Milli-Q

Milli-Q water is deionized water that has been purified only in a Milli-Q system available from Millipore Corporation. Milli-Q for water and for water purifying systems are registered trademarks of Millipore Corporation. The purity of the water is monitored by measuring the conductivity. It is important for many chemical applications to measure without parasitic impurities. Therefore the ions in water should be minimized. The quality of deionized water can be detected through the resistance in well-defined conditions. The higher resistance is brought by missing ions, which normally serve as charge carriers. A value of resistivity greater than 18.2 MΩ cm at 25 °C is desirable. As a final step, the water is normally dispensed through a 0.22 μm membrane filter.