Final answer:
The gas production in your ICP-OES standard could be due to reactions between strong oxidizers HNO3 and H2O2 with elements like phosphorus or due to the decomposition of peroxides. Ensure the purity of reagents and consider preparing solutions without hydrogen peroxide to prevent gas formation.
Step-by-step explanation:
It appears that there is a chemical reaction occurring in your ICP-OES standard solution that is generating gas, leading to pressure buildup in the storage bottle. Given that your standard contains HNO3 and H2O2, which are both strong oxidizers, there's a possibility that they are reacting with one or more of the elements in your solution, or with a contaminant. Phosphorus, in particular, can react with peroxides under certain conditions, forming phosphine gas (PH3) which is quite dangerous. It's also possible that there's a slow reaction of H2O2 decomposing to water and O2, especially if the solution is exposed to light or is not completely pure.
For troubleshooting this issue, you should ensure that all of your reagents are of high purity, especially the peroxide and nitric acid. You should also store the solution in a dark, cool place to minimize decomposition of H2O2. If the issue persists, consider preparing the solution without hydrogen peroxide to see if that prevents gas formation. The use of Ce4+ solutions, although not directly related to your current problem, are examples of redox reactions in analytical chemistry that involve different types of in situ reaction conditions, which can be sensitive to the presence of various reactants or contaminants.