Sulfuric acid in mobile phase

[Chandresh K. Soni]

does any body tried sulfuric acid in water as the mobile phase with organic solvents. if yes then pls guide how and when this is used and what precaution is require.

[tom jupille]

The only time I've ever done it was in ion-exclusion separations of organic acids on PS-DVB based cation exchangers, like this:



No special precautions beyond the usual laboratory precautions dealing with sulfuric acid. Note that these are *very* dilute, and I would worry about cleaving off bonded phase if used with a silica-based column.

[scottythree]

Waters does not recommend sufuric acid concentrations of >0.2M for their 2695 Alliance systems. Agilent does not recommend to use high concentrations of it in their 1100/1200 systems. Sulfuric acid will corrode your HPLC's stainless steel. Agilent further recommends to use phosphoric acid or phosphate buffers instead if your methodology permits.

[Chandresh K. Soni]

thanks tom,
I think there is too much precautions required related to HPLC. we must focus on Tubing which is normally made from SS b'use upon long time if system runs on the same mobile phase I have the doubt on these tubing's may corrode the same is for detector tubing's also apply.

should I require to do more focus on that part or not.

though I will try on very low concentration like 0.025mole% or it requires more low level.

[M Farooq]

Why do you need sulfuric acid in the mobile phase? As you said, it will corrode most metallic parts in ordinary HPLCs. The tubing is not as important for corrosion problems, most of the corrosion will occur in the metallic frits. Introduction of metallic impurities on the column surface will lead to retention time changes.
Methanesulfonic acid is regularly used in ion chromatography, but everything is made of plastics there, including the frits.

[Vlad Orlovsky]

We often use sulfuric acid in the mobile phase as source of ions and low pH. In mixed-mode chromatography it is viable choice. It produces very good peak shape, it is fully transparent at very low wavelength and it can supress ionization of the stationary phase or analyte if you need this. Sometimes for charged analytes you observe a focusing" effect, when you peak comes out as an extremely sharp one, almosy like in GC (see example below)
http://www.sielc.com/Compound-Aminosugar.html
http://www.sielc.com/Compound-Cytidine- ... phate.html
http://www.sielc.com/Compound-EDTA-Ethy ... -Acid.html

and much more here: http://www.sielc.com/Applications_By_Compound.html