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Pesticide analysis questions (maintenance-related)
Posted: Wed Jan 31, 2007 5:30 pm
by chemwipe
For anyone in here who does pesticide analysis - do you have to do GC maintenance before each batch?
I regularly cut 1' - 2' from my guard columns, change my Presstight connectors, change out my liners and maybe once a week change my Siltek baseplates.
Anyone else do this on the daily? Just curious.
cw
Posted: Wed Jan 31, 2007 7:38 pm
by vballchemist
This sounds familiar. Prior to each analytical batch we go through the same steps to ensure low breakdown.
Posted: Thu Feb 01, 2007 7:26 am
by kdamme
In our environmental lab:
We have on-column injections and change guard columns every +/- 2 days (50 samples) for ground-samples.
Groundwater samples are analyzed with large-volume injection with a guard column and a few metres of analytical column before the "real" analytical column. The guard column and few metres of analytical column are changed every +/- 2 weeks (70 samples).
For both systems: pesticides are still fairly good before the guard column is changed, but we also analyze PAH on these GC/MS and they tend to tail much earlier...
We have replaced the press-tight connectors as much as possible by a metal connector and ferrules. In our opinion this gives less leakage problems.
Kevin