Removing CO sub(2) from Atmospheric Samples for Radiocarbon Measurements of Volatile Organic Compounds

In principle, biogenic VOCs can be quantitatively distinguished by the isotopic carbon-14 content of a VOC sample. However, one problem that must be solved in applying the super(14)C approach is separating the VOC component in a sample of ambient air from the far larger amount of carbon dioxide that...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 1996-04, Vol.30 (4), p.1092-1092
Main Authors: Rasmussen, Reinhold A, Lewis, Charles W, Stevens, Robert K, Ellenson, William D, Dattner, Stuart L
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In principle, biogenic VOCs can be quantitatively distinguished by the isotopic carbon-14 content of a VOC sample. However, one problem that must be solved in applying the super(14)C approach is separating the VOC component in a sample of ambient air from the far larger amount of carbon dioxide that also contains super(14)C. Lithium hydroxide is known to be an aggressive scavenger of CO sub(2), and two methods for exposing atmospheric samples to LiOH were investigated, in which the sample air flowed through either a LiOH-coated annular denuder or through LiOH granules in a packed tube. For both methods, CO sub(2) removal factors were measured. Results found that both methods were effective in drastically decreasing CO sub(2) in atmospheric samples. In both methods, CO sub(2) was routinely decreased from nominal ambient concentrations of 360 ppm to 20 30 ppb. Little effect was seen on the VOC content in the atmospheric samples, but aldehydes exhibited the greatest loss during CO sub(2) removal.
ISSN:0013-936X