scholarly journals Improved detection of honey adulteration by measuring differences between13C/12C stable carbon isotope ratios of protein and sugar compounds with a combination of elemental analyzer - isotope ratio mass spectrometry and liquid chromatography - isotope ratio mass spectrometry (δ13C-EA/LC-IRMS)

Apidologie ◽  
2008 ◽  
Vol 39 (5) ◽  
pp. 574-587 ◽  
Author(s):  
Lutz Elflein ◽  
Kurt-Peter Raezke
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Isotope Ratio Mass Spectrometry ◽  
Isotope Ratios ◽  
Stable Carbon ◽  
Stable Carbon Isotope Ratios ◽  
Carbon Isotope Ratios

scholarly journals A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

2015 ◽  
Vol 8 (6) ◽  
pp. 2301-2313 ◽  
Author(s):  
A. Kornilova ◽  
S. Moukhtar ◽  
M. Saccon ◽  
L. Huang ◽  
W. Zhang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Ratio ◽  
Isotope Ratios ◽  
Stable Carbon ◽  
Stable Carbon Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Concentration Measurements ◽  
Better Than

Abstract. A technique for compound-specific analysis of stable carbon isotope ratios and concentration of ambient volatile organic compounds (VOCs) is presented. It is based on selective VOC sampling onto adsorbent-filled cartridges by passing large volumes of air (up to 80 L) through the cartridge. The hydrocarbons are recovered by thermal desorption followed by two-step cryogenic trapping and then are separated by gas chromatography in the laboratory. Once separated, individual VOCs are subjected to online oxidation in a combustion interface and isotope ratio analysis by isotope ratio mass spectrometry. The method allows measurements of stable carbon isotope ratios of ambient aromatic VOCs present in low pptV to ppbV levels with an accuracy of typically better than 0.5 ‰. The precision of concentration measurements is better than 10%. Examples of measurements conducted as part of a joint Environment Canada–York University (EC-YU) measurement campaign at a semi-rural location demonstrate that the ability to make accurate measurements in air with low VOC mixing ratios is important to avoid bias from an overrepresentation of samples that are strongly impacted by recent emissions.

scholarly journals Stable carbon isotope ratios of toluene in the boundary layer and the lower free troposphere

2013 ◽  
Vol 13 (4) ◽  
pp. 11357-11394
Author(s):  
J. Wintel ◽  
E. Hösen ◽  
R. Koppmann ◽  
M. Krebsbach
Keyword(s):  
Boundary Layer ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Isotope Ratios ◽  
Free Troposphere ◽  
Stable Carbon ◽  
Stable Carbon Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Mixing Ratios

Abstract. Measurements of stable carbon isotope ratios in VOC are a powerful tool to identify sources or to track both dynamical and chemical processes. During the field campaign ZEPTER-2 in autumn 2008 whole air samples were collected on board a Zeppelin NT airship in the planetary boundary layer and the lower free troposphere over south-west Germany. These samples were analysed with respect to VOC mixing ratios and stable carbon isotope ratios using a gas chromatograph combustion isotope ratio mass spectrometer. In this study we present the results for toluene, one of the major anthropogenic pollutants. In the boundary layer we observed rather fresh emissions mixing into the background and derived a toluene source isotope ratio of δ13C = −28.2 ± 0.5 ‰. Using the concept of the effective kinetic isotope effect, we were able to separate the effects of dilution processes and photochemical degradation in the free troposphere. We estimated the photochemical age of toluene in the atmosphere in two different ways (using isotope ratios and mixing ratios, respectively). The results differ strongly in the planetary boundary layer, probably due to mixing processes, but are compatible with each other in the free troposphere.

scholarly journals A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

2015 ◽  
Vol 8 (1) ◽  
pp. 1365-1400
Author(s):  
A. Kornilova ◽  
S. Moukhtar ◽  
M. Saccon ◽  
L. Huang ◽  
W. Zhang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Ratio ◽  
Isotope Ratios ◽  
Stable Carbon ◽  
Stable Carbon Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Concentration Measurements ◽  
Better Than

Abstract. A technique for compound specific analysis of stable carbon isotope ratios and concentration of ambient volatile organic compounds (VOC) is presented. It is based on selective VOC sampling onto adsorbent filled cartridges by passing large volumes of air (up to 80 L) through the cartridge. The hydrocarbons are recovered by thermal desorption followed by two step cryogenic trapping and then are separated by gas chromatography in the laboratory. Once separated, individual VOC are subjected to online oxidation in a combustion interface and isotope ratio analysis by isotope ratio mass spectrometry. The method allows measurements of stable carbon isotope ratios of ambient aromatic VOC present in low pptV to ppbV levels with an accuracy of typically better than 0.5‰. The precision of concentration measurements is better than 10%. Examples of measurements conducted as part of a joint Environment Canada-York University (EC-YU) measurement campaign at a semi-rural location demonstrate that the ability to make accurate measurements in air with low VOC mixing ratios is important to avoid bias from an over-representation of samples that are strongly impacted by recent emissions.

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