May be the quantity of the lipid extract you used for methylation is too small ?

Should be the problem Teodora refer. Try using spliless injection, bigger injection volume.

... Or just concentrate the sample before injection.

Hi Teodora,

Is your injector temperature High enough? I don't know the column, but I think you use a specified method? Usually you don't have to change to splittless, this will require a complete change of your system. You can change the detector settings in the peak amplification , smaller damp number means higher sensivity, a sample concentration of 1% total is absolutely ok for a regular Split-Analysys 98:2% ...you can change there to 96:4% if the change in the detector sensivityi s not giving a satisfying result

Hi Frank,

In fact it is Mohammad who is asking the question about the small peaks. What I can suggest is that he have used relatively small quantity of the lipid sample to obtain methyl esters. But there is a lot more reasons. Unfortunately eh does not give us more details about the methods of extraction, esterification, temperature program, etc., so that we could help him.

Review your method of sample preparation, column conditions like temperature, pressure etc and leakage if there is any in the system.

concentrate your samples, ex: flush with N2 gas, then you can take good peak

First, split the entire process into extraction issue and instrument issue. Inject a neat standard by itself, or an internal standard with the neat standard, at the approximate concentration you expect to see. If you don't see peaks, the split the instrument issue between the chromatography side and the detector side. Are you using a liner with glass wool? Injection temperature appropriate (too hot or too cold?), Elution time long enough? Then adjust the parameters with sensitivity. If you are able to get sufficient peak resolution and signal with neat injections, but not your extractions, then make sure your extraction parameters are correct? Why type of extraction are you using? L/L, SPE, etc? If your extraction involves ammonium hydroxide, make sure it is fresh.