Fortschritte der anorganischen Chemie seit 1921

Klemm, Wilhelm

doi:10.1002/ange.19250380204

Cited by 2 publications

(3 citation statements)

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“…Yet, it remains poor as compared with the results for other elements and indicates an unsatisfying repeatability for fluorine analyses. The finding of increasing fluorescence intensities for fluorine is confirmed by less comprehensive fluorine analyses of another soil, eight granites, several slags, kaolin, lime and gypsum; among them, there are three certified reference materials (GM, KH, KK, for fluorine concentrations see).…”

Section: Resultsmentioning

confidence: 84%

“…The basic approach of this study did not require sample materials with distinct or exactly known element concentrations but rather typical matrices. An in‐house standard soil sample (BO‐A) with 840 mg/kg F, determined by potentiometry subsequently to digestion after Klemm, was chosen. Two certified reference materials, Basalt Ribeiráo Preto (BRP‐1) and Canadian stream sediment (STSD‐1) with 490 µg/g F and 950 µg/g F, respectively, were used for the experiments as well as glassy sand SpS (6‐1‐0‐2) with fluorine below the detection limit as additive for dissolution purposes.…”

Section: Methodsmentioning

confidence: 99%

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X‐ray‐induced alteration of specimens as crucial obstacle in XRF spectrometry of fluorine in rocks and soils

Pleßow

2012

X-Ray Spectrometry

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Occasionally suggested yet rarely performed X-ray fluorescence (XRF) spectrometry of fluorine seems to fail systematically in yielding reliable quantitative results for rocks and soils. Repeated analyses reveal continuously drifting fluorescence intensities for fluorine, boron and chlorine. Typically, an increase, but in few cases also a decrease, over X-ray exposure time is observed. For instance, fluorine concentrations in a soil standard appear to increase steadily from below the detection limit in the first run to nearly 850 mg/kg F more than 10 h later in the last. In contrast, cryolite is characterised by drastically decreasing intensities for fluorine. Although fluorescence intensities may be affected by preparation methods, specimen surface conditions and dynamic contamination, it is shown that none of these influencing factors is responsible for the observed trends. In fact, there is evidence that X-radiation impact mobilises fluorine, boron and chlorine. Diffusion of radiolysis products towards the specimen's surface as well as the kinetics of adsorption and desorption or chemical reactions are believed to control the analyte concentration in the analysed layer decisively. Furthermore, during analysis, the latter is altered by considerable losses of binder or fluxif applicable thus enhancing XRF intensities of boron and fluorine because of reduced absorption. In any case, signal stability appears to be limited by insufficient sample and specimen stability. It is concluded that for many soil and rock samples, XRF spectrometry is inappropriate to quantify fluorine, although the crucial obstacle is neither the analytical method nor the spectrometer sensu strictu.

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Section: Resultsmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 99%

X‐ray‐induced alteration of specimens as crucial obstacle in XRF spectrometry of fluorine in rocks and soils

Pleßow

2012

X-Ray Spectrometry

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“…(e) Males were used because even in the same species, individual enterochromafiin cell counts vary depending on the animals' sex. A greater number of enterochromaffin cells has been found in the adult female guinea pig than in the male (14)(15)(16)(17). It was pointed out, however, that the enterochromaffin cell count varies with the stage of the estral cycle (17).…”

Section: Methodsmentioning

confidence: 99%