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).
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.
If you are sending the samples to a lab that will use a mass spectrometer to analyze the carbon stable isotopic composition, they should be able to identify and account for any plastic contamination in the samples. When you send the samples, it is recommended that you inform the lab about the plastic contamination issue so that they can take appropriate measures during analysis.
In terms of repairing the damage, it may not be possible to completely remove the plastic from the samples. However, the lab should be able to conduct the analysis in a way that minimizes the impact of the plastic on the results. They might also apply correction factors based on the known plastic contamination to ensure accurate interpretation of the carbon isotopic composition.
Overall, it is important to communicate the issue to the lab and collaborate with them to determine the best approach for analyzing the samples considering the plastic contamination.