Do mason jars affect the purity of water?

[bubblypop98]

In my project I am making a solar-powered water desalinator. I need a conductivity meter to measure the purity of the water, but it is not available to me yet. In the meantime, since this is the first sunny weekend so far, I wanted to conduct trials. Could I contain the purified water in a mason jar until it arrives to keep it from evaporating? Would this affect the water at all? Please help!

[rmarz]

bubblypop98 - You should be able to store reasonably pure water in a clean, glass Mason jar for a long period of time. Try not to let the liquid interact with the lid, and don't leave too large of an air volume (gasses such as CO2 will dissolve into the water and cause a loss of purity). Although the lids are usually well coated metal, if there were breaches in the coating some metallic ions may leach into the water. Very pure water, such as distilled water or deionized water will exhibit very high resistivity, upwards of several megohms to over 20 megohms. I haven't researched this experiment, but saline water would have a very low resistivity, many magnitudes of difference to your pure standard.

Rick Marz