Peak quality

[mstfa]

Hello everyone,
I am new here and I am vey glad that I found this place, hoping that someone would help me with my problem.

I make some analysis of pharmaceuticals, and I got a very poor peak for acetaminophen. This happens every analysis I make but with regards to acetaminophen only. This is SIM mode and acetaminophen two ions are monitored between 11.05 and 11.50 minute.
http://imgup.pl/di/M9S3/acetaminophen.jpg

Could you please give me some ideas why is it happen? Is it the SIM method wrong, two few ions monitored?

[Peter Apps]

Most probably the tailing on the peak is caused by adsorption in the inlet or on the column. I cannot think how the SIM method could make any difference. Try changing your inlet liner, and if that does not help, trim 50 cm form the inlet end of the column. If the peak still tails try a new column.

Peter

[mstfa]

Thank you very much! I really appreciate your response.

I changed the derivatizing agent for trimethylsililation instead of tert-butyldimethylsililation and it is much much better. But I have also different SIM method for this derivative, so I wondered if I made the wrong method before. Thanks for your suggestion.