Dear all,

Does anyone have the experience in reducing the peak tailing's problem of methyl ester running in GC column. I try to analyse some methyl esters and find a significant peak tailing using 5% phenyl column. Please advise.

Uberto

What other functional groups are unblocked? None? then:

poor capillary column installation can cause tailing.

A packed column should not have tailing unless there is a void internally in the column.

My guess from your terse description is column installation.

We use SP-2330 from Supelco for fatty acid methyl esters, no tailing.

Most analysts use a more polar column for methyl ester, especially methyl esters of low molecular weight acids. A wax type column is one of the most commonly used columns for methyl esters, although for FAMEs a 5% phenyl column should give acceptable results.

Methyl esters are amongst the easiest compounds to analyse by capillary GC, and you should have no problems with a 5% phenyl column. If you have some alkane standards, you could try analysing these since they are even easier than esters. If you still get tailing, then you either have poor
column installation or a dead column. If you get good peaks with alkanes but bad peaks with esters, you could have a dirty inlet-what injection technique are you using? Try cleaning the liner. If this doesn't work, then your column is bad-try breaking off the first half metre and see if it improves the performance. Contamination is always worst in the first section of the column and you may cure the problem completely.

One very basic thing is the derivatization. Are you sure that you are really analyzing methyl esters? If your esterification is not complete and you are analyzing acids the peak shape will be terrible.