Sulfuric Acid

[SuperChemie]

Does anyone know of a way to measure Sulfuric Acid/Sulfate Ion by HPLC? Currently I am trying to measure 0-100ppm Sulfate using an Indirect UV method I found on the Hamilton website. It uses a PRPX100 column and uses Hydroxybenzoic Acid in H2O/MeOH, pH 8.9 for a mobile phase. I believe I can see the sulfate ion peak but it is very broad and low levels are hardly distinguishable.

Has anybody used this before or something that works perhaps better than this?

[Consumer Products Guy]

We use a PRPX100 column (100mm x 4.6mm i.d.) but with 4.8 mM KHP HPLC mobile phase (0.97 - 0.99 g KHP into a 1000 ml volumetric flask; mix and dilute to volume with HPLC water, filter through a 0.45u membrane filter). Our peaks are nice shape at about 4 minutes at 1.00 ml/min.

We use conductivity detector for this (I've never tried with UV detector and vacancy chromatography).

[Vlad Orlovsky]

here are few methods for analysis of sulfate (the last one us used by two pharma companies). ELS detection with ammonium formate or acetate
http://www.sielc.com/compound_315.html

Contact me if you have question.

[SuperChemie]

[quote="Consumer Products Guy"]We use a PRPX100 column (100mm x 4.6mm i.d.) but with 4.8 mM KHP HPLC mobile phase (0.97 - 0.99 g KHP into a 1000 ml volumetric flask; mix and dilute to volume with HPLC water, filter through a 0.45u membrane filter). Our peaks are nice shape at about 4 minutes at 1.00 ml/min.

We use conductivity detector for this (I've never tried with UV detector and vacancy chromatography).[/quote]

This method sounds similar to the one I am using but with conductivity. Do you have anything else in your samples? Do you do any extractions before shoot on your samples? I ask because I am trying to measure Sulfuric Acid in process samples so there is a lot of other compounds in the sample. So I have to extract an aqueous layer (which should hopefully contain nearly all of the acid) before I run the sample.

[alperbayrakdar]

How did you set the pH at 8.9

[vockhead]

Just mentioned this in another post. I use the same column, 5 mM NaOH, 4 mM p-hydroxybenzoic acid, 0.1 mM NaSCN and 2.5% MeOH as our mobile phase. Haven't had any problems.