Hi all,

I am quite keen to get an expert opinion on our configuration, specifically the MS placement. We are looking to quantify permanent gases and all hydrocarbons up to 400 deg BP. We are actually trying to setup Py-GC-FID with Simdist and Py-GC-TCD-MS for chemical characterisation. but for making things easier we don't have to factor the pyrolyser. It might be helpful to draw this in a diagram to visualise.

Configuration 1:
- GC1 - TCD
- GC2 - FID - MS

GC1 will have a single column to TCD to analyse C1 - C5 and permanent gases.

GC2 will have a 100 m column then a T switch (not sure if its a dean's but don't think so). Then the products are split to FID and MS. The FID detector for a simdist analysis using a third party software (not calibrated at factory or dedicated for simdist. The MS will analyse >C5 for chemical characterisation.

Configuration 2:
- GC1 - TCD - MS
- GC2 - FID

GC1 will have a combined T connection and dean's switch, it will allow for pyrolysis products to be injected into GC from a different injector where a liquid sampler will be used This is important for us in calibration

Then one column before the dean's switch allows for fast transport of permanent gases and C1- C5 to be taken into a TCD via a second column after the dean's switch. While the rest >C5 is tested with MS.

GC2 will have a combined T switch similarly for the Pyrolyser and liquid injection.

Then a column connected to FID detector with an interscience simdist capability for ASTM 2887 (55 deg to 537 deg).

Supplier recommendation
The thermo fisher rep is saying that configuration 2 is optimum and configuration 1 is not providing accurate Simdist because its not setup from manufacturer and the 100 m column will cause challenges.
Agilent rep is saying configuration 1 is optimum and configuration 2 is faulty because we must use the GC-FID-MS instead of GC-TCD-MS.

We are conflicted and have been bouncing back and forth with suppliers. If someone can advice which configuration is more capable and why that would be appreciated.