Atmospheric helium isotope ratio.

Changes in the atmospheric helium isotope ratio over the past 40 years

Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane

We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS) technique for high-precision δD and δ13C measurements of atmospheric methane on 40 mL air samples. CH4 is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve switching. Chemical agents are avoided. Trace amounts of interfering compounds can be separated ...

Simulation of a Helium Atmospheric Plasma Jet Using Fluid Equations

In this study, a cold atmospheric He plasma jet is investigated. The jet is of dielectric barrier discharge type, consisting of a dielectric tube with two metal ring electrodes. The continuity, momentum and energy conservation equations as well as the Poisson equation for obtaining the potential and the electric field, accompanied with the ideal gas laws, are used for the simulation. The result...

Isotope Ratio Mass Spectrometry.

Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and...

Delta13C stable isotope analysis of atmospheric oxygenated volatile organic compounds by gas chromatography-isotope ratio mass spectrometry.

We present a new method for analyzing the delta(13)C isotopic composition of several oxygenated volatile organic compounds (OVOCs) from direct sources and ambient atmospheric samples. Guided by the requirements for analysis of trace components in air, a gas chromatograph isotope ratio mass spectrometer (GC-IRMS) system was developed with the goal of increasing sensitivity, reducing dead-volume ...