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- Author or Editor: I. Novák x
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In case of spices or crude drugs of medicinal- and aromatic plant origin, sensory characteristics, especially odour, has great commercial importance. The instrumental sensory analysis the so-called 'electronic nose' has proved to be a significant, new and quick method in chemometry. The sensor signal responses (data recorded by the electronic nose instrument) of the electronic nose were evaluated by statistical methods, including principal component analysis (PCA) and canonical discriminant analysis (CDA) and the combination of these methods by applying the discriminant analysis on the first eight principal components. The aim of this paper is the comparative analysis of the above evaluation methods as data processing tools of the sensor signal response of the electronic nose (chemosensor array). The essential oil of oregano (Origanum vulgare subsp. hirtum) selected line No. 10 was compared to the oil distilled from the selected line No. 11; and dried root samples of lovage (Levisticum officinale) harvested at different times from the two- and three-year-old population, were investigated with electronic nose (NST-3320, AppliedSensor Sweden AB). Principal component analysis, as a first step of the evaluation, did not clearly distinguish either oregano or lovage samples. Further statistical evaluation of the original sensor signal responses of the electronic nose with canonical discriminant analysis improved the separation power of the model. The best separation could be achieved by the combination of the two methods, whereby canonical discriminant analysis was applied to the first eight principal components, which described 99% of the differences. In all cases more than 92%, while in several experiments 100% of cross-validated grouped cases were classified correctly. Based on the results, the application of the electronic nose and the combination of multivariate methods, PCA and CDA, could be an appropriate tool either for identification of cultivar to accelerate selection process or to distinguish crude drugs of different age or different harvesting period.
Abstract
The properties of a composite ion exchanger containing potassium nickel ferrocyanide incorporated in silica gel matrix are described. The sorbent was prepared in the form of spherical beads. For the characterisation of the ion exchanger X-ray diffraction, electron microscopy, IR and Mössbauer spectrometry were used. The sorbent was used for the sorption of radiocesium from model solutions as well as from radioactive waste solutions (NPP Jaslovské Bohunice, Slovakia).
Abstract
A short overview of HPLC column packings is presented. The properties of chromatographic carriers and the possibilities to combine the solid matrices with organic polymeric stationary phases are elucidated in detail. The latest achievements and anticipated future developments in the area are outlined.
Abstract
Inorganic sorbents are often used in separation of metals and radionuclides in radioanalytical application and they were also used in technological scale for separation of radionuclides in cleanup of Three Mile Island NPP. Inorganic sorbents become popular in the last years because no problem with organic contamination, there are stable against radiation, sorption efficiency can be tailor made for selective separation of chosen metal. Contrary to the organic sorbents they have usually lower capacity and chemical stability is limited to narrower pH. Nevertheless of some problems, many good properties of inorganic sorbents make them very attractive for sorption study.
An assemblage of moth species at a suburb of Prague (50°5′11″N,14°18′06″E) was monitored by a highly efficient mercury light trap for 23 years (1967–1976, 1980–1992). Species caught were divided into guilds according to habitat specialisation, and analysed using species richness S , Shannon’s diversity H and evenness J as the response variables, and the individual years of monitoring and effects of mean annual temperature and precipitation as the explanatory variables. Overall, 424 species were recorded: 25 early successional arable land species (43% of all caught individuals), 116 forest species feeding on trees and shrubs, 33 forest species feeding on woodland herbs and lichens, 92 forest-steppe species, 116 grassland species, 28 wetland species, and 14 non-specialized generalists. The diversity of habitat-specialised species responded mainly to land use changes, whereas the diversity of generalists reflected long-term meteorological trends. Species richness of specialists whose habitats in the vicinity of the trap have declined in extent decreased, the numbers of those whose habitats remained intact did not exhibit any particular trend, whereas the numbers of generalists increased, and their diversity positively responded to warming. It is concluded that the habitat specialists and generalists react to environmental changes differently. Non-specialised species appear more sensitive indicators of climate changes than habitat specialists because for the latter the indication of climate changes can be overlaid by changes in habitat use.
Oregano is used worldwide both as spice and crude drug, which is mainly provided by species of Origanum genus. The quality of the product is usually determined by chemical analysis, whereas in food industrial applications sensory tests are also practised. The aim of the present study was a comparison of parallel quality investigations of oregano samples by a new and effective instrumental sensory evaluation method, the “electronic nose”, and by gas-chromatographic and human sensory analysis. The GC analysis of essential oil components revealed mainly differences between plant species (Origanum vulgare subsp. hirtum and Origanum majorana). Main components of the oil of the former taxon are carvacrol and thymol, while those of marjoram are terpinene-4-ol, ?-terpinene and terpinolene. A wholesale oregano sample showing considerable divergence from the other ones with respect to ratios of carvacrol, ß-caryophyllene ß-cubebene and thymol. It was assumed not to belong to ssp. hirtum. The electronic nose analysis, evaluated by PCA, proved to be an appropriate, rapid, non-destructive, reagent-less method for the reliable separation of all of the oregano samples based on their complex aroma features. Assumptions could be made about correlations between separation of samples by the instrumental sensors and proportions of terpenoid compounds of the oil established by GC in some cases only. The varying essential oil content of the samples did not influence the success of instrumental evaluation. The instrumental and human sensory analysis showed similar results: varieties of O. majorana could be well distinguished on the basis of their complex aroma, while their gas-chromatograms did not show characteristic differences. The results call the attention that quality evaluation of drug items of aromatic plants should be oriented in different directions, considering the current utilisation area of the items.
To raise the efficiency of plant regeneration we studied the important and necessary elements of the procedure. The embryogen capacity of 33 various grape genotypes were tested on four different induction media. We successfully obtained anther derived embryogenic calli in 27 genotypes with the range of 1–12%, this is the first reported protocol for embryogenesis from Korai bíbor, Odysseus, Orpheus and Pannon frankos cultivars. Two sorts of sterilization treatments were examined before inducing somatic embryos. For optimisation of grape regeneration system the propagation of calli was attempted in Richter 110 cultivar, there was no any significant differences in the measured values, but CPE medium proved more successful in maintaining embryogenic capacity of callus. We experienced high developmental differences between the propagated embryogenic culture of Richter 110, Teleki 5C and Chardonnay derived from MSNOA liquid medium and from MSE solid medium. Regenerated plants from embryogenic callus were obtained in 21 genotypes, in Chardonnay cultivar CP medium influenced more positively the plant regeneration than the MS/2 medium.
Kinetic analysis of thermogravimetric data
XXVII. Thermal decomposition of some metal and ammonium salts of hexachloroplatinic acid
Nineteen salts of hexachloroplatinic acid with monovalent metals, aromatic and heterocyclic amines and phosphine were obtained and characterized by chemical analysis. The thermal decomposition of these complexes was studied by means of derivatograph and differential scanning calorimetry. The nature of the pyrolysis processes is discussed. From the TG curves, kinetic parameters were derived for different stages of the thermal decompositions.
Abstract
A new approach to dating ancient obsidian artifacts based on the modeling of water diffusion profiles is evaluated using multiple archaeological test cases of known age. Hydrogen profiles from hydrated obsidian surfaces have been collected by secondary ion mass spectrometry (SIMS). The H2O concentration versus depth profiles are modeled and diffusion ages have been produced. SIMS based dates for fourteen obsidian specimens of well-known age, ranging from 300-7000 years old, have been compared with radiocarbon ages. The convergence between the two dating methods is excellent and validates the new dating approach.
Abstract
Solid formulas obtained between furosemide and two β-cyclodextrin derivatives (HP-β-CD and RAMEB) were prepared by different methods and in various ratios (1:1 and 1:2). The inclusion complex formation between the drug and the β-CDs of 1:1 ratio was evaluated by mean of thermal analysis (DSC, TG and EGD). Supplementary techniques, such as X-ray diffraction, were also applied to interpret the results of the thermal study of physically mixed and kneaded products. Both studies demonstrated the formation of inclusion complexes in all samples except the physical mix samples; formation of true inclusion complexes was then possible only when the components were in melted form. The complexation increased the solubility and the rate of dissolution of the drug. RAMEB was found to be a better complexing agent than HP-β-CD; in both ratios it can be selected as a vehicle in furosemide tablet preparations.
