Hi, we'd like to analyze an SPE extract whose solvent is methanol, with a GC-MS/MS (ion trap), split/splitless injector, and this column. The supplier told us about not to inject in this column anything with more than 5-10% polar solvent, because of risk of damaging the column, but several colleagues told us not to worry about this. Anyone has worked with this column and a solvent like methanol? Thank you.
methanol can be a problem if it is not properly dried, try a 3A molecular sieve to remove any traces of water. as long as you keep the column free of water it should be ok.
before eluting from the SPE cartridge it is also advisable to remove water with a stream of nitrogen.
Two issues here. 1) expansion volume, methanol will expand from 1 uL to 625 uL at injector temp of 250 C. If your liner has effective volume less than 500 uL, your sample will over flow to the split vent. 2) VF-5MS is non-polar similar to DB-5, methanol is too polar for this phase and will form droplets moving inside the column, resulting band broadening. You should exchange to more non-polar solvent with less expansion volume such as acetone or toluene. Check the solubility of your analytes in the solvent as well because it may no dissolve in acetone or toluene.
http://www.chromacademy.com/essential-guide/Aug_2012/fig-22.swf
Hi, fascinating comments, but I have a question. I'd like to realise an AOX (Adsorbable Organic Halogens) extraction with the SPE method, whose solvent is dichloromethane. I must analyse the extracts with GC-MS with a VF-5ms column (polysiloxane phenylmethyl to 5%). Is it recommendable to use dichloromethane, or is it better to use another solvent such as ethyl ether?
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