scholarly journals Observation of Climacteric-Like Behavior of Citrus Leaves Using Fluorescence Spectroscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Caio B. Wetterich ◽  
Emery C. Lins ◽  
José Belasque ◽  
Luis G. Marcassa
Keyword(s):  
Chlorophyll Fluorescence ◽  
Sample Preparation ◽  
Fluorescence Spectroscopy ◽  
Time Evolution ◽  
Diagnostic Technique ◽  
Ethylene Evolution ◽  
Complex Sample ◽  
Citrus Leaves

Observation of climacteric-like behavior in citrus leaves depends on the detection of ethylene. However, such detection requires a gas chromatographer and complex sample preparation procedures. In this work, fluorescence spectroscopy was investigated as a diagnostic technique for climacteric-like behavior in citrus leaves. Our results indicate that the chlorophyll fluorescence presents a time evolution consistent with the ethylene evolution. Therefore, fluorescence spectroscopy may be used to observe the climacteric-like behavior in citrus leaves.

scholarly journals Rapid Method Using Two Microbial Enzymes for Detection of l-Abrine in Food as a Marker for the Toxic Protein Abrin

2014 ◽  
Vol 81 (5) ◽  
pp. 1610-1615 ◽  
Author(s):  
Anthony G. Dodge ◽  
Kelvin Carrasquillo ◽  
Luis Rivera ◽  
Lei Xu ◽  
Lawrence P. Wackett ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Visual Detection ◽  
Food Samples ◽  
Content Type ◽  
Toxic Protein ◽  
Beverage Samples ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Complex Sample ◽  
Food And Beverage

ABSTRACTAbrin is a toxic protein produced by the ornamental plantAbrus precatorius, and it is of concern as a biothreat agent. The small coextracting moleculeN-methyl-l-tryptophan (l-abrine) is specific to members of the genusAbrusand thus can be used as a marker for the presence or ingestion of abrin. Current methods for the detection of abrin orl-abrine in foods and other matrices require complex sample preparation and expensive instrumentation. To develop a fast and portable method for the detection ofl-abrine in beverages and foods, theEscherichia coliproteinsN-methyltryptophan oxidase (MTOX) and tryptophanase were expressed and purified. The two enzymes jointly degradedl-abrine to products that included ammonia and indole, and colorimetric assays for the detection of those analytes in beverage and food samples were evaluated. An indole assay using a modified version of Ehrlich's/Kovac's reagent was more sensitive and less subject to negative interferences from components in the samples than the Berthelot ammonia assay. The two enzymes were added into food and beverage samples spiked withl-abrine, and indole was detected as a degradation product, with the visual lower detection limit being 2.5 to 10.0 μM (∼0.6 to 2.2 ppm)l-abrine in the samples tested. Results could be obtained in as little as 15 min. Sample preparation was limited to pH adjustment of some samples. Visual detection was found to be about as sensitive as detection with a spectrophotometer, especially in milk-based matrices.

Comparison of Three Sample Preparation Techniques for Determination of Organic Bromide and Chloride in Halogenated Lipids by X-Ray Fluorescence Spectroscopy

1980 ◽  
Vol 63 (4) ◽  
pp. 709-712
Author(s):  
Henry B S Conacher ◽  
Rajinder K Chadha ◽  
Gladys Lacroix
Keyword(s):  
Thin Film ◽  
Sample Preparation ◽  
Fluorescence Spectroscopy ◽  
Vegetable Oils ◽  
X Ray ◽  
Thin Film Technique ◽  
High Concentrations ◽  
Preparation Techniques

Abstract Three sample preparation techniques—thin-film, solution, and cellulose pellet—were applied to the determination of bromide in brominated lipids by X-ray fluorescence spectroscopy. Using brominated vegetable oils of known bromide content it was demonstrated that the thin-film technique could result in erroneously high bromide contents, which could also vary with the amount of oil applied, depending on the solvent used. As solutions in hexane, slightly high bromide contents were observed at high concentrations. With the cellulose pellets, bromide contents similar to known values were observed. It was concluded that the cellulose pellet procedure, although more time consuming, and less convenient for ready recovery of sample, was the most suitable for organic bromide determination. Similar results were indicated for chlorinated oils.

Laser dentistry: Root canal diagnostic technique based on ultraviolet-induced fluorescence spectroscopy

1989 ◽  
Vol 9 (4) ◽  
pp. 358-361 ◽  
Author(s):  
Roberto Pini ◽  
Renzo Salimbeni ◽  
Matteo Vannini ◽  
Stefano Cavalieri ◽  
Roberto Barone ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Root Canal ◽  
Diagnostic Technique ◽  
Laser Dentistry

scholarly journals Laser-induced fluorescence spectroscopy for early disease detection in grapefruit plants

2020 ◽  
Vol 19 (5) ◽  
pp. 713-721 ◽  
Author(s):  
M. Saleem ◽  
Babar Manzoor Atta ◽  
Zulfiqar Ali ◽  
M. Bilal
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Spectroscopy ◽  
Laser Induced Fluorescence ◽  
Disease Detection ◽  
Early Disease ◽  
Early Disease Detection

Fluorosensor – Non-destructively measures chlorophyll fluorescence directly from leaves which made possible for early disease detection in plants.

scholarly journals Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Tatjana Dramićanin ◽  
Lea Lenhardt Acković ◽  
Ivana Zeković ◽  
Miroslav D. Dramićanin
Keyword(s):  
Sample Preparation ◽  
Fluorescence Spectroscopy ◽  
Principal Component ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Fluorescence Excitation ◽  
Linear Discriminant ◽  
Excitation Emission Matrices ◽  
Fluorescence Excitation Emission Matrices

Honey is a frequent target of adulteration through inappropriate production practices and origin mislabelling. Current methods for the detection of adulterated honey are time and labor consuming, require highly skilled personnel, and lengthy sample preparation. Fluorescence spectroscopy overcomes such drawbacks, as it is fast and noncontact and requires minimal sample preparation. In this paper, the application of fluorescence spectroscopy coupled with statistical tools for the detection of adulterated honey is demonstrated. For this purpose, fluorescence excitation-emission matrices were measured for 99 samples of different types of natural honey and 15 adulterated honey samples (in 3 technical replicas for each sample). Statistical t-test showed that significant differences between fluorescence of natural and adulterated honey samples exist in 5 spectral regions: (1) excitation: 240–265 nm, emission: 370–495 nm; (2) excitation: 280–320 nm, emission: 390–470 nm; (3) excitation: 260–285 nm, emission: 320–370 nm; (4) excitation: 310–360 nm, emission: 370–470 nm; and (5) excitation: 375–435 nm, emission: 440–520 nm, in which majority of fluorescence comes from the aromatic amino acids, phenolic compounds, and fluorescent Maillard reaction products. Principal component analysis confirmed these findings and showed that 90% of variance in fluorescence is accumulated in the first two principal components, which can be used for the discrimination of fake honey samples. The classification of honey from fluorescence data is demonstrated with a linear discriminant analysis (LDA). When subjected to LDA, total fluorescence intensities of selected spectral regions provided classification of honey (natural or adulterated) with 100% accuracy. In addition, it is demonstrated that intensities of honey emissions in each of these spectral regions may serve as criteria for the discrimination between natural and fake honey.

Nondestructive Evaluation of Anthocyanins in Olive (Olea europaea) Fruits by in Situ Chlorophyll Fluorescence Spectroscopy

2005 ◽  
Vol 53 (5) ◽  
pp. 1354-1363 ◽  
Author(s):  
Giovanni Agati ◽  
Patrizia Pinelli ◽  
Solange Cortés Ebner ◽  
Annalisa Romani ◽  
Aurélie Cartelat ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Spectroscopy ◽  
Nondestructive Evaluation ◽  
Olea Europaea ◽  
Olea Europaéa
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