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Showing papers on "Fluorescence spectrometry published in 1971"



Journal ArticleDOI
TL;DR: The chemical composition of samples of fry and adult sockeye salmon collected in different areas was characterized by X-ray fluorescence spectrometry and the results indicate that these aquatic organisms possess a chemoprint, a form of natural tag.
Abstract: The chemical composition of samples of fry and adult sockeye salmon (Oncorhynchus nerka) collected in different areas was characterized by X-ray fluorescence spectrometry. Multivariate analysis of the spectra indicate that fish taken from an area possess recognizably distinct chemical compositions. Discriminant functions computed using spectral data were used to classify unknowns successfully. The relative similarity of groups characterized by fluorescence spectrometry is shown by canonical analysis and the nature of the chemical differences is discussed. The results indicate that these aquatic organisms possess a chemoprint, a form of natural tag.

28 citations


Journal ArticleDOI
TL;DR: In this paper, the authors postulate considerable internal conversion 1 S → 0 S with τ ic ≈ 1 −2 × 10 −12 sec, this process correlating with the dielectric relaxation time of water.

19 citations


Journal ArticleDOI
TL;DR: The sedentary female cyst-nematodes feed similarly to aphids and probably excrete a copious sugary waste, which the fungus converts to inert fatty acid thereby preventing local pollution of the rhizosphere, and may also act as a barrier to potential pathogens and predators.
Abstract: The sub-crystalline layer from lemon-shaped females of plant parasitic cyst-nematodes belonging to the genus Heterodera was examined by the scanning electron microscope, X-ray diffraction, X-ray fluorescence spectrometry and mass spectrometry. In H. mani the inner zone of the layer, closely adpressed to the female cuticle and replicating the cuticle pattern, consisted almost entirely of n-tetracosanoic acid. The outer thicker zone consisted of a mixture of the acid and its calcium salt. In H. avenae, the layer had up to 25% hexacosanoic acid in addition; another species, H. trifolii had three aliphatic acids, do-, tetra-, and hexa-cosanoic acids. The outer layer, either from intrinsic shrinkage caused by calcium salts forming or from increasing pressure as the female grows, fractures into pyramidal blocks presenting an irregular polygonal appearance. The fatty acid seems to be produced by an unidentified fungus that metabolises products excreted by the nematode. The sedentary female cyst-nematodes feed similarly to aphids and probably excrete a copious sugary waste, which the fungus converts to inert fatty acid thereby preventing local pollution of the rhizosphere. The layer of acid and its calcium salt may also act as a barrier to potential pathogens and predators. The relationship between the nematode and fungus seems to be symbiotic.

19 citations


01 Jun 1971
TL;DR: In this paper, the authors analyzed sixteen obsidian artifacts from Cerro de las Mesas, Veracruz, and found that the major obsidian source for this site appears to be the Pico de Orizaba locality in Veraca, Mexico.
Abstract: Sixteen obsidian artifacts from Cerro de las Mesas, Veracruz, were analyzed by x-ray fluorescence spectrometry; the major obsidian source for this site appears to be the Pico de Orizaba locality in Veracruz. The results fit into the pattern emerging in which the obsidian industries at major sites are dominated by materials from one particular obsidian source. The major source for Cerro de la Mesas is Pico de Orizaba, for Tres Zapotes it is Zaragoza, Puebla, for San Lorenzo it is Guadalupe Victoria, Puebla, and at La Venta, it is two yet unknown localities. The latter three sites all have substantial Olmec occupation; Cerro de las Mesas is not an Olmec site. -- AATA

13 citations


Journal ArticleDOI
01 Jan 1971-Analyst
TL;DR: A general method for the determination of rare earth elements by X-ray fluorescence spectrometry is described in this paper, where the sample is fused with sodium tetraborate, chromium is added to act as internal control-standard, and the resulting bead is analysed directly.
Abstract: A general method for the determination of rare earth elements by X-ray fluorescence spectrometry is described The sample is fused with sodium tetraborate, chromium is added to act as internal control-standard, and the resulting bead is analysed directly This method overcomes variations in sample form and particle size Individual rare earths can be determined at levels from 0·1 to 100 per cent, and by using the L spectra and a lithium fluoride 220 crystal, line overlap is kept to a minimum

9 citations


Journal ArticleDOI
TL;DR: In this article, the results indicated that emission spectrography with a cobalt internal standard, atomic absorptiometry with a nitrous oxide-acetylene flame, and x-ray fluorescence, both dispersive and nondispersive, are the most reliable instrumental methods.
Abstract: Iron analyses performed on used gas turbine lubricating oil samples by several variations of rotating disk–spark emission spectrography, atomic absorptiometry, and x-ray fluorescence spectrometry are compared with a quantitative wet chemical technique. The results indicate that emission spectrography with a cobalt internal standard, atomic absorptiometry with a nitrous oxide–acetylene flame, and x-ray fluorescence, both dispersive and nondispersive, are the most reliable instrumental methods. The iron contained in the samples exists primarily as particulates 1 μ or less in diameter.

8 citations


Journal ArticleDOI
TL;DR: The results of experiments demonstrated that organisms may possess characteristic elemental compositions that are species specific and multiple discriminant function analysis of the data showed that species may be classified on the basis of their chemical composition with few errors.
Abstract: X-ray fluorescence spectrometry is described as an efficient means of carrying out non-destructive qualitative and quantitative chemical analyses of inorganic substances. A brief review is presented on the way in which this methodology was developed to recognize marked individuals and its application towards determining the geographic origin of organisms using multivariate analysis of the trace element composition of untagged animals. In addition, the results of experiments in which 34 species of invertebrates were compared and different parts of the same organisms irradiated, demonstrated that organisms may possess characteristic elemental compositions that are species specific. Multiple discriminant function analysis of the data showed that species may be classified on the basis of their chemical composition with few errors. Winter and summer growth of molluscan shells were distinguishable by the same method of elemental analysis, and a method for determining the age of organisms is given. Stepwise disc...

7 citations