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Posted: Thu Sep 02, 2010 3:18 pm
by HW Mueller
Right, you should not assume that a chemist will think v/v when that is not so stated, and also you shouldn´t assume that anybody will know what % H3PO4 you used.

You are not serious about asking that last question, are you?

Posted: Thu Sep 02, 2010 3:54 pm
by carls
Right, you should not assume that a chemist will think v/v when that is not so stated, and also you shouldn´t assume that anybody will know what % H3PO4 you used.
I stated concentrated H3PO4. Besides, any chemist could easily deduce where 15mM came from since it is common knowledge that conc H3PO4 is 15M.

To avoid future long,pointless discussions I'll be sure to state all units.
You are not serious about asking that last question, are you?
Yes. Hopefully I'll learn something. That's the point of this forum, right?

Posted: Fri Sep 03, 2010 9:44 am
by HW Mueller
I don´t go by common knowledge when I prepare buffers.

If you still have to learn that the PO4 with three H substituents will behave different chemically and chromatographically than a PO4 with one H substituent, and one long carbon chain substituent, + that large other residue, then I recommend you hit the books. I have no inclination to give a course in basic organic or analytical chemistry here.

Posted: Fri Sep 03, 2010 12:43 pm
by carls
If you still have to learn that the PO4 with three H substituents will behave different chemically and chromatographically than a PO4 with one H substituent, and one long carbon chain substituent, + that large other residue, then I recommend you hit the books. I have no inclination to give a course in basic organic or analytical chemistry here.
Apparently we are having communication problems...

My question to you was: please explain what "grave" differences (such as the difference between Cl2 and Cl- you mention earlier) exist in the chemical and/or physical properties of phosphate when incorporated in an analyte that invalidate generalizing the knowledge of free phosphate chemistry to it.

Again, this is limited to the differences in chemical and/or physical properties that would affect chromatographic performance.

Here is the statement you made earlier that initiated this last discussion
"For the few physical and chemical similarities there are many grave differences in the P species"