Showing papers on "Fluorescence spectrometry published in 1970"
TL;DR: Results showed good agreement for a variety of samples, including heather, peat, clover, rye grass, mixed herbage, grain, straw, kale leaf, turnip, hay, silage, oak leaf and draff, indicating that almost all samples of vegetable origin can be reliably analysed for these seven elements by the proposed X-ray method.
Abstract: A method capable of wide application to the analysis of plant and faecal materials involving X-ray fluorescence spectrometry for magnesium, aluminium, silicon, phosphorus, sulphur, potassium and calcium is described. Ball milling the material for 10 minutes is sufficient to eliminate particle-size effects in samples diluted 1 + 1 with cellulose when compressed into discs. Inter-element effects are overcome by the use of correction lines and calibration for all elements is carried out with synthetic standards made by incremental addition.Most of the elements can be determined with coefficients of variation within ±1·0 per cent. at low concentrations. Results covering wide concentration ranges, obtained by X-ray and chemical methods, showed good agreement for a variety of samples, including heather, peat, clover, rye grass, mixed herbage, grain, straw, kale leaf, turnip, hay, silage, oak leaf and draff, thus indicating that almost all samples of vegetable origin can be reliably analysed for these seven elements by the proposed X-ray method.
42 citations
TL;DR: In this paper, the acid-base equilibria of the trans-1,2-dipyridylethylenes have been studied by absorption and fluorescence spectrometry.
17 citations
TL;DR: Evidence for porphyrins was obtained in the Apollo 11 bulk sample of lunar dust by fluorescence spectrometry and analytical demetallation, and the similarity of results suggests that most if not all of the indicated p Morphyrin aggregate of the lunar sample probably was synthesized from rocket fuel during the landing of the moon module.
Abstract: Evidence for porphyrins was obtained in the Apollo 11 bulk sample of lunar dust by fluorescence spectrometry and analytical demetallation. The indicated porphyrins showed major fluorescence excitation at 390 nanometers. Abundance was about 10(-10) gram of porphyrin per gram of dust. Similar pigments were found in exhaust products from tests of a lunar descent engine. The similarity of results suggests that most if not all of the indicated porphyrin aggregate of the lunar sample probably was synthesized from rocket fuel during the landing of the lunar module. These compounds may be the product of a novel high-temperature synthesis of cosmochemical interest.
15 citations
TL;DR: In this paper, an X-ray spectrometric scan of a longitudinally sliced drill core showed a close correlation between rare-earth abundances and appropriate minerals, and a calibration was established between the fractions of Ce and Nd and their abundances determined by mass spectrometry.
12 citations
TL;DR: In this article, a graphite cell system with both continuum and line sources for excitation was used for atomic absorption (AA) and atomic fluorescence (AF) spectrometry.
Abstract: The atomic concentration available for excitation in atomic absorption (AA) and atomic fluorescence (AF) spectrometry can be increased by maintaining a low concentration of species, such as O, OH, etc., to minimize compound formation and maintaining a fairly low temperature to minimize ionization. An effective means of accomplishing this is to use a graphite furnace (at a temperature of about 2000°K). Such a furnace if flushed with argon provides a nearly ideal environment for atomization of the sample. L'vov has used such a system for AA. More recently Massman, and Woodriff, have described similar systems for AA and have obtained excellent senstivities for elements normally difficult to atomize in flames, e.g. Al and Sn. Massman also used a graphite furnace with hollow cathode discharge tube sources for AF and again obtained good sensitivities for several elements even though his sources were of low intensities. The major difficulties encountered in using graphite cells have been poor reproducibility in sampling and the presence of high background. A theoretical comparison of the graphite cell and the flame cell for analytical spectrometry is given. Also emission, absorption and fluorescence spectrometry are compared with respect to radiance levels. As a result of the theoretical comparison, the optimum method for trace element analysis would seem to be atomic fluorescence with a graphite cell. We are using a unique graphite cell system with both continuum and line sources for excitation. We are modulating the exciting radiation and using either a synchronous photon counting or a lock-in amplifier. The sample solution is introduced into the graphite cell via a hypodermic syringe or via a nebulizer. An argon flush is used to minimize oxidation of the graphite.
12 citations
01 Jan 1970
TL;DR: Apollo 11 lunar fine porphyrin-like pigments content demonstrated by fluorescence spectrometry and analytical demetallation, suggesting rocket exhaust source as mentioned in this paper, suggests the source of the pigments.
Abstract: Apollo 11 lunar fines porphyrin-like pigments content demonstrated by fluorescence spectrometry and analytical demetallation, suggesting rocket exhaust source
9 citations
15 Aug 1970
TL;DR: In this paper, the presence of porphyrins in Apollo 11 and 12 soil samples by fluorescence spectrometry and analytical demetallation was determined by using a combination of demetralization and demetrization.
Abstract: Determining presence of porphyrins in Apollo 11 and 12 soil samples by fluorescence spectrometry and analytical demetallation
1 citations