Hi.

I am a beginner in GC-MS.
I work in a pharmaceutical company. This means
that daily we receive new compounds.
We have just bought a Varian GC-MS. The GC-MS
works perfectly with the test solutions but when
it comes to ours compounds I do not get any
results.
The compounds are typically

Basic MW 100-400
Diluted in DMSO.

Where are problems?
Is it because of: the compounds not suitable to GC
The solvent
The injector (wrong inserts)
Injector temperature
Column type
Column temperature

With the compounds/ impurities It is difficult
know about:

Polarity
MW
Structure (funtiongroups )
Bp
Volatile

So what I am hoping to get is a standard method
that works, some guidlinies, books etc...
With LC-MS I am using a standard method: C18-
column, reverse phase Ionparring. This method
solves nearly 100% of the problems. The only
problem is that some compound can not be
ioinisate, and therefore I have to use EI (GC-MS)

Kind Regar

Hi agin

I forgot to tell the GC condition that I have
tried

Injector:
Split 1:50 straight insert
300 C

Column:
20m 5%-phenyl
temp 60-320 C

Kind regards

Peter

A 20m capillary column may require a relative higher temperature ramp rate and a flow rate. Otherwise, the retention time is too long and the compounds elute after the MS stops recording.