Reagents used to prepare organic ICP standards, from scratch
Running an ICPOES or ICPMS on organic solvents is not easy, you may have problems such as coke / carbon deposits in the torch.

Also I would like to point out that sodium dicyclopentadienide is very sensitive to oxygen, it decomposes with great ease on contact with air. Ask almost anyone who has made ferrocene in the lab about this question.

I would like to suggest that you consider making an emulsion in water of the organic solution using a detergent such as triton-x100. I have heard of this method for running organic samples in a normal ICPMS but I have never tried using it.

In the ideal world what I would do would be to use a wet combustion (maybe use a acid digestion bomb such as a Parr 45 ml bomb) to convert the organic sample into a aqueous sample.

Another option would be to use neutron activation anaylisis, but these days it is very hard to find a strong neutron source suitable for this type of work. You would have to seal up samples in quartz tubes. I will warn you that even with a nuclear reactor and a good gamma spectrometer this type of work is far from trival.