I have a solution containing 500 mg/L of Cu and 29.2 g/L of EDTA. I'm attempting to digest the EDTA for ICP analysis.
Thank you.
Do I understand correctly, that you want to remove EDTA from solution to measure Cu? EDTA has a very low solubility in water under acidic condition. Add concentrated HClO4 to your solution to have about 1 M HClO4 and filter the precipitate.
https://www.researchgate.net/post/Does-anyone-have-an-idea-of-whether-EDTA-affect-the-measure-of-calcium-concentration-by-ICP-analysis
You don't have to destroy the EDTA. It is best to dilute it as much as possible, e.g. 100 times. And add EDTA to the calibration solutions.
If the copper concentration was not 500 mg/L, but 500 microg/L, it would be a different matter.
ZJ
I concur Dr. Jonca's suggestion to dilute the samples. The dilution factor may depend on your ICP system (ES, MS, etc.). If you dilute it by 100X, your Cu concentration will be in the vicinity of 5 ppm, which can very well be measured by any ICP system. Then your EDTA concentration will be 0.29 g/L (0.029%) which can be easily handled by the ICP. However, there can be slight matrix suppression/enhancement due to the organic content in the sample. So, if you are interested in very high accuracy, you may prepare your calibration standards also in EDTA matrix at the same concentration used for measurement (0.029%).
In fact, trying to measure Cu directly at 500 ppm is not a good idea even if you don't have EDTA in the solution. Generally keeping the targetted concentration in the range 1-10 ppm would be optimal.
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