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- Posts: 26
- Joined: Wed Aug 29, 2018 10:43 pm
I am working on adding EPA 515.3/4 to our lab and I am looking for any tips to improve resolution and tailing. We are running a 6890N/micro-ECD (instrument also runs 504, 505 and 552 regularly.) I've shot several standards at 5-50 ppb using a few different sets of conditions, working off those recommended in the method and by Restek. Resolution and peak shape have not been satisfactory, especially on the secondary column. (Standard is the Restek methylated chlorinated acid 16-compound mix with methylated surrogate.) Thanks in advance.
Current best conditions:
Agilent J&W DB-1701 primary column, DB-5.625 secondary
He carrier gas, constant pressure @ 15.4 psi
2 uL injection vol, double gooseneck Sky liner @ 225 C
Detector temp 290 C
Temp program:
70 C hold 1 min
20 C/min to 150 C, no hold
10 C/min to 280 C, hold 5 min