Chemical Stability and Compatibility - Mulit-element instability at 10 ppm

There are several possibilities, but the likely culprits are rare earth fluorides. It’s not clear what the exact nature of the starting 1000 ppm standards were, but we are assuming the Nb, Sb, and Zr originally were in HNO3/HF matrices, and when these standards were combined with the rare earths Er, Nd, and Sc the precipitate(s) formed. These precipitates would most likely be white. If the precipitate is black, then reduction of Pd could be occurring. Other concerns with this particular mixture include the stability of iodide in an acidic matrix (what was the iodide staring material and original matrix), and the chemical form of the S used (sulfate or an organic such as methanesulfonic acid). A great deal of information regarding element and matrix compatibility can be found on our Interactive Periodic Table (https://www.inorganicventures.com/periodic-table). If you could provide any additional information regarding the 1000 ppm single element solutions you started with, we may be able to offer more detailed suggestions.