Headpace-methylation will H2SO4 in vial damage GC?

[MSCHemist]

cranking it up to 185 seems unnecessary and produces a large peak of dimethyl sulfate and also pushes the static head pressure. Looks like I'd also need to go back to a wax column (I had in the db5 thankfully or the DMS would have really boned it) in order to retain methyl acetate sufficiently.

[MSCHemist]

I've finished evaluating the method. It works pretty well though responses drop off after C10 acids. The best conditions are 1part 1N H2SO4 to 1 part alcohol (i use 9.2ml vials with 5ul methanol and 5 ul H2SO4) (I use methanol as ethyl esters are pretty ubiquitous in flavors). Thermostat at 1 hour during the GC run at 120 deg C; 150 deg C loop and transferline. DO NOT use saturated bisulfate as I tried that and it worked very poorly compared to 1N H2SO4 it was the only time I saw free acids on the GC chromatogram the efficiency was so low. Overall it has merit though I think I prefer my isobutyl chloroformate in isobutanol/pyridine/0.1N aqueous NaHCO3 method the best.

I wish there was a better way to do citric and tartaric than silylation or imperfect chloroformate method.

[Peter Apps]

Thanks - good to know.

Peter