1. Remember to include your name and affiliation (ELECTROFIBER TECHNOLOGIES) in a signature block. That is why no one is responding.
2. I assume that you have these metals in an acid solution, but you did not mention what kind.
3. All of these metals are redox-active; and acid solutions catalyze the redox reactions. I imagine that has something to do with your missing metals.
4. Possible solutions: A. dilute the solutions further to slow any redox reactions that might result in less soluble forms. B. Add a chelating ligand like Cl- from HCl or high metals purity L-cysteine to shift the metal equilibria away from the free redox-active form to complexes, which should keep them from causing mischief.
R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Maria La Torre
Sent: Friday, March 31, 2017 3:31 PM
To: [log in to unmask]
Subject: Cu Ni Fe Analysis Using MP-AES
I am analyzing a series of solutions that contain Ni, Fe, and/or Cu using an Agilent MP-AES.
The solutions were prepared from stripping plated metals from carbon fiber. I have determined the expected weight % metals gravimetrically from the fiber before and after stripping. The analysis solutions are matrix matched to the respective standards.
I obtain expected results when analyzing solutions containing Ni and Iron (i.e. the results from the AES correlate well with the % metals recovery and the measured Ni and Fe concentration are within the expected range of the plating solutions).
The results are significantly lower than expected when analyzing solutions containing Ni, Fe, and Cu. The measured concentration of all elements from the AES are significantly lower than the gravimetric % metals recovery.
I would be interested in ideas on how to reconcile the differences between the gravimetric analysis and the AES results.