Chromatography Forum

I have a method that quantifies triethyl amine (TEA) using an Rtx-5 amine column and a FID. This method has worked very well in the past, but recently I have encountered difficulty detecting TEA in dilute standards. At less than 100ppm I get no peak. At greater concentrations, the peak tails. Other components in the standard, including less volatile primary amines behave normally. The column is approximately 3-4 months old and worked fine when it was new.

Any ideas what's going on here?

The method works well with high concentration,but it's the first time you apply it for low level and you don't see anything???

You may have contamination and/or activity in your liner and/or column,and -NH groups interaction with active surfaces results in peak tailing or reduced sized peak


1-Try to cut 10-20cm of the column,that should be helpful.
2-If you use splitless injection ,install a new liner if it is 4 month old as the column.

Bye

you know Restek has a base-deactivated liner ideal for amine or base compound test? Can try it as well.

I think the two suggestions above are good ones. The problem is almost certainly the activity of amines. We found that they would even stick to metal and glass surfaces (ie syringe, serum vials) while still in solution, decreasing the sensitivity, especially at low concentrations.

Do whatever you can to deactivate your system and hope for the best.

switch to a npd for amine analysis and yuo will get very good sensitivity