IC method for MSA and BSA?

[duantech]

Has anyone tried using IC for analysis of MSA and BSA? MSA sure is a normally used for making IC eluent. What difficulties could we have if using IC to analyze them ?

[Mark Tracy]

MSA (methanesulfonic acid) is used to make eluent for cation analysis. You would be analyzing for the anion with either KOH or Na2CO3/NaHCO3 in the eluent. On an AS15 column with a KOH gradient, MSA elutes between formate and chloride. See the chromatogram on page 10 of: http://www1.dionex.com/en-us/webdocs/38 ... 040406.pdf

[Chris Pohl]

duantech,

MSA invariably elute before chloride on virtually all anion exchange phases. Analyzing both MSA and BSA (assuming that BSA means butanesulfonic acid) can be done on most anion exhange columns although in some cases BSA may not be resolved from chloride or may not necessarily exhibit very good chromatographic performance. Columns which allow isocratic separation of MSA and BSA with both ions eluting between fluoride and chloride include the IonPac AS9-HC, the IonPac AS4A-SC, the IonPac AS12A and the IonPac AS19. The latter column uses hydroxide eluent while the former columns use carbonate based eluents.

[duantech]

thanks a lot for the information.

duantech

[ljc]

Try using the DIONEX NS1 15 cmx4mm 5u column and TBAOH 5 mM eluent at 1 mL/min, using the new SRS300 anion suppressor (kudos to DIONEX for this improvement in backpressure tolerance) in chemical suppression mode with 25 mM H2SO4 as regenerant at around 3 mL/min (no autoregen, unplug the cord !). Add acetonitrile to the eluent starting aound 10% and work your way up until you get the separation / retention you want. I've had good luck with this combination for other anions, it might work for MSA and BSA. I premix the TBAOH with ACN once I find the right percentage and pump isocratically to minimize baseline noise. You can do this on any HPLC but using the Dionex ED40 with their columns has been very successful (P.S. Dionex that's a GREAT little versatile electrochemical detector hope you support it until I retire).

[JMadden]

Duantech and Mark,

I would recommend against using the AS15 to analyze for BSA, it is very strongly retained and even under gradient conditions is a long analysis.

You can add the AS22 and AS23 to Chris’ list of recommended columns, I would choose the AS23 as it has very good resolution of both from chloride and doesn’t add much time compared to the AS22.