I have a problem with my tree core samples. After graining them with a Wig-L-Bug, we noticed that some of the plastic material which the capsules of the Wig-L-Bug are made with was mixed with our samples turning a little dark the samples. We didn’t pay to much attention to that hoping that it will disappear with the first part of the cellulose extraction (extraction of waxes, oils and resins and Boiling-water soluble extraction).

Question

After the first part of the extraction, the plastic is still mix with the samples. Do you think the plastic will affect the 13 carbon isotope information? What can I do to repair the damage?

thanks

Domingo.sancho

As long as you are doing a radioactve activity measurement, discoloration and chemical reactions will not have an effect unless they cause some of the C-14 to be released as CO2.

That's a problem we all learn the first time we use a Wig-L-Bug. There is enough plastic in samples "wiggled" for 30 seconds to a minute to obtain a plastic IR spectrum. How will you be determinig the C-13. That may be the answer. One thing you can do is to make a blank by shaking something without C-13, then checking to see if you can detect C-13 in the plastic. By the way, is that C-13 or C-14?

We were going to send the samples to a lab where they have a mass spectrometer and they will calculate the carbon stable isotopic composition through dedicated combustion and pyrolysis elemental analyzers.