Hi all,

Currently I faced a problem when analyzing diethylenetriamine (DETA) with Agilent 7890 coupled with Agilent DB-5 column.

I have reviewed the forum and found one similar topic “Agilent 6890 GC analysis of diethylenetriamine”. But my problem is that the DETA peak is unstable with tailing.

At first, we injected high concentrated DETA in five replicates to passivate (saturate?) the liner (SGE, Tapered focus Liner, deactivated) and then injected the DETA STD (including internal standard, dodecane) in six replicates to evaluate the system suitability. The peak area is about 1200k with tailing and RSD is 4%. However, after 8 hours, the DETA STD was injected once to check system and the peak area dropped to about 600k while the dodecane peak area maintained the same level.

According to the previous topic, it seems that DETA was "trapped" in liner or somewhere else due to the basic amine group. I was wondering that if there is any solution to solve my problem (such as chromatographic parameter change and GC system PM) except the use of pyridine mentioned in previous topic. Thank you very much. I’d appreciate your help.

sisay