Chromatography Forum

Hello at all
My system is Varian 3900/saturn2000 coupled with Tekmar lsc3100 purge e trap, for 8260 analysis.
Recently we have much problem with IS peak: when we change the trap the peaks are sharp, but only after 100 injection they has big tailing. The trap is vocarb 3000, desorbed at 250°c and baked out at 260°C
Direct injection was good, so I think gc/ms area works fine.
The problem seems trap related, but we can't change a trap every batch!
Has anyone experienced similar problem?

Thank you

What type of samples are you runnng, drinking water or waste water? Traps used for drinking water analysis generally last quite a while, but when waste water is analyzed the trap sometimes becomes contaminated quickly, especially if there are light semivolatile compounds present.

Samples are drinking water. 100 injection seems to me unacceptable also for wastewater....

danicrd,

Three comments. I have seen a lot of variability with traps and sometimes you get a bad batch. Try a different lot number and your problem might go away. Also, water management is critical, especially if using a frit sparger which a lot of water methods use. With a frit you will load even more water. Therefore, look at a dry purge (or a longer dry purge), look at longer bakes, etc.... You could also test this by purging for a short time and looking at tailing since less water will be loaded. Finally, make sure your trap is installed in the correct direction.

Best regards.