CO2 free water for electrochemical detector

[thohry]

Hi all,

We are analyzing gentamicin by HPLC-ECD according to European Pharmacopoeia. And in the method they say use dioxide carbon free water for preparing mobile phase.
How could I prepare such the water. Is it OK if I use just DI water or bottled water from Merk.
Thanks for any suggestion.

[scottythree]

The EP probably has directions to prepare CO2 free water. This is from the USP:

Water, Carbon Dioxide-Free—It is Purified Water that has been boiled vigorously for 5 min or more and allowed to cool while protected from absorption of carbon dioxide (CO2) from the atmosphere, or Purified Water that has a resistivity of NLT 18 Mohm-cm.

[thohry]

The EP probably has directions to prepare CO2 free water. This is from the USP:

Water, Carbon Dioxide-Free—It is Purified Water that has been boiled vigorously for 5 min or more and allowed to cool while protected from absorption of carbon dioxide (CO2) from the atmosphere, or Purified Water that has a resistivity of NLT 18 Mohm-cm.

Thank you very much !

[DR]

That said, I suspect that He sparging would get you there too. Once left exposed to air, your water will start to re-equilibrate to about 3ppm CO2.

[Markus Laeubli, Metrohm]

Is it OK if I use just DI water or bottled water from Merk.

Electrochemical detection is sensitive to a lot of organic compounds. I therefore would not use DI water as it still can contain organics.
I recommend to use ultrpure water out of a purification system applying UV digestion (Millipore, Barnsted ELGA etc.).