scholarly journals The Use of Right Angle Fluorescence Spectroscopy to Distinguish the Botanical Origin of Greek Common Honey Varieties

2021 ◽  
Vol 11 (9) ◽  
pp. 4047
Author(s):  
Marinos Xagoraris ◽  
Panagiota-Kyriaki Revelou ◽  
Eleftherios Alissandrakis ◽  
Petros A. Tarantilis ◽  
Christos S. Pappas
Keyword(s):  
Fluorescence Spectroscopy ◽  
External Validation ◽  
Three Dimensional ◽  
Excitation Wavelength ◽  
Botanical Origin ◽  
Linear Discriminant ◽  
Classification Score ◽  
Hydroxybenzoic Acids ◽  
Unifloral Honey ◽  
Novel Method

The standardization of the botanical origin of honey reflects the commercial value and quality of honey. Nowadays, most consumers are looking for a unifloral honey. The aim of the present study was to develop a novel method for honey classification using chemometric models based on phenolic compounds analyzed with right angle fluorescence spectroscopy, coupled with stepwise linear discriminant analysis (LDA). The deconstructed spectrum from three-dimensional-emission excitation matrix (3D-EEM) spectra provided a correct classification score of 94.9% calibration and cross-validation at an excitation wavelength (λex) of 330 nm. Subsequently, a score of 81.4% and 79.7%, respectively, at an excitation wavelength (λex) of 360 nm was achieved. Each chemometric model confirmed its power through the external validation with a score of 82.1% for both. Differentiation could be correlated with hydroxycinnamic and hydroxybenzoic acids, which absorb in this region of the spectrum. Fluorescence spectroscopy constitutes a rapid and sensitive technique, which, when combined with the stepwise algorithm and LDA method, can be used as a reliable and predictive authentication tool for honey. This study indicates that the developed methodology is a promising technique for determination of the botanical origin of common Greek honey varieties. Our long-term ambition is to support producers and suppliers to remain in a competitive national and international market.

IDENTIFICATION OF PETROLEUM OILS BY FLUORESCENCE SPECTROSCOPY

1975 ◽  
Vol 1975 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Uwe Frank
Keyword(s):  
Fluorescence Spectroscopy ◽  
Solvent Effects ◽  
Fluorescence Spectra ◽  
Three Dimensional ◽  
Excitation Wavelength ◽  
Dimensional System ◽  
Identification Methods ◽  
20 Nm ◽  
Three Dimensional System ◽  
Petroleum Oils

ABSTRACT A simple and rapid method for the identification of weathered petroleum oils (passive tagging) by fluorescence spectroscopy is described. The approach used takes advantage of the three-dimensional character of the oil fluorescence spectra. Oil identification methods of other investigators that use fluorescence spectroscopy are also reviewed within the context of the three-dimensional system. Our method involves excitation of the oils at 15 wavelengths, between 220–500 nanometers (nm), at 20-nm intervals. The emission monochromator is rapidly scanned at each excitation wavelength to obtain an emission spectrum. The maximum emission intensities are then plotted versus the excitation wavelengths to derive silhouette profiles. These are used as fingerprints for passive tagging petroleum oils. The influence of weathering, quenching, and solvent effects on our method are also examined.

scholarly journals RIGHT-ANGLE FLUORESCENCE SPECTROSCOPY FOR DIFFERENTIATION OF DISTILLED ALCOHOLIC BEVERAGES

2013 ◽  
Vol 12 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Veronika Uríčková ◽  
Jana Sádecká ◽  
Pavel Májek
Keyword(s):  
Fluorescence Spectroscopy ◽  
Emission Spectra ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Alcoholic Beverages ◽  
Front Face ◽  
Excitation Wavelength ◽  
Spectroscopic Techniques ◽  
Excitation Spectra ◽  
Linear Discriminant

Abstract Total luminescence and synchronous scanning fluorescence spectroscopic techniques were investigated for differentiating brandies from mixed wine spirits. The studies were performed on 16 brandies from 3 different producers and 30 mixed wine spirits from 5 different producers. Differentiation between samples was accomplished by multivariate data analysis methods (principal component analysis, hierarchical cluster analysis, and linear discriminant analysis). Correct classification was obtained using emission spectra (400-650 nm) recorded at excitation wavelength 390 nm, excitation spectra (225-460 nm) obtained at emission wavelength 470 nm and synchronous fluorescence spectra (200-700 nm) collected at wavelength interval 80 nm. These results indicate that right-angle fluorescence spectroscopy offers a promising approach for the authentication of brandies as neither sample preparation nor special qualification of the personnel are required, and data acquisition and analysis are relatively simple when compared to front-face technique.

scholarly journals SPME-GC-MS and FTIR-ATR Spectroscopic Study as a Tool for Unifloral Common Greek Honeys’ Botanical Origin Identification

2021 ◽  
Vol 11 (7) ◽  
pp. 3159
Author(s):  
Marinos Xagoraris ◽  
Panagiota-Kyriaki Revelou ◽  
Stela Dedegkika ◽  
Charalabos D. Kanakis ◽  
George K. Papadopoulos ◽  
...  
Keyword(s):  
External Validation ◽  
Statistical Technique ◽  
Attenuated Total Reflection ◽  
Nonanoic Acid ◽  
Spectroscopic Techniques ◽  
Botanical Origin ◽  
Standard Samples ◽  
Internal Validation ◽  
Linear Discriminant ◽  
Origin Identification

Among the variants of Greek honey, the most commonly available are pine, fir, thyme, and citrus honey. Samples of the above kinds of honey, identified according to European and Greek legislation, were studied using gas chromatography coupled with mass spectrometry (GC-MS) and the attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic techniques. Two chemometric models were developed based on statistically significant volatile compounds (octane; 2-phenylacetaldehyde; 1-nonanol; methyl 2-hydroxybenzoate; 2-(4-methylcyclohex-3-en-1-yl); nonanoic acid) and the 1390–945 and 847–803 cm−1 spectral regions, mainly vibrations of fructose and glucose, combined with the stepwise linear discriminant analysis (stepwise LDA) statistical technique. In total, 85.5% of standard samples, and 82.3% through internal validation and 88.5% through external validation, were identified correctly using the GC-MS-stepwise-LDA chemometric model. The corresponding results for the ATR-FTIR-stepwise-LDA chemometric model were 93.5%, 82.5%, and 84.6%. The double validation (internal, external) enhances the robustness of the proposed chemometric models. The developed models are considered statistically equivalent, but FTIR spectroscopy is simple, rapid, and more economical.

Identification of Oil Contaminants on Polymer Coated Beverage Cans Using Fluorescence Spectroscopy

2003 ◽  
Vol 57 (8) ◽  
pp. 1042-1048 ◽  
Author(s):  
Michael Malecha ◽  
Conrad Bessant ◽  
Selwayan Saini
Keyword(s):  
Fluorescence Spectroscopy ◽  
Fiber Optics ◽  
Fiber Optic ◽  
Indirect Measurements ◽  
Linear Discriminant ◽  
Alternative Approach ◽  
Novel Method ◽  
Components Analysis ◽  
Low Sensitivity ◽  
Detection And Recognition

In a recent publication we introduced a novel method for detection of impurities on beverage can surfaces using Raman spectroscopy. While investigating the technique, limitations emerged due to the low sensitivity of Raman scatter. This is a particular problem with the largest contributor of impurities in beverage cans: lubricants employed in the manufacturing process. This paper presents an alternative approach, using the more sensitive technique of fluorescence spectroscopy to tackle the same problem. Measurements using fluorescence spectroscopy were conducted indirectly in a cuvette as well as directly on a can surface with the aid of fiber optics. The chemometrics methods of linear discriminant analysis (LDA) and principal components analysis (PCA) were used to classify acquired spectra as belonging to one of the 16 investigated lubricants. Fiber-optic scans revealed that a successful detection and recognition of lubricant is possible down to a volume of 0.5 μL deposited on the can surface. Contaminant detection was possible at even lower levels down to 0.01 μL, but reliable identification proved difficult at such low volumes. Indirect measurements of lubricants dissolved in cyclohexane yielded the lowest detection limits between 1–0.1 ppb.

Controllable Electrochemical Synthesis of Ag Hierarchical Micro/Nanostructures with High SERS-Activity

NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050043
Author(s):  
Huayu Zhou ◽  
Jingjing Wang ◽  
Qiong Yang ◽  
Menglei Chen ◽  
Changsheng Song ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Current System ◽  
Three Dimensional ◽  
Constant Current ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Mixed Solution ◽  
Raman Enhancement ◽  
One Step

We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.

scholarly journals Homogeneous 2D and 3D alignment of cardiomyocyte in dilated cardiomyopathy revealed by intravital heart imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoshi Masuyama ◽  
Tomoaki Higo ◽  
Jong-Kook Lee ◽  
Ryohei Matsuura ◽  
Ian Jones ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Three Dimensional ◽  
Single Layer ◽  
Specific Pattern ◽  
Two Dimensional ◽  
Heart Imaging ◽  
Novel Method ◽  
2D And 3D

AbstractIn contrast to hypertrophic cardiomyopathy, there has been reported no specific pattern of cardiomyocyte array in dilated cardiomyopathy (DCM), partially because lack of alignment assessment in a three-dimensional (3D) manner. Here we have established a novel method to evaluate cardiomyocyte alignment in 3D using intravital heart imaging and demonstrated homogeneous alignment in DCM mice. Whilst cardiomyocytes of control mice changed their alignment by every layer in 3D and position twistedly even in a single layer, termed myocyte twist, cardiomyocytes of DCM mice aligned homogeneously both in two-dimensional (2D) and in 3D and lost myocyte twist. Manipulation of cultured cardiomyocyte toward homogeneously aligned increased their contractility, suggesting that homogeneous alignment in DCM mice is due to a sort of alignment remodelling as a way to compensate cardiac dysfunction. Our findings provide the first intravital evidence of cardiomyocyte alignment and will bring new insights into understanding the mechanism of heart failure.

scholarly journals Hemp (Cannabis sativa L.) Seed Protein–EGCG Conjugates: Covalent Bonding and Functional Research

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1618
Author(s):  
Xin-Hui Pang ◽  
Yang Yang ◽  
Xin Bian ◽  
Bing Wang ◽  
Li-Kun Ren ◽  
...  
Keyword(s):  
Particle Size ◽  
Fluorescence Spectroscopy ◽  
Cannabis Sativa ◽  
Three Dimensional ◽  
Epigallocatechin Gallate ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Particle Size Data ◽  
Covalently Bonded ◽  
Covalently Linked

In order to make HPI have a wide application prospect in the food industry, we used EGCG to modify HPI. In this study, we prepared different concentrations (1, 2, 3, 4, and 5 mM) of (−)-epigallocatechin gallate (EGCG) covalently linked to HPI and use methods such as particle size analysis, circular dichroism (CD), and three-dimensional fluorescence spectroscopy to study the changes in the structure and functional properties of HPI after being covalently combined with EGCG. The particle size data indicated that the covalent HPI-EGCG complex was larger than native HPI, and the particle size was mainly distributed at about 200 μm. CD and three-dimensional fluorescence spectroscopy analyses showed that the conformation of the protein was changed by conjugation with EGCG. The β-sheet content decreased from 82.79% to 66.67% after EGCG bound to the protein, and the hydrophobic groups inside the protein were exposed, which increased the hydrophobicity of the protein and changed its conformation. After HPI and 1 mM of EGCG were covalently bonded, the solubility and emulsifying properties of the covalent complex were improved compared with native HPI. These results indicated that HPI-EGCG conjugates can be added in some foods.

scholarly journals BanLec-eGFP Chimera as a Tool for Evaluation of Lectin Binding to High-Mannose Glycans on Microorganisms

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Zorana Lopandić ◽  
Luka Dragačević ◽  
Dragan Popović ◽  
Uros Andjelković ◽  
Rajna Minić ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Lectin Binding ◽  
Three Dimensional ◽  
Data Bank ◽  
Salmonella Typhi ◽  
Excitation Wavelength ◽  
Protein Data Bank Entry ◽  
High Mannose

Fluorescently labeled lectins are useful tools for in vivo and in vitro studies of the structure and function of tissues and various pathogens such as viruses, bacteria, and fungi. For the evaluation of high-mannose glycans present on various glycoproteins, a three-dimensional (3D) model of the chimera was designed from the crystal structures of recombinant banana lectin (BanLec, Protein Data Bank entry (PDB): 5EXG) and an enhanced green fluorescent protein (eGFP, PDB 4EUL) by applying molecular modeling and molecular mechanics and expressed in Escherichia coli. BanLec-eGFP, produced as a soluble cytosolic protein of about 42 kDa, revealed β-sheets (41%) as the predominant secondary structures, with the emission peak maximum detected at 509 nm (excitation wavelength 488 nm). More than 65% of the primary structure was confirmed by mass spectrometry. Competitive BanLec-eGFP binding to high mannose glycans of the influenza vaccine (Vaxigrip®) was shown in a fluorescence-linked lectin sorbent assay (FLLSA) with monosaccharides (mannose and glucose) and wild type BanLec and H84T BanLec mutant. BanLec-eGFP exhibited binding to mannose residues on different strains of Salmonella in flow cytometry, with especially pronounced binding to a Salmonella Typhi clinical isolate. BanLec-eGFP can be a useful tool for screening high-mannose glycosylation sites on different microorganisms.

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