Chromatography Forum

I set up a GC test to check for a contaminant in a suspected lot of this material (maleic anhydride). Since it's a solid at room temperature, I dissolved 0.1g of maleic in 3 ml of acetone. The testing for the contaminant worked just fine this way and proved what was suspected. What is interesting is that if I take and do a norm% on the chromatograms, it looks like I may have a suitable maleic anhydride purity test in that these results also correlate well on several samples with the production problems.

I'm not convinced that the MA makes it through the inlet unscathed and certainly don't want to report erroneous results.

5 uL injection
split=10
inlet = 200C
TCD = 250C
30M x 530 x 1um wax
oven 50/5/5/200/1

Anyone with experience doing anhydrides directly without derivation?

I have done similar analyses.

The impurities don't make it through the column in many cases, but the anhydrie should be stable enough and not absorbed onto the injector or column.

Keep water away from the anhydride (do you dry the acetone?) and it should be stable enough to perform an area analysis. But you will get 1% variation in area using a splitter. Is this good enough? perhaps an ISTD should be used? Research should be performed.

You might consider a 50% Phenyl phase and dissolving the sample in a silylating reagent to test for stability issues. Use a weaker reagent over a stronger one like the strong BSA or MSTFA.

best wishes,

Rodney George
consultant

Drying the acetone, good idea - wish I'd thought of it. I have some dry 3A mol sieves in a dessicator that should work.

Thanks for the information.