Identification and quantification of valuable plant substances by IR and Raman spectroscopy

The potential energy surface of curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] was explored with the DFT correlation functional B3LYP method using 6-311G* basis. The single-point calculations were performed at levels up to B3LYP/6-311++G**//B3LYP/6-311G*. All isomers were located and relative energies determined. According to the calculation the planar enol form is more stable than the nonplanar diketo form. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. In addition, harmonic vibrational frequencies of the molecule were evaluated theoretically using B3LYP density functional methods. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. Our vibrational data show that in both the solid state and in all studied solutions curcumin exists in the enol form. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

DFT and experimental studies of the structure and vibrational spectra of curcumin

Although the physics of Raman spectroscopy and its application to purely chemical problems is long established, it offers a noninvasive, nondestructive, and water-insensitive probe to problems in the life sciences. Starting from the principles of Raman spectroscopy, its advantages, and methods for signal enhancement, the bulk of the review highlights recent applications. Structural investigations of a hormone receptor, testing the biocompatibility of dental implants, probing soil components and plant tissue alkaloids, and localization of single bacteria are just four problems in which Raman spectroscopy offers a solution or complements existing methods.

Raman Spectroscopy—A Prospective Tool in the Life Sciences

the applicationof this technique in this field has grown exponentially.Although this database and the papers from several groupsthat appeared around the same time introduced many peopleto this research field, these were not the first applications ofRaman microspectroscopy in art analysis. In 1979 Dhamelin-court et al.

A decade of raman spectroscopy in art and archaeology

On the sustainability of lithium ion battery industry – A review and perspective

Non-destructive NIR-FT-Raman spectroscopy of plant and animal tissues, of food and works of art.

New approaches for acceleration of cloud point extraction of Rh, Pd and Pt by microwave and ultrasound irradiation have been investigated. 2-Mercaptobenzothiazole and Triton X-100 were used as ligand and non-ionic surfactant, respectively. Microwave irradiation substantially increased the procedure efficiency. In contrast no significant effect was observed when a micellar solution was treated with ultrasound energy. The acceleration of complex formation reactions by reducing agents (KI and SnCl2) has also been studied. The use of SnCl2 was a prerequisite for quantitative extraction of Rh. Since the extraction kinetics of platinum depends on its oxidation state and presence of Pd, the addition of SnCl2 equalized the platinum extraction behavior. For the first time the whole cloud point procedure was successively accomplished in a microwave system. 10 min of irradiation were sufficient for gravimetrical phase separation and quantitative extraction of platinum group metals. As a result the procedure time was shortened by a factor of 9 in comparison to conventional hot plate cloud point extraction. The surfactant-rich phase was analyzed after dilution with 1 M HCl by continuous nebulization to ICP-MS. Quantitative recoveries and good plasma tolerance were reported. Detection limits of 1 ng.l−1 (Rh), 5 ng.l−1 (Pd), and 6 ng.l−1 (Pt) were achieved regarding a preconcentration factor of 8. The microwave-assisted cloud point extraction has been successfully applied for simultaneous determination of trace amounts of platinum group metals in pharmaceutical products (Tritace, Vivace, Laprilen and Enalapril).

Microwave-assisted cloud point extraction of Rh, Pd and Pt with 2-mercaptobenzothiazole as preconcentration procedure prior to ICP-MS analysis of pharmaceutical products

Non-destructive analysis of natural substances in plants as well as of old dyed textiles by Raman spectroscopy has not been possible using conventional techniques. Exciting lines from the visible part of the spectrum produced photochemical and thermal decomposition of the objects as well as strong fluorescence. Using Nd:YAG laser excitation at 1064 nm together with a special sample arrangement and interferometric recording, various polyacetylenes in Aethusa cynapium and in chamomile (Chamomilla recutita) and the main valuable substances in gentian species (Gentiana lutea and G. punctata), curcuma roots (Curcuma longa), cinnamon (Cinnamomum zeylanicum), fennel (Foeniculum vulgare), clove (Caryophyllus aromaticus), and ginger (Zingiber officinale) were analyzed non-destructively and discussed in comparison with the corresponding pure standard compounds. We further analyzed non-destructively the FT Raman spectra of collections of historical textiles and lakes used for dyeing. It is possible to distinguish the main dye component non-destructively by using Raman bands.

Non-destructive NIR-FT-Raman analyses in practice. Part 1. Analyses of plants and historic textiles

Raman spectroscopic study of some chalcopyrite xanthate flotation products

http://web.uni-plovdiv.bg/plamenpenchev/art09.pdf

G. N. Andreev

Papers

Non-destructive NIR-FT-Raman spectroscopy of plant and animal tissues, of food and works of art.

Microwave-assisted cloud point extraction of Rh, Pd and Pt with 2-mercaptobenzothiazole as preconcentration procedure prior to ICP-MS analysis of pharmaceutical products

Non-destructive NIR-FT-Raman analyses in practice. Part 1. Analyses of plants and historic textiles

Raman spectroscopic study of some chalcopyrite xanthate flotation products

Automatic classification of infrared spectra using a set of improved expert-based features