Stability Study of Fat-Soluble Vitamins in Solutions and Biological Samples

AbstractSodium azide is an old poison with toxicity comparable to potassium cyanide. It would seem to be completely forgotten however, between 2000 and 2020, the number of intentional ingestions and murders committed with sodium azide significantly increased. Furthermore, due to its extreme instability, sodium azide is difficult to detect, which poses an additional risk when used to commit a crime. In this study, the epidemiology of sodium azide exposures between 1920 and 2020 was investigated. For the determination the azide concentration in biological samples, a simple, precise and selective headspace gas chromatography method (HS-GC-FID/FID) was developed and fully validated. The limit of quantification was 0.65 µg/mL; and the limit of detection was 0.35 µg/mL; precision and accuracy did not exceed 20%. The stability study was conducted for various biological fluids (urine, bile, blood, gastric content) for 91 days in the refrigerator (4 °C) and the method for stabilization of azide was presented. The addition of a mixture of borax and sodium fluoride (w/w 3:1) to the test tubes can stabilize this poison. The described unique technique of collecting the biological samples poses a great potential for azide detection in clinical and toxicology laboratories even long time after human exposure to this substance.

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An Efficient Statistic for Determining the Diameter of Thin Sectioned Uniform Spheres from Measurements of Biological Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050585 ◽

1974 ◽

Vol 32 ◽

pp. 114-115

Author(s):

W. R. Schucany ◽

G. H. Kelsoe ◽

V. F. Allison

Keyword(s):

Biological Samples ◽

Traditional Method ◽

Cell Types ◽

Accurate Estimation ◽

Morphological Identification ◽

Sectioned Material ◽

Maximal Diameter ◽

Similar Cell

Accurate estimation of the size of spheroid organelles from thin sectioned material is often necessary, as uniquely homogenous populations of organelles such as vessicles, granules, or nuclei often are critically important in the morphological identification of similar cell types. However, the difficulty in obtaining accurate diameter measurements of thin sectioned organelles is well known. This difficulty is due to the extreme tenuity of the sectioned material as compared to the size of the intact organelle. In populations where low variance is suspected the traditional method of diameter estimation has been to measure literally hundreds of profiles and to describe the “largest” as representative of the “approximate maximal diameter”.

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The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101402 ◽

1968 ◽

Vol 26 ◽

pp. 332-333

Author(s):

C. F. Oster

Keyword(s):

Biological Sciences ◽

Epoxy Resin ◽

Cross Sections ◽

Biological Samples ◽

Industrial Applications ◽

Photographic Film ◽

Silver Particles ◽

Thin Sectioning ◽

Embedding Medium

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.

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Artefacts in the x-ray microanalysis of frozen-hydrated biological samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127724 ◽

1987 ◽

Vol 45 ◽

pp. 658-659

Author(s):

Patrick Echlin

Keyword(s):

Electron Scattering ◽

Biological Samples ◽

Fracture Face ◽

Detailed Structure ◽

X Ray ◽

Morphological Appearance ◽

The Poor ◽

Freeze Dried

A number of papers have appeared recently which purport to have carried out x-ray microanalysis on fully frozen hydrated samples. It is important to establish reliable criteria to be certain that a sample is in a fully hydrated state. The morphological appearance of the sample is an obvious parameter because fully hydrated samples lack the detailed structure seen in their freeze dried counterparts. The electron scattering by ice within a frozen-hydrated section and from the surface of a frozen-hydrated fracture face obscures cellular detail. (Fig. 1G and 1H.) However, the morphological appearance alone can be quite deceptive for as Figures 1E and 1F show, parts of frozen-dried samples may also have the poor morphology normally associated with fully hydrated samples. It is only when one examines the x-ray spectra that an assurance can be given that the sample is fully hydrated.

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