scholarly journals A new ice mill allows precise concentration determination of methane and most probably also other trace gases in the bubble air of very small ice samples

1993 ◽  
Vol 39 (131) ◽  
pp. 199-203 ◽  
Author(s):  
Andreas Fuchs ◽  
Jakob Schwander ◽  
Bernhard Stauffer
Keyword(s):  
Trace Gases ◽  
Extraction System ◽  
Air Bubbles ◽  
Gas Chromatograph ◽  
Milling Cutter ◽  
Concentration Determination ◽  
The Future

AbstractA new extraction system has been constructed and tested which allows the extraction of gases from air bubbles in ice without melting it. An ice sample of up to 20 g is crushed in a sealed container by a milling cutter and the gas escaping from the opened bubbles is flushed with helium to a Porapak column where it is stored until its injection into the gas Chromatograph. To avoid any contamination with CH4produced by friction in the gear section, a helium-flushed rotary feed-through is used. CH4analyses on ice samples of about 10 g from the last 1000 years give precise and reproducible results. In the future, it is planned to measure also the CO2and N2O concentrations on the same sample.

scholarly journals A new ice mill allows precise concentration determination of methane and most probably also other trace gases in the bubble air of very small ice samples

1993 ◽  
Vol 39 (131) ◽  
pp. 199-203 ◽  
Author(s):  
Andreas Fuchs ◽  
Jakob Schwander ◽  
Bernhard Stauffer
Keyword(s):  
Trace Gases ◽  
Extraction System ◽  
Air Bubbles ◽  
Gas Chromatograph ◽  
Milling Cutter ◽  
Concentration Determination ◽  
The Future

AbstractA new extraction system has been constructed and tested which allows the extraction of gases from air bubbles in ice without melting it. An ice sample of up to 20 g is crushed in a sealed container by a milling cutter and the gas escaping from the opened bubbles is flushed with helium to a Porapak column where it is stored until its injection into the gas Chromatograph. To avoid any contamination with CH4 produced by friction in the gear section, a helium-flushed rotary feed-through is used. CH4 analyses on ice samples of about 10 g from the last 1000 years give precise and reproducible results. In the future, it is planned to measure also the CO2 and N2O concentrations on the same sample.

scholarly journals A New Dry Extraction System for Gases in Ice

1984 ◽  
Vol 30 (106) ◽  
pp. 358-361 ◽  
Author(s):  
Ernst Moor ◽  
Bernhard Stauffer
Keyword(s):  
Extraction System ◽  
Air Bubbles ◽  
Milling Cutter

AbstractA new extraction system has been designed and constructed which allows the extraction of gases from air bubbles in ice without melting it. The ice sample of about 500 g is crushed an evacuated container by a milling cutter, and the gas escaping from the opened bubbles is collected by condensation at 15K. Results of CO2 analyses of extracted gases are discussed with respect to possible contamination risks by the system.

scholarly journals A New Dry Extraction System for Gases in Ice

1984 ◽  
Vol 30 (106) ◽  
pp. 358-361 ◽  
Author(s):  
Ernst Moor ◽  
Bernhard Stauffer
Keyword(s):  
Extraction System ◽  
Air Bubbles ◽  
Milling Cutter

AbstractA new extraction system has been designed and constructed which allows the extraction of gases from air bubbles in ice without melting it. The ice sample of about 500 g is crushed an evacuated container by a milling cutter, and the gas escaping from the opened bubbles is collected by condensation at 15K. Results of CO2analyses of extracted gases are discussed with respect to possible contamination risks by the system.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Concentration determination of chromatin in unstained resin-embedded sections by means of Z-contrast in STEM

1990 ◽  
Vol 48 (2) ◽  
pp. 186-187
Author(s):  
M. Haider ◽  
B. Bohrmann
Keyword(s):  
Energy Loss ◽  
Freeze Substitution ◽  
Biological Macromolecules ◽  
Local Concentration ◽  
E Coli ◽  
Concentration Determination ◽  
Phosphorous Content ◽  
Z Contrast ◽  
Electron Energy Loss

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.

Improved Cleanup and Derivatization for Gas Chromatographic Determination of Monosodium Glutamate in Foods

1983 ◽  
Vol 66 (6) ◽  
pp. 1528-1531 ◽  
Author(s):  
Hiroshi Nakanishi
Keyword(s):  
Glutamic Acid ◽  
Acid Derivative ◽  
Monosodium Glutamate ◽  
Chromatographic Determination ◽  
Flame Ionization Detection ◽  
Gas Chromatograph ◽  
Flame Ionization ◽  
Acetone Water ◽  
Chromatographic Procedure

Abstract A gas chromatographic procedure is described for determining monosodium glutamate (MSG) in several types of food. A sample is extracted with acetone- water (1 + 1). Acetone is evaporated and an aliquot of the extract is buffered with 1M NH4OH-1M NH4CI pH 9 solution, and chromatographed directly on a column of QAE Sephadex A-25 that has been pretreated with the same buffer. MSG is eluted with 0.1N HC1, and a portion of the eluate is evaporated to dryness and reacted with dimethylformamide( DMF)-dimethylacetal to form the glutamic acid derivative, which is injected into a gas chromatograph and measured by flame ionization detection. Recoveries of MSG from sample fortified at 5-500 mg ranged from 92.8 to 100%.

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