Are concentrated salt solutions stable over time?

I have to use dilute salt solutions incredibly frequently, and it takes valuable time to make them from pure reagents every time I need them.


Are concentrated salt solutions fairly stable over time?
Does anyone know of any papers describing their ability to maintain static concentrations for long periods?


Edit:


To qualify, I am curious about a wide range of salts. NaCl, ammonium chloride, magnesium sulfate, calcium chloride, potassium phosphate etc...


I am also not especially concerned about analytical precision for my use, but understanding how this could be affected might be useful to others.




Salt solutions generally do not spontaneously change in concentration. However, there are a few factors that could influence this: the first one is that the solvent (water, for example) could evaporate, increasing the concentration of the salt. You can prevent this by sealing your containers. The second one is that, as the temperature decreases, salts could crystallise out of the solution. However, this can be easily fixed by re-warming the solution.


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