Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: matso on September 05, 2011, 12:31:39 AM
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Hi,
New to these boards. I am working on an interesting problem and was looking for some suggestions. I am looking to determine the concentration of the degradation acids (primarily glycolic and formic) in a sample of used heat transfer solution (60:40 blend of monoethylene glycol). Ideally, I would like to be able to differentiate between the different organic degradation acids, however I am looking to avoid IC due to certain budgetary constraints. I was wondering if any of you could suggest a clever method for determining the concentration of these degradation acids separately. There are likely going to be a lot of contaminants in the solution including iron and copper ions and corrosion byproducts, chloride ions, and various hydrocarbons. I realize I can determine the total acidity by performing an acid/base titration with an indicator. A contact of mine recently suggested that the oil and gas industry used (perhaps still uses) potentiometric titration to determine the concentration of specific acids. I have done a little research, and unless there is a specific method I am missing, I can only see being able to calculate the total acidity. Is there some advantage of using potentiometric titration that I am missing? Or am I going to get the same information as I would from an acid/base titration w/ an indicator? Thanks for your help.
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pKa difference is way too small (3.75 vs 3.83) to separate them by titration, probably even in non-aqueous solvent. As far as I know potentiometric titration won't change it.
No ideas at the moment.