Hi everybody!

I run fame analysis with GC-FID and with DB-23 column 60 m.
I use Iso 12966-2 (rapid method) as sample prep:
0.1g extracted fat
+2ml isooctane, HPLC grade
+ 0.1ml transterification agent
+2 ml sodium chloride solution
+ 1g of sodium hydrogen sulfate monohydrate at the extract. *the method requests for sodium hydrogen sulfate anhydrous.
+ injection
It has come to my attention that the baseline rises at the end of the chromatograph and the retention time drifts continuosly. Furthermore, the resolution between some pairs is lost.
I changed the liner and the septum but the problem continues to deteriorate.
Do you hane any suggestions?