Search Results

You are looking at 21 - 30 of 360 items for :

  • "fingerprint" x
  • All content x
Clear All

Abstract  

This paper reports on initial efforts for uranium isotopic analysis using gamma-rays and X-ray fluorescence coincidence. In this study, a gamma–gamma coincidence spectrometry was developed. The spectrometry consists of two NaI(Tl) scintillators and XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The developed spectrometry was optimized according to the considerations of output count rate and gamma peak energy resolution. It has been demonstrated that the spectrometry provides an effective method of assessing the content of uranium isotopes for nuclear materials. The main advantages of this approach over the conventional gamma spectrometry include the fact that 235U enrichment can be graphically characterized by its unique coincidence “fingerprints”. The method could be further developed for fast uranium isotope verification with an established gamma–gamma coincidence spectral imaging library by various nuclear materials.

Restricted access

Summary

To control the quality of Euonymus fortunei (Turcz.) Hand.-Mazz., a simple and reliable method of high-performance liquid chromatography (HPLC) coupled with photodiode array detector (PAD) was developed for both fingerprint analysis and quantitative determination. Four representative flavonoids, namely, kaempferol-3-O-β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranosyl-7-O-β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranoside (I), kaempferol-3,7-O-α-dirhamnopyranoside (II), apigenin-7-O-β-D-glucopyranoside (III), and kaempferol-3-(4″-O-acetyl)-O-α-L-rhamnopyranoside-7-O-α-L-r hamnopyranoside (IV) isolated from E. fortunei, were used as reference compounds and simultaneously determined by the validated HPLC method. The unique properties of the chromatographic fingerprint were validated by analyzing 11 batches of E. fortunei, E. japonicus, E. laxiflorus, E. myrianthus, and E. hamiltonianus samples. Our results revealed that the chromatographic fingerprint combined with similarity measurement could efficiently identify and distinguish E. fortunei from the other investigated Euonymus species.

Restricted access

Seven different Scutellaria species were analyzed using the extraction procedure (Soxhlet apparatus, dichloromethane, and methanol as solvents) and thin-layer chromatography method. Selected standards of flavonoids and phenolic acids (caffeic acid, chlorogenic acid, ferulic acid, baicalein, wogonin, baicalin, chrysin, quercetin, scutellarin, hesperetin, hesperidin, apigenin, luteolin, rutin, and kaempferol) were separated using silica gel thin-layer chromatography (TLC) plates with the mobile phase consisting of ethyl acetate—toluene—formic acid (5:4.9:0.1, v/v) for dichloromethane and methanolic extracts. Dichloromethane extracts were also developed using cyanopropyl-bonded silica gel with the following mobile phases: propan-2-ol—n-heptane—formic acid (5:4.9:0.1, v/v) and methanol—water—formic acid (6:3.9:0.1, v/v), and after drying, they were sprayed using the anisaldehyde reagent. In the case of methanolic extracts, the same non-aqueous eluent was used and the aqueous eluent consisting of methanol—water—formic acid (4:5.9:0.1, v/v). The presence of selected standards in Scutellaria species was confirmed. The similarities between the obtained fingerprint chromatograms were performed using chemometric methods, the similarity coefficients (Pearson’s correlation coefficient, determination coefficient, and congruence coefficient), distance indices (Euclidean distance, Manhattan distance, and Chebyshev’s distance), and multi-scale structural similarity (MS-SSIM).

Restricted access

High-performance thin-layer chromatography (HPTLC) proved to be a well-suited method for characterization and assignment of polysaccharide-based biopolymers in all types of plant-derived or modified thickening agents, stabilizers, or hydrocolloids on the market. The newly developed HPTLC method allows for differentiation of the polysaccharides due to its characteristic fingerprint. It is a highly effective, rapid, and cost-saving alternative or complementary method to current official methods. After a reduced sample preparation including methanolysis of the polysaccharides, up to 21 samples were separated on HPTLC silica gel plates simultaneously under identical conditions in 20 min. For determination of the methylated monomeric units in the UV-VIS range, a selective postchromatographic derivatization was performed using the aniline diphenylamine o-phosphoric acid reagent. Via spectra recording, the maximum wavelengths were obtained and absorption measurement was performed at various wavelengths showing the potential for quantification based on selected marker compounds. The limit of detection (LOD) of the methylated monomeric units was by a factor of 5 worse if compared to the non-methylated monomeric units, but this was not critical for analysis.

Restricted access

Ten methanolic extracts of selected Cirsium species were analyzed using two-dimensional thin-layer chromatography (2D-TLC) system with octadecyl reversed-phase (RP-18) chromatographic plate as the stationary phase and two eluents: nonaqueous, consisting of 2-butanone‒toluene‒acetic acid (4.5:5:0.5, v/v) used in the first direction of developing, and aqueous, consisting of methanol—water—formic acid (4:5:1, v/v) used in the second direction. The Naturstoff reagent was used for the derivatization of some phenolic compounds. Five selected standards were analyzed under the same chromatographic conditions, and their retention factor values were used for the confirmation of their presence on selected Cirsium chromatograms. Photographs of ten chromatograms were treated using the ImageJ program. 2D-TLC analysis was also performed to obtain the fingerprint chromatographic profiles of the studied methanolic extracts. The experimental data were objected to principal component analysis (PCA), and the PC2 vs. PC3 graphs were created. Based on the PCA results, the similarity between the selected Cirsium species was confirmed.

Restricted access

. Ristivojević , J. Trifković , I. Vovk , D. Milojković-Opsenica , Comparative Study Of Different Approaches for Multivariate Image Analysis in HPTLC Fingerprinting of Plant Resin Extracts , 21st International Symposium on Separation Sciences

Restricted access

The flavonoid and triterpenoid soyasaponin content of the aerial parts of Desmodium adscendens from four geographical origins of Africa (Ghana, Nigeria, Sierra Leone, and Togo) has been studied by planar chromatography, because the species is supposed to have hepato-protective activity. Comparative study of these compounds revealed the presence of flavonoids such as vitexine and isovitexine and soyasaponins such as soyasaponin I. The study proves the suitability of TLC analysis of soyasaponins for fingerprinting of this genus.

Restricted access

A Ph. Eur. herbal drug monograph requires for identification testing besides macroscopic (A) and microscopic (B) evaluation a thin-layer chromatography (TLC) fingerprint, prescribed as identification testing in subsection C. The main active constituents of Cassia senna L. and Cassia angustifolia Vahl are the dianthrone glucosides (mainly sennoside A and B). Therefore, this study presents a high-performance thin-layer chromatography (HPTLC) method which uses the sennosides as characteristic constituents. The presented method results in a fast and simple fingerprint with characteristic yellow fluorescence for the sennosides due to derivatization with a potassium hydroxide solution. The use of a senna herbal drug dry extract as system suitability test (SST) allows for a cost-effective test control. The resolution of the sennosides zones is dependent on the extractives concentration. An overload of the analytes leads to tailing (u-shaped form) and broadening as well as change in the retardation factor (R F). The presented method is a suitable fingerprint method for Ph. Eur. conform identification C.

Restricted access

Summary

The stems of Uncaria rhynchophylla (Miq.) ex Havil have a long history of use in traditional Chinese medicine to treat diseases and improve health. There is evident evidence that alkaloids constituents are mainly responsible for the beneficial effects of this plant medicine. The amounts of the major bioactive alkaloids in this plant vary widely with species, habitat, and as such, and establishment of a high-performance liquid chromatography (HPLC) fingerprint for quality control of this herbal medicine is of particular importance. The most alkaloids are used for medicine treatment and research. On the basis of the chromatographic data, a consistent HPLC fingerprint pattern containing 15 common peaks was obtained. Among these common peaks, four were identified as rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxeine. On the basis of this HPLC fingerprint and principal-components analysis, the quality of fifteen samples from different producing areas of China was objectively assessed. To summarize, the data described in this study offer valuable information for quality control and proper use of U. rhynchophylla (Miq.) ex Havil.

Restricted access

Summary

Identification of closely related plant species is not a trivial task, and is often difficult on the basis of morphological or anatomical features. To differentiate among analyzed species, a chromatographic fingerprint is usually constructed. This is not easy for very complex samples, however, especially those containing substances spanning a wide polarity range. In such circumstances more than one fingerprint is constructed, e.g. one for polar and the other for apolar constituents. In this paper a new method has been used for resolution of a mixture of 17 coumarins and flavonoids and, subsequently, construction of a fingerprint of closely related species belonging to the Peucedanum genus. This is the first time multidimensional planar chromatography has been applied for such purpose. Distinctive fingerprints are produced for every analyzed plant species, without the need to construct two fingerprints and without the application of more sophisticated multidimensional methods (e.g. hyphenation of HPLC and TLC, HPLC-MS, etc).

Restricted access