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High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 3:33 pm
by nicmendola
Trying to resolve problem with vinyl chloride failing % RSD. Response factors decreasing with increased concentration. Any ideas?
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 3:38 pm
by tkubowicz
Hello
You didn't write anything about method:
-parameters for GC
-sampling technique - Purge and trap?
More details you give, quicker answer you'll get
Regards
Tomasz Kubowicz
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 5:24 pm
by dblux_
Trying to resolve problem with vinyl chloride failing % RSD. Response factors decreasing with increased concentration. Any ideas?
What is your main problem, RSD or response factors ?
Relevant details neccessary if you want anybody to devote time for your problem.
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 5:45 pm
by nicmendola
The main problem appears to be the decreasing response factors which is causing the %RSD failure. We are getting linear curves for all gases, except for vinyl chloride. The responses for vinyl chloride are linear for the first 3 calibration points and then start declining from the midpoint to the highest level.
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 5:47 pm
by nicmendola
Sorry for lack of details. I will post them next. Thanks.
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 6:35 pm
by nicmendola
Running Purge & Trap Tekmar ATOMX autosampler, 5mL purge volume, 11 min purge time and Supelco "K" trap VOCARB 3000. Agilent 7890B GC and 5977A MS with Agilent J&W DB-VRX 20m x 0.180mm x 1.0um column. 50:1 split ratio, Calibration range 5 to 200.
Re: High Percent RSD for vinyl chloride
Posted: Fri May 06, 2016 6:42 pm
by dblux_
EPA 524 method accepts quadratic regression. Will this help to get acceptable RSD for vinyl chloride ?
Re: High Percent RSD for vinyl chloride
Posted: Wed May 11, 2016 12:40 pm
by Bigbear
Using the 6mm draw out plate? BFB_Autotune? Dry purge?
You should consider upping the split to 150:1.