Detection reagents used for on-plate identification of organic pesticides in biological samples with preliminary separation by TLC/HPTLC

2020 ◽  
Author(s):  
Qasim Ullah ◽  
Nahid Fatema ◽  
Ali Mohammad
Keyword(s):  
Biological Samples ◽  
Preliminary Separation ◽  
Organic Pesticides

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

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”.

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

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.

Morphometric Analysis of the Hepatocytes from Fish Exposed to Arsenic

1976 ◽  
Vol 34 ◽  
pp. 282-283
Author(s):  
Elsie M. B. Sorensen
Keyword(s):  
Morphometric Analysis ◽  
Arsenic Concentration ◽  
Ultrastructural Changes ◽  
Sodium Arsenate ◽  
Lepomis Cyanellus ◽  
Mammalian Counterpart ◽  
Intracellular Changes ◽  
Green Sunfish ◽  
Organic Pesticides

The detoxification capacity of the liver is well documented for a variety of substances including ethanol, organic pesticides, drugs, and metals. The piscean liver, although less enzymatically active than the mammalian counterpart (1), contains endoplasmic reticulum with an impressive repertoire of oxidizing, reducing, and conjugating abilities (2). Histopathologic changes are kncwn to occur in fish hepatocytes following in vivo exposure to arsenic (3); however, ultrastructural changes have not been reported. This study involved the morphometric analysis of intracellular changes in fish parynchymal hepatocytes and correlation with arsenic concentration in the liver.Green sunfish (Lepomis cyanellus, R.) were exposed to 0, 30, or 60 ppm arsenic (as sodium arsenate) at 20°C for 1, 2, or 3 week intervals before removal of livers for quantification of the arsenic burden (using neutron activation analysis) and morphometric analysis of ultrastructural alterations. Livers were cut into 1 mm cubes for fixation, dehydration, and embedding.

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

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.

Applicability of electrodialysis to the separation of sodium acetate from synthetic alkaline hardwood extract

TAPPI Journal ◽  
2015 ◽  
Vol 14 (11) ◽  
pp. 695-708 ◽  
Author(s):  
RAVIKANT PATIL ◽  
CHI TRUONG ◽  
JOSEPH GENCO ◽  
HEMANT PENDSE ◽  
ADRIAAN VAN HEININGEN
Keyword(s):  
Current Density ◽  
Sodium Sulfate ◽  
Sodium Acetate ◽  
Separation Efficiency ◽  
Feed Concentration ◽  
Initial Concentration ◽  
White Liquor ◽  
Complete Extraction ◽  
Electro Osmosis ◽  
Preliminary Separation

Our objective was to develop a process for recovering acetyl groups from industrial northeast hardwood chips. Extraction experiments showed that the white liquor charge of 6% effective alkali at 50°C and liquor-to-wood ratio of 4:1 leads to the complete extraction of acetyl groups from industrial hardwood chips. Electrodialysis was assessed as a technique for separating and concentrating sodium acetate from synthetic hardwood extract. Preliminary separation experiments using dilute sodium acetate showed that the sodium acetate can be concentrated up to approximately 24% by weight from an initial concentration of about 2% by weight. The effects of current density, feed concentration, electro-osmosis, and osmosis on the separation of sodium acetate were evaluated. Finally, selectivity experiments were performed to study the effect of various components of the white liquor on the separation of sodium acetate. Fully oxidized synthetic white liquor was used in selectivity experiments to avoid deleterious effects of Na2S. Selectivity experiments using synthetic oxidized white liquor showed a significant decrease in the separation efficiency due to the presence of sodium hydroxide, sodium carbonate, and sodium sulfate in the synthetic extract.

A Fast and Sensitive Method Combining Reversed-Phase Chromatography with High Resolution Mass Spectrometry to Quantify 2-Fluoro-2-Deoxyglucose and Its Phosphorylated Metabolite for Determining Glucose Uptake

2019 ◽  
Author(s):  
Ashley Williams ◽  
Deborah Muoio ◽  
Guofang Zhang
Keyword(s):  
Glucose Uptake ◽  
Biological Samples ◽  
High Resolution Mass Spectrometry ◽  
Reversed Phase ◽  
Sodium Adduct ◽  
Negative Mode ◽  
Glucose Analogues ◽  
Positive Mode ◽  
Q Exactive ◽  
Glucose Analogue

Quantative measurements of the glucose analogue, 2-deoxyglucose (2DG), and its phosphorylated metabolite (2-deoxyglucose-6-phosphate (2DG-6-P)) are critical for the measurement of glucose uptake. While the field has long identified the need for sensitive and reliable assays that deploy non-radiolabled glucose analogues to assess glucose uptake, no analytical MS-based methods exist to detect trace amounts in complex biological samples. In the present work, we show that 2DG is poorly suited for MS-based methods due to interfering metabolites. We therefore developed and validated an alternative C18-based LC-Q-Exactive-Orbitrap-MS method using 2-fluoro-2-deoxyglucose (2FDG) to quantify both 2FDG and 2FDG-6-P by measuring the sodium adduct of 2FDG in the positive mode and deprotonation of 2FDG-6-P in the negative mode. The low detection limit of this method can reach 81.4 and 48.8 fmol for both 2FDG and 2FDG-6-P, respectively. The newly developed method was fully validated via calibration curves in the presence and absence of biological matrix. The present work is the first successful LC-MS method that can quantify trace amounts of a nonradiolabeled glucose analogue and its phosphorylated metabolite and is a promising analytical method to determine glucose uptake in biological samples.

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