Chromatography Forum

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.

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.

Thanks - good to know.

Peter