scholarly journals Reduction of niobium pentachloride and tantalum pentachloride with niobium metal in a gas chromatograph

1967 ◽  
Author(s):  
David John Lorine
Keyword(s):  
Gas Chromatograph ◽  
Niobium Pentachloride

Optimization of the time the chromatograph thermostats exit to a given temperature

2020 ◽  
pp. 40-45
Author(s):  
Nadezhda O. Vzduleva ◽  
Valery B. Gitlin
Keyword(s):  
Heating Rate ◽  
Entire Range ◽  
Gas Chromatograph ◽  
Heating And Cooling ◽  
Operating Temperatures ◽  
The Stability

The problems of ensuring the stability of the temperature of the chromatographic experiment carried out using a serial gas chromatograph LGH-3000 are considered. Limiting the permissible heating rate of the chromatograph thermostats does not allow a quick transition to the new conditions of the chromatographic experiment in accordance with the requirements of the technical conditions. The processes of heating and cooling the thermostat are analyzed. It is shown that the ratio of the duration of the interval equal to the sum of the durations of the heating and cooling intervals to the duration of the heating interval is inversely proportional to the temperature of the chromatographic experiment. Based on this situation, an empirical algorithm is proposed for heating the thermostat to a given temperature, which made it possible to reduce the time it takes to reach a given temperature in the entire range of operating temperatures.

Methods to Determine Phytopharmaceuticals in Tobacco and Tobacco Products. 4th Report: A Procedure to Determine Vamidothion and its Metabolites/Methoden zur Bestimmung von Phytopharmaka in Tabak und Tabakerzeugnissen: IV. Mitteilung: Ein Bestimmungsverfahren fuer Vamidothion und seine Metaboliten

1977 ◽  
Vol 9 (2) ◽  
Author(s):  
A.N. Sagredos ◽  
R. Moser
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Acetic Acid ◽  
Magnetic Resonance ◽  
Aluminium Oxide ◽  
Nuclear Magnetic Resonance Data ◽  
Gas Chromatograph ◽  
Tobacco Products ◽  
Magnetic Resonance Data ◽  
Resonance Data

AbstractBased on previous work (7) a method to simultaneously determine vamidothion [I], vamidothion-sulfoxide [II] and vamidothion sulfone [III] in tobacco has been developed. The compounds are extracted with water/acetone/acetic acid from the tobacco, cleansed over an aluminium oxide column and then determined on the gas chromatograph with the specific sulphur detector. Rates of recovery are 70 % - 92 %, the determination level is 0.1 ppm. Mass spectrometry and nuclear magnetic resonance data of vamidothion [I], vamidothion-sulfoxide [ II ] and vamidothion-sulfone [III] are given.

New Methods for Analyzing Water Pollutants

1982 ◽  
Vol 14 (4-5) ◽  
pp. 59-71 ◽  
Author(s):  
L H Keith ◽  
R C Hall ◽  
R C Hanisch ◽  
R G Landolt ◽  
J E Henderson
Keyword(s):  
Amino Acids ◽  
Gas Chromatography ◽  
Two Dimensional ◽  
Gas Chromatograph ◽  
New Class ◽  
New Methods ◽  
System A ◽  
Drinking Waters ◽  
Computer Controlled ◽  
Nitrogen Containing Compounds

Two new methods have been developed to analyze for organic pollutants in water. The first, two-dimensional gas chromatography, using post detector peak recycling (PDPR), involves the use of a computer-controlled gas Chromatograph to selectively trap compounds of interest and rechromatograph them on a second column, recycling them through the same detector again. The second employs a new detector system, a thermally modulated electron capture detector (TMECD). Both methods were used to demonstrate their utility by applying them to the analysis of a new class of potentially ubiquitous anthropoaqueous pollutants in drinking waters- -haloacetonitriles. These newly identified compounds are produced from certain amino acids and other nitrogen-containing compounds reacting with chlorine during the disinfection stage of treatment.

Effects of Cooking Processes on Breath Hydrogen and Colonic Fermentation of Soybean

2020 ◽  
Vol 16 (4) ◽  
pp. 488-493
Author(s):  
Naoya Okumura ◽  
Naoya Jinno ◽  
Kentaro Taniguchi ◽  
Kenichi Tanabe ◽  
Sadako Nakamura ◽  
...  
Keyword(s):  
Healthy Adult ◽  
Area Under The Curve ◽  
Cooking Methods ◽  
Breath Hydrogen ◽  
Gas Chromatograph ◽  
Colonic Fermentation ◽  
Hydrogen Molecules ◽  
Nutritional Analysis ◽  
Hydrogen Level ◽  
Adult Volunteers

Background: Soybean is rich in dietary fibers; consequently, soybean ingestion considerably increases the breath level of hydrogen molecules via anaerobic colonic fermentation. However, the influence of cooking methods on this effect, which can affect the overall health benefits of soybean, remains unknown. Objectives: The aim is to examine whether different methods of cooking soybean affect the colonic fermentation process. Methods: Nine healthy adult volunteers participated in the study; they ingested either roasted soybean flour (kinako) or well-boiled soybean (BS). Differences in their breath components were compared. Both test meals were cooked using 80 g of soybeans per individual. After a 12 h fast, the participants ate the test meals, and their breath hydrogen level was analyzed every 1 h for 9 h by using a gas chromatograph with a semiconductor detector. In addition, particle size distribution and soluble/ insoluble fibers in the feces were examined. Results: The oro-cecal transit time did not significantly differ between individuals who ingested kinako and BS. However, the area under the curve between 7 and 9 h after the ingestion of BS was significantly increased compared with that after the ingestion of kinako. The nutritional analysis indicated that the content of both soluble and insoluble fibers in BS was higher than that in kinako. In addition, the levels of unfermented fragments and soluble/insoluble fibers in the feces were increased after the ingestion of kinako compared with those after the ingestion of kinako. Conclusion: Cooking methods alter the composition of non-digestible fibers in soybean, and this can result in the lack of fermentative particles in the feces, thereby causing alterations in the breath level of hydrogen via colonic fermentation.

Study on the precision of the activated charcoal solvent desorption procedure - Correlation of desorption efficiencies

1981 ◽  
Vol 46 (6) ◽  
pp. 1332-1347 ◽  
Author(s):  
Martin Koval
Keyword(s):  
Activated Charcoal ◽  
Carbon Disulphide ◽  
Internal Standard ◽  
Standard Addition ◽  
Published Data ◽  
Single Factor ◽  
Gas Chromatograph ◽  
Model Compounds ◽  
Single Factor Analysis ◽  
Acceptable Agreement

The described method uses activated charcoal sampling tubes for air sampling. Adsorbed compounds are eluted by the static desorption procedure with 1 ml of carbon disulphide, 0.5 ml of the supernatant is filtered off and, after internal standard addition, analysed on a gas chromatograph. Using synthetic calibration mixtures of model organic compounds with air, cumulative sampling and desorption efficiencies for 24 substances were determined for concentration ranges and sample volumes according to current Czechoslovak hygienic standards. Experimental results were treated with the single factor analysis of variance and the precision of the described procedure was estimated for the studied model compounds on the basis of residual sums of squares. Calculated values of cumulative sampling and desorption efficiencies and their precisions were compared with available published data and an acceptable agreement was found. In addition to that, cumulative sampling and desorption efficiencies were also found to be significantly correlated to molar volumes and other related molecular properties for some types of compounds.

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