Can anyone explain the differences between Milli-Q and DD water in terms of purity, conductivity, ions, Chemical differences etc. And what makes these differences ?
Distilled water is made by continuous (as opposed to fractional) distillation of a water source. Many times it is distilled a second and even a third time. The problem with it is that since it is continuous distillation, some contaminants will come across with the water.
Milli-Q water is made by passing the source water through mixed bed ion exchange and organics (activated charcoal) cartridges. The source does not have to be distilled or deionized (reverse osmosis) but it will help extending the cartridge life. Finally the water is passed through a filter (0.22 um) which should pull out any intact organisms. Sometimes there is a UV lamp attached, as well.
The purity of the water is monitored by measuring the conductivity. The higher resistance, the fewer ions in the water. A value greater than 18.2 MΩ cm-1 (@ 25 °C) is desirable for Milli-Q. Double Distilled Water has a value between 15 and 18 MΩ cm-1 (@ 25 °C).
Distilled water is made by continuous (as opposed to fractional) distillation of a water source. Many times it is distilled a second and even a third time. The problem with it is that since it is continuous distillation, some contaminants will come across with the water.
Milli-Q water is made by passing the source water through mixed bed ion exchange and organics (activated charcoal) cartridges. The source does not have to be distilled or deionized (reverse osmosis) but it will help extending the cartridge life. Finally the water is passed through a filter (0.22 um) which should pull out any intact organisms. Sometimes there is a UV lamp attached, as well.
The purity of the water is monitored by measuring the conductivity. The higher resistance, the fewer ions in the water. A value greater than 18.2 MΩ cm-1 (@ 25 °C) is desirable for Milli-Q. Double Distilled Water has a value between 15 and 18 MΩ cm-1 (@ 25 °C).
Thank you Sir.
Can you please elaborate on the " Since it is continuous distillation, some contaminants will come across with the water". What are the chances to get the contamination when we are collecting the condensed water directly into a clean container?
For double distilled water you should consider that as soon as you use either contaminated or inappropriate vessels, you will get contaminations. So as soon as you use a plastic container, you will have some kinds of plasticisers in your water. We then use only glas ware that was rinsed at least 3 times with tripple distilled water.
Milli-Q water is produced by reversed osmosis that normally can even remove bigger ions.
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