ASTM Method E70 and Storage of CO2 Free Water - What do you use?
I am implementing ASTM E70 pH of Aqueous Solutions and have been trying to find a reasonable storage container for the CO2 purged Type II Reagent water needed to prepare the borax standard. I need it equipped with a CO2 filter. The only container I can find readily available is >$1500. Does anyone have an alternative that they use in their lab that they are willing to share? Thanks in advance!
Re: ASTM Method E70 and Storage of CO2 Free Water - What do you use?
Any glass container should work. I think the issue is the CO2 filter preventing any ingress of CO2 into the stored water. I'm not sure what the commercial versions of those may be, as different compounds have different capacities and equilibria for CO2 adsorption. However, I think the cost issue can be addressed in two ways. If you need large quantities for a large number of samples the cost should amortize fairly easily and inexpensively in the overall analysis. If you just want a large quantity available but are worried about the purity, I would recommend CO2 purging immediately before use of smaller quantities. You don't really need to have a large stockpile simply for convenience if purity is the issue.