Quality Assessment of Organic-Inorganic Composite Herbs by FTIR Spectroscopy—Global Chemical Fingerprints Identification and Multiple Marker Components Quantification of Indigo Naturalis (Qing Dai)
by Meng Pan, Wenxuan Pei, Yixin Yao, Ling Dong and Jianbo Chen
Molecules 2018, 23(11), 2743; https://doi.org/10.3390/molecules23112743 - 24 Oct 2018
Cited by 12 | Viewed by 3259
Abstract
This research aimed to develop an FTIR-based method for rapid and low-cost integrated quality assessment of organic-inorganic composite herbs, which are kinds of herbs composed of both organic and inorganic active ingredients or matrix components. A two-step quality assessment route was designed and [...] Read more.
This research aimed to develop an FTIR-based method for rapid and low-cost integrated quality assessment of organic-inorganic composite herbs, which are kinds of herbs composed of both organic and inorganic active ingredients or matrix components. A two-step quality assessment route was designed and verified using the example of Indigo Naturalis (Qing Dai). First, the FTIR spectra were used as global chemical fingerprints to identify the true and fake samples. Next, the contents of the organic and inorganic marker components were estimated by FTIR quantification models to assess the quality of the true samples. Using the above approaches, all the 56 true samples and five fake samples of Indigo Naturalis could be identified correctly by the correlation threshold of the FTIR chemical fingerprints. Furthermore, the FTIR calibration models provided an accurate estimation of the contents of marker components with respect to HPLC and inductively coupled plasma optical emission spectrometry (ICP-OES). The coefficients of determination (R2) for the independent validation of indigo, indirubin, and calcium were 0.977, 0.983, and 0.971, respectively. Meanwhile, the mean relative errors (MRE) for the independent validation of indigo, indirubin, and calcium were 2.2%, 2.4%, and 1.8%, respectively. In conclusion, this research shows the potential of FTIR spectroscopy for the rapid and integrated quality assessment of organic-inorganic composite herbs in both chemical fingerprints identification and marker components quantification. Full article
Show Figures

Graphical abstract

13 pages, 1765 KiB  
Article
Determination of Total Polysaccharides and Total Flavonoids in Chrysanthemum morifolium Using Near-Infrared Hyperspectral Imaging and Multivariate Analysis
by Juan He, Lidan Chen, Bingquan Chu and Chu Zhang
Molecules 2018, 23(9), 2395; https://doi.org/10.3390/molecules23092395 - 19 Sep 2018
Cited by 47 | Viewed by 5461
Abstract
The rapid and nondestructive determination of active compositions in Chrysanthemum morifolium (Hangbaiju) is of great value for producers and consumers. Hyperspectral imaging as a rapid and nondestructive technique was used to determine total polysaccharides and total flavonoids content in Chrysanthemum morifolium. Hyperspectral [...] Read more.
The rapid and nondestructive determination of active compositions in Chrysanthemum morifolium (Hangbaiju) is of great value for producers and consumers. Hyperspectral imaging as a rapid and nondestructive technique was used to determine total polysaccharides and total flavonoids content in Chrysanthemum morifolium. Hyperspectral images of different sizes of Chrysanthemum morifolium flowers were acquired. Pixel-wise spectra within all samples were preprocessed by wavelet transform (WT) followed by standard normal variate (SNV). Partial least squares (PLS) and least squares-support vector machine (LS-SVM) were used to build prediction models using sample average spectra calculated by preprocessed pixel-wise spectra. The LS-SVM model performed better than the PLS models, with the determination of the coefficient of calibration (R2c) and prediction (R2p) being over 0.90 and the residual predictive deviation (RPD) being over 3 for total polysaccharides and total flavonoids content prediction. Prediction maps of total polysaccharides and total flavonoids content in Chrysanthemum morifolium flowers were successfully obtained by LS-SVM models, which exhibited the best performances. The overall results showed that hyperspectral imaging was a promising technique for the rapid and accurate determination of active ingredients in Chrysanthemum morifolium, indicating the great potential to develop an online system for the quality determination of Chrysanthemum morifolium. Full article
Show Figures

Figure 1

Back to TopTop