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Posted: Mon Dec 22, 2008 12:51 am
by Noser222
Calculating amounts is more accurate?
Just from my perspective on the kinds of things we work on...ammonium acetate is so hygroscopic I'd rather rely on a pH check.
Posted: Mon Dec 22, 2008 3:58 pm
by HW Mueller
Even if one has trouble handling hygroscopic material (I havn´t noticed anything special, even the strong smell one gets upon opening ammoniumbicarb is not evident with my high grade NH4OAc) it would be advantageous to weigh. Weighing does not exclude using a pH meter. If one gets a huge discrepancy one should elucidate the reason for that. If you use only the pH meter how do you know that your NH4OAc was not 90% crud? Also, the rough titration methods one often uses with the "pure" pH meter method can yield different ionic strength buffer everytime one prepares it.
Just a few reasons (more are given elsewhere here) for me to convert to the weighing method a few years ago.
Posted: Mon Dec 22, 2008 5:31 pm
by Noser222
Yes, if a combination of weighing and pH check is what you are referring to, I agree with that.