msa analysis

[gcguy]

I am trying to find a technique for analysis low levels of msa in dmf. Have tried ilc but msa elutes with formic and acetic acid on the system I have. The sample contains both these. Anybody got any ideas?

[Chris Pohl]

gcguy,

These analytes are easily separated via ion exchange. With a suppressor, the eluent ions can be removed and the eluent can then be directly coupled to MS. The IonPac AS11-HC from Dionex is a good choice for this separation.

[gcguy]

What sort of column/eluent would do this seperation? I am currently using a metrohm supp 5 with a carbonate/bicarb eluent without achieving a seperation.
gcguy

[Chris Pohl]

gcguy

As I mentioned, the best option is the IonPac AS11-HC. This column uses a hydroxide eluent. If you are only interested in these three analytes (MSA, formic, acetic) then this can be handled under isocratic conditions with an eluent concentration around 5 mM. Generally, however, this column is used under gradient conditions in order to apply it to a wider range of analytes.