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UVvis · 03/11/2011, 07:29 AM

To try to add some emphasis on a couple of points brought up.

High purity water is simply water. It is not magical or dangerous. It has no magical ability to pull anything from your body if consumed (where are these ions going to go anyway?). You would have to be on a very odd low ionic diet, and then drink large amounts of high purity water to have a negative effect on the human body.

I had several catridges I needed to use up on an old millipore water machine that one of my old institutions planned to get rid of. I consumed around 8-10 liters of 18.2Mohm water per day for about a month. This was in a very arid environment where my daily liquid consumption was around 12-14 liters per day. I survived, and had a normal blood and urine electrolyte balances per my monthly physical (little low on urine specific gravity, but that was preferred medically for that environment). My diet provided all the nutrients and ion loading I needed. Honestly, your average 1st world human consumes more ions than needed.

High purity water is not particularly acidic, or basic. It is also virtually impossible to get a meaningful pH measurement on very pure water sources as these is such a low ionic balance, that the results are meaningless. Default value of OH and H ions is equal, hence the pH is 7. Atmospheric gasses will drive measure pH down quickly, especially with a 380-390ppm balance of CO2 based on global averages. This does not mean acidic, as much as non-buffered.

As far as leeching goes, pure water has such a low concentration gradient in it, that it is easier to dissolve ionic substances in over less pure waters. This is more a factor of the contribution of other ions than the 'aggresive nature' of water. It is simply easier for the majority of people to understand if you call it aggresive versus saying that it is readily accepting of any ion dissolution from the water's containment.

So back to the original topic. That PO4 coming off the can isn't doing so as strictly a result of the high purity water. As your salt water test proved, it is there in the plastic as a contaminate, even the salt water had some orthophosphate dissolve into it.

HDPE sample bottles need to be well cleaned prior to use for lab grade studies.

And to add some randomness, things like hexavalent chromium, arsenate, and nitrites will give positives on ascorbic acid reduced phosphate methods.

03/11/2011, 07:29 AM	#12
UVvis Registered Member Join Date: Aug 2010 Posts: 154	To try to add some emphasis on a couple of points brought up. High purity water is simply water. It is not magical or dangerous. It has no magical ability to pull anything from your body if consumed (where are these ions going to go anyway?). You would have to be on a very odd low ionic diet, and then drink large amounts of high purity water to have a negative effect on the human body. I had several catridges I needed to use up on an old millipore water machine that one of my old institutions planned to get rid of. I consumed around 8-10 liters of 18.2Mohm water per day for about a month. This was in a very arid environment where my daily liquid consumption was around 12-14 liters per day. I survived, and had a normal blood and urine electrolyte balances per my monthly physical (little low on urine specific gravity, but that was preferred medically for that environment). My diet provided all the nutrients and ion loading I needed. Honestly, your average 1st world human consumes more ions than needed. High purity water is not particularly acidic, or basic. It is also virtually impossible to get a meaningful pH measurement on very pure water sources as these is such a low ionic balance, that the results are meaningless. Default value of OH and H ions is equal, hence the pH is 7. Atmospheric gasses will drive measure pH down quickly, especially with a 380-390ppm balance of CO2 based on global averages. This does not mean acidic, as much as non-buffered. As far as leeching goes, pure water has such a low concentration gradient in it, that it is easier to dissolve ionic substances in over less pure waters. This is more a factor of the contribution of other ions than the 'aggresive nature' of water. It is simply easier for the majority of people to understand if you call it aggresive versus saying that it is readily accepting of any ion dissolution from the water's containment. So back to the original topic. That PO4 coming off the can isn't doing so as strictly a result of the high purity water. As your salt water test proved, it is there in the plastic as a contaminate, even the salt water had some orthophosphate dissolve into it. HDPE sample bottles need to be well cleaned prior to use for lab grade studies. And to add some randomness, things like hexavalent chromium, arsenate, and nitrites will give positives on ascorbic acid reduced phosphate methods.