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- Posts: 1
- Joined: Thu Dec 14, 2017 10:27 am
Hi, my name is Albert and I've been recently promoted to instrumental manager in a small laboratory.
I had an instructor (the old manager) for a year before he left the job, so I'm facing with my lack of experience many problems that maybe are easy to solve for an expert but not for me, so I hope you can help me.
Actually my main problem is with the GC-MS (Agilent 7890A with MS 5975C and GC Autosampler 120).
In headspace mode I inject diferent samples with internal standard for the analyse of volatile compounds in water. Everything was ok until few weeks ago when suddenly, after few samples, one of the two ISTD I use dissapeared from the chromatogram (not at all, but I can see a signal wich is a bit bigger than the noise).
As I have told you, in the firsts samples I can see perfectly the two ISTD which are very stable. So any ideas for whats going on?
Something similar also happens with other analytes from the spiked sample, that doesn't appears in the spiked one or appears twice the concentration I've spiked (compared with the non spiked).
Thanks
I had an instructor (the old manager) for a year before he left the job, so I'm facing with my lack of experience many problems that maybe are easy to solve for an expert but not for me, so I hope you can help me.
Actually my main problem is with the GC-MS (Agilent 7890A with MS 5975C and GC Autosampler 120).
In headspace mode I inject diferent samples with internal standard for the analyse of volatile compounds in water. Everything was ok until few weeks ago when suddenly, after few samples, one of the two ISTD I use dissapeared from the chromatogram (not at all, but I can see a signal wich is a bit bigger than the noise).
As I have told you, in the firsts samples I can see perfectly the two ISTD which are very stable. So any ideas for whats going on?
Something similar also happens with other analytes from the spiked sample, that doesn't appears in the spiked one or appears twice the concentration I've spiked (compared with the non spiked).
Thanks
