552.3 inlet degradation of analytes

[montucky1]

has anyone run into analyte degradation in the inlet of your GC? Had the method optimized for a quick runtime, but there were a few caveats and the SOP was getting a little difficult so i went back to the method suggested oven program and gained MCAA and lost DCAA... Any ideas?

[jdezeeuw]

This happens many times. With pesticides, carbamates, flame retardants..

If decomposition happens in teh LINER you need to eliminate Glass wool (take a double gooseneck or a cyclosplitter), Use LOWER injection port temperatures (using splitless injection you can us eMUCH lower temperatures as you inject during long time), or use PTV or even better: cold -on-column.

If decomposition happens in the column:(you can see by peak-shape): Make sure we minimize elution temperatures by:
Using Highest flow rate , Flow programming, columns with THIN films, SHORT length and preferrable H2 as carrier gas.
For instance for the BFR's we developed a special "fast" columns based on EPA1614.

rgsd
jaap de zeeuw, Restek corporation