Ultra pure water is water nearly or completely devoid of contaminants.
These laboratory water purification systems can achieve up to 18 dot 2 MOhm cm in resistivity and can reduce organic carbon to less than 50 ppb.
Ultrapure water systems are an important component for laboratories across markets including manufacturing and the semi conductor industry. Whenever resulting in extremely low total organic carbon, An ultrapure water system is equipped with ultra filters to remove endotoxins, DNase and Rnase left over from bacteria destroyed by UV. Now regarding the aforementioned fact… An ultra pure water system eliminates bacteria with UV radiation. These ultra pure water systems remove chemical contaminants through de ionization and reverse osmosis. They can be expensive and are not always necessary, calibration baths are an easy way to ensure this.
You need your methods to be accurate and repeatable, whenever it boils down to calibration. In some cases, a bath circulator or water bath can work just as well.