We have a GC in our laboratory and I have been set the task of coming up with a preventative maintenance schedule for looking after its running etc.
Does anyone have any practical tips in keeping it tip-top?
I have alread started a list for operators to write down the nature of the samples they inject (it is a non-dedicated instrument) and I am recording how often the septa liner etc
By Anonymous on Thursday, June 12, 2003 - 09:08 am:
Make reference chromatograms with new columns for comparisons as column(s) age. Keep entire inlet clean, important. Clean FID detector at least once per year.
By Lucy on Friday, June 13, 2003 - 12:15 am:
By B.Mischke on Friday, June 13, 2003 - 07:14 am:
it's ok to clean an FID. But never change a running system! Keep the injector clean, change the septum after 50 injections per hand or 200 per sampler. Note in Your diary the FID signal level - to compare it. Normal is 5pA or in this range. I'm wouldt use N2 as make up gas and never He, the sensitivity decrease with He!
Calculate the "Theoretical plates" for a "nice" peak from time to time, so You will see any changings in efficiency. If You have more questions, ask me.
By Lucy on Sunday, June 15, 2003 - 11:02 am:
Wha is your p[referred method of calibration? Would you perform external calibration with internal standards (where appropriate)? Would you by a test solution, or use solvents based on ratio for response?
By Anonymous on Wednesday, June 18, 2003 - 12:04 pm:
Monitor gas flows and split flows periodically. Some instruments may drift which will change retention times.
Also, I use high purity gases or whatman generators for gas supplies. If using tanks, change them when they reach about 250psi, don't let them run too low or you may see baseline problems (or worse, they run out). Use indicator moisture traps, change them when 3/4 saturated. Change the O2 trap when moisture trap is changed.
Definitely change the septum like Mischke says.