Purge e Trap

[danicrd]

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

[Ron]

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.

[danicrd]

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

[AICMM]

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.