HS GCMS method for determination of volatile extractables in 50:50 EtOH:Water extract

Extractables and Leachables Analysis | Agilent

5989_5672.qxd (agilent.com) -- "Most of the compounds identified were specific to high-temperature headspace sampling or solvent extraction techniques. The MMI in solvent vent mode allows for the detection of low-level leachable/extractable compounds by making large volume injection. Headspace sampling simplifies sample preparation as the pMDI component can be placed directly into the headspace vial for analysis."

The EtOH/Water mixture would work better injected as a liquid sample than as headspace. In the headspace, you need enough temperature to help the peaks of interest into the gas phase but not so much that you vaporize the binary azeotrope of EtOH:Water at 78.1°C.  Reducing the volume of sample in the vial will help, but at the cost of sensitivity of your target compounds. A 1uL liquid injection would also reduce sensitivity, so injecting a larger volume into a MultiMode Inlet in solvent vent mode would help.  Reducing the incubation temperature will help, but possibly at the reduction of sensitivity of your target compounds again.  

I would suggest some consultation with Agilent Application Engineers. One place to start in the US is: 800-227-9770, option 1 for sales, then option 1 for Consumables, Columns, and Supplies. 

Extractables and Leachables Analysis | Agilent

5989_5672.qxd (agilent.com) -- "Most of the compounds identified were specific to high-temperature headspace sampling or solvent extraction techniques. The MMI in solvent vent mode allows for the detection of low-level leachable/extractable compounds by making large volume injection. Headspace sampling simplifies sample preparation as the pMDI component can be placed directly into the headspace vial for analysis."

The EtOH/Water mixture would work better injected as a liquid sample than as headspace. In the headspace, you need enough temperature to help the peaks of interest into the gas phase but not so much that you vaporize the binary azeotrope of EtOH:Water at 78.1°C.  Reducing the volume of sample in the vial will help, but at the cost of sensitivity of your target compounds. A 1uL liquid injection would also reduce sensitivity, so injecting a larger volume into a MultiMode Inlet in solvent vent mode would help.  Reducing the incubation temperature will help, but possibly at the reduction of sensitivity of your target compounds again.  

I would suggest some consultation with Agilent Application Engineers. One place to start in the US is: 800-227-9770, option 1 for sales, then option 1 for Consumables, Columns, and Supplies.