scholarly journals Automatic Discrimination of the Geographical Origins of Milks by Excitation-Emission Fluorescence Spectrometry and Chemometrics

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Lu Xu ◽  
De-Hua Deng ◽  
Chen-Bo Cai ◽  
Hong-Wei Yang
Keyword(s):  
Eastern China ◽  
Emission Spectra ◽  
Fluorescence Spectrometry ◽  
Model Accuracy ◽  
Excitation Spectra ◽  
Quick Method ◽  
Western Yunnan ◽  
Time Required ◽  
Analytical Time ◽  
Total Accuracy

This paper presents the automatic discrimination of geographical origins of milks from Western Yunnan Plateau areas and eastern China by excitation-emission fluorescence spectrometry and chemometrics. Genuine plateau milks (n=60) and milks from eastern China (n=89) are scanned in the regions of 180–300 nm for excitation and 200–800 nm for emission. Different options of data analysis are investigated and compared in terms of their performance in discriminating milks of different geographical origins: (1) two-way partial least squares discriminant analysis (PLSDA) based on excitation and emission spectra, respectively; (2) two-way PLSDA based on fusion of excitation and emission spectra; (3) three-way PLSDA based on excitation-emission matrix spectra. The two-way PLSDA methods with excitation spectra, emission spectra, and fusion of excitation and emission spectra correctly classify 91.3%, 88.6%, and 95.3% of the milk samples, respectively; while the total accuracy of three-way PLSDA is 96.0%. The results demonstrate the two-way data combining excitation and emission spectra are sufficient to characterize and identify the plateau milks. Considering both model accuracy and the analytical time required, two-way PLS-DA with fusion of excitation and emission spectra is recommended as a reliable and quick method to discriminate plateau milks from ordinary milks.

Fourier Transform Fluorescence Spectrometry

1988 ◽  
Vol 42 (8) ◽  
pp. 1563-1566 ◽  
Author(s):  
B. Hlivko ◽  
H. Hong ◽  
R. R. Williams
Keyword(s):  
Fourier Transform ◽  
Fluorescence Polarization ◽  
Fluorescence Spectra ◽  
Laser Excitation ◽  
Emission Spectra ◽  
Laser Fluorescence ◽  
Fluorescence Spectrometry ◽  
Excitation Spectra ◽  
Polarization Spectra ◽  
Monochromatic Source

A variety of fluorescence spectra have been measured interferometrically, demonstrating the feasibility of Fourier Transform Fluorescence Spectrometry (FT-FS). Emission spectra have been measured with the use of a monochromatic source and an interferometer as the emission selector. Excitation spectra have been measured with the use of a multi-line laser. Fluorescence polarization spectra have also been recorded with the use of laser excitation. The analytical characteristics of working curves are discussed.

scholarly journals Excitation versus Emission Spectra as a Means to Examine Selective Fluorescence Quenching Agents

1992 ◽  
Vol 46 (9) ◽  
pp. 1388-1392 ◽  
Author(s):  
Sheryl A. Tucker ◽  
William E. Acree
Keyword(s):  
Fluorescence Quenching ◽  
Spectral Data ◽  
Emission Spectra ◽  
Data File ◽  
Excitation Spectra

To ascertain whether fluorescence quenching is best studied with the use of excitation or emission spectra, and to expand our existing PAH spectral data file, we have recorded excitation spectra of benzo[b]perylene, dibenzo[hi,wx]heptacene, tetrabenzo[de,hi,mn,qr]naphthacene, perylene, benzo[a]fluoranthene, benzo[def]indeno[1,2,3hi]chrysene, naphtho[2,1a]fluoranthene, naphtho[2,3b]fluoranthene, benzo[k]fluoranthene, 2-azapyrene, naphtho[8,1,2hij]pyreno[9,10,1def]phthalazine, indeno[1,-2,3ij]isoquinoline, benzo(lmn][3,8]phenanthroline, and 7-methyldibenzo(b,def]chrysene at various nitromethane concentrations. Results of these measurements verify our earlier observations concerning the nitromethane selective quenching rule and further illustrate the importance of considering inner-filtering artifacts in quenching studies.

Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing

2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Organic Additive ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Close Relationship ◽  
Dip Coating Technique

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.

scholarly journals Spectrofluorimetric Determination of Hydrochlorothiazide by a Carbon Dots-Based Probe via Inner Filtering Effect and Resonance Rayleigh Scattering

2022 ◽  
Author(s):  
Ali Ghafarloo ◽  
Reza Sabzi ◽  
Naser Samadi ◽  
Hamed Hamishehkar
Keyword(s):  
Carbon Dots ◽  
Rayleigh Scattering ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Emission Spectra ◽  
Cost Effective ◽  
Inner Filter Effect ◽  
Resonance Rayleigh Scattering ◽  
Excitation Spectra ◽  
One Pot

Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (HCTZ) via inner filter effect (IFE) and resonance Rayleigh scattering (RRS). The as-prepared CDs had wide emission spectra, excitation-dependent emission, high solubility, high stability, and visible fluorescence light with a quantum yield of up to 11%. The absorption of HCTZ overlapped with the excitation spectra of CDs. Therefore, CDs represented excellent quenching due to IFE when HCTZ was gradually added. Furthermore, this fluorescent sensor was successfully used to quantify HCTZ in the linear ranges (0.17-2.50 μg mL-1) with the limit of detection of 0.11 μg mL-1. The sensing system was simple as no surface functionalization was required for CDs, leading to less laborious steps and more cost-effective synthesis. The reaction time was short, i.e., less than 2 min, indicating a simple approach for rapid analysis of HCTZ. By optimizing conditions, successful measurements were carried out on pharmaceutical tablets.

scholarly journals Synthesis and Luminescent Properties of Eu3+/Tb3+ Rare Earth Ions Doped Li2SrSiO4 Phosphors

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaitao Yu ◽  
Lifang Wei ◽  
Jiaqi Shen
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Uv Visible

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

scholarly journals Emission Spectra of Crystal Phosphor BaCl2-Pb

1980 ◽  
Vol 35 (3) ◽  
pp. 308-311 ◽  
Author(s):  
Veneta Tabakova ◽  
Kyncho Kynev
Keyword(s):  
Emission Band ◽  
Emission Spectra ◽  
Barium Chloride ◽  
High Energy ◽  
Low Energy ◽  
Complex Nature ◽  
Excitation Spectra ◽  
Energy Emission ◽  
High Energy Emission ◽  
Effective Excitation

Abstract Emission spectra of Pb2+ centres in barium chloride single crystals have been studied between 4 and 300 K by excitation with different wave lengths. Excitation spectra at 300 K have also been obtained by measuring the emission in the maxima of the shoitwave and longwave bands. The results allow to conclude that the high energy emission band is due to the transition | 3T1u > → | 1A1g > in the activator ion. The more effective excitation of the low energy emission band observed in the shortwave region of the absorption spectrum and the complex nature of both bands are discussed.

Photophysics of Ceramic Luminophores. Zeolite-Based Luminophores of the Types Zn2SiO4: Mn and (CdO)2B2O3: Mn

1989 ◽  
Vol 44 (5) ◽  
pp. 557-559 ◽  
Author(s):  
K. Hesse ◽  
G. Gliemann ◽  
A. Kiss ◽  
P. Kleinschmit ◽  
W. Völker
Keyword(s):  
Emission Spectra ◽  
Structural Defects ◽  
Trap States ◽  
Host Crystal ◽  
Excitation Spectra

The emission spectra (at T = 10 K and 296 K) and the excitation spectra (at T = 295 K) of zeolite-based luminophores of the types Zn2SiO4:Mn and (CdO)2B2O3:Mn show the characteristics of Mn2+ in tetrahedral and octahedral surroundings, respectively, as well as additional features due to impurities and/or structural defects of the host crystal. The ZnSiO4⁻type phosphor exhibits photostimulated emission, which can be assigned to trap states of the silicate host.

Synthesis and luminescence properties of red-emitting K2MgSiO4:Eu3+ phosphors

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744058
Author(s):  
Rong Yang ◽  
Huidong Tang
Keyword(s):  
Decay Curve ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Excitation Spectra ◽  
Red Phosphor ◽  
Light Emitting ◽  
X Ray ◽  
Dipole Interactions ◽  
Near Ultraviolet ◽  
White Light Emitting Diodes

A novel phosphor, K2MgSiO4:Eu[Formula: see text], was synthesized by a solid-state reaction method. The phase formation was checked by X-ray powder diffraction. The photoluminescence excitation, emission spectra, decay curve and CIE coordinates of samples with different Eu[Formula: see text] ion concentrations were investigated in detail. The excitation spectra show a broad wavelength range of 225–470 nm. The K2MgSiO4:Eu[Formula: see text] phosphors exhibit highly red emission peaking at about 616 nm which is assigned to the 5D[Formula: see text]F2 transition of Eu[Formula: see text]ions under the excitation of near-ultraviolet (NUV) (394 nm) light. The critical quenching concentration of Eu[Formula: see text] doped in the K2MgSiO4: Eu[Formula: see text] phosphors was about 10 mol.% and the concentration quenching mechanism was dipole–dipole interactions between Eu[Formula: see text] ions. The results indicate that K2MgSiO4:Eu[Formula: see text] is a potential red phosphor candidate for NUV-pumped white light emitting diodes.

Multicomponent analysis in clinical chemistry by use of rapid scanning fluorescence spectroscopy.

1976 ◽  
Vol 22 (9) ◽  
pp. 1483-1492 ◽  
Author(s):  
I M Warner ◽  
J B Callis ◽  
E R Davidson ◽  
G D Christian
Keyword(s):  
Least Squares ◽  
Clinical Laboratory ◽  
Clinical Chemistry ◽  
Emission Spectra ◽  
Fluorescence Analysis ◽  
Light Level ◽  
Excitation Spectra ◽  
Least Squares Fit ◽  
Reduction Strategies ◽  
Complete Set

Abstract To be useful in the clinical laboratory, multicomponent fluorescence analysis requires both the rapid measurement of the fluorescence intensity at a variety of excitation and emission wavelengths and the unambiguous reduction of the data by efficient algorithms. The Video Fluorometer, which exploits the multi-channel capability of a low-light-level television sensor to simultaneously acquire excitation and emission spectra, can meet the first requirement. For example, a complete set of emission and excitation spectra for perylene can be obtained in less than 2 s at concentrations of 10(-10) mol/liter. To meet the second need, we present two types of data-reduction strategies: (a)a least-squares fit to the data, with use of the spectra of previously determined compounds likely to be present; and (b)a determination of the eigenvalues and eigenvectors fo the fluorescence matrix, from which the number of components and the possible spectra of each can be estimated. Computer simulations of the least-squares fitting algorithms show that five strongly overlapping components can be determined in the presence of noise with an accuracy of better than 5%. Also, a fluorescent sample containing two species with very similar but unknown spectral properties can be resolved to obtain the spectrum of each.

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