What is your signal to noise ratio for the peak ?
If I calculate correctly 1ppm solution injected On-column would be equivalent to 100pg on column
From the specifications on a Thermo GC8000 from 1992 we had a signal to noise ratio of over 100:1 for 2pg on column for Chlorinated pesticides. If this is the correct quantity on-column it sounds as though either you have appalling reproducability or very poor sensitivity or a combination of both.
You do not state which chlorinated pesticide, not all have such a good response on ECD. To check the system I suggest you look to the manual find out the quoted performance specifications for the Clarius and then run the test standard. 8% rsd may be acceptable if you are running at minimum detction limits but 1ppm is not MDL for most Chlorinated pesticides.
For reference MDL Lindane 0.1pg on column ECD40/ECD400 in 1992
I am getting %RSD of around 8% for 1 ppm chlorinated pesticide using CLARUS GC with autosampler and ECD detector. Can anyone help me in deciding whether this much precision is OK or there is area of improvement