Other limitations / “issues”
In practice the HaySep-D is needed for CO2 separation but is somewhat limited for higher MS VOCs by column bleed and/or flow sensitivity drift of the TCD during temp programming to propane(?) EtOH, MEK for example at 180C max unless you use ultra pure He and/or Oxytraps
The HS-D can be replaced with capillary column for more detailed resolution of hugh MW or polar components but CO2 is then sacrificed !
Calibration of these is assisted by the on-column liquid injection porr fitted standard on the MG#5
The set up is somewhat convoluted and users need to understand the logic and peculiarities of the GC set-up re “Timed Events” of PeakSimple and multiple peaks etc !
Definitely NOT a “DO-All . . . Do everything” ! concept & NOT For GC BEGINNERS !
- For H2 an extended design of the MG#5 becomes too complex mechanically / re GC internal space etc
> a separate GC(s) using Argon carrier gas is recommended
For high concentrations of H2 a simplified GC / is suggested using a CCD Detector ( 500ppM LOD) with 1 cc sample size for H2, CO, H20, methane and C2 > but probably NOT CO2 or Air ( Ar/ O2/ N2 )
> much lower cost
- columns to be decided on MolSieve for CO fromHAir) and CCD Not suitable for capillary columns CO2 probably non-reponsive in CCD and no need to separate CO2 on HS-D; backflushing of the CCD may still be required and can suffer from over saturation (high %) ???
Not yet implemented or actually offered by SRI
On-Lne auto analysis of gases AND complex VOCs is fraught with difficulties particularly related to
“Headspace Gases Analysis” ( re sample size available from the process AND LODs and the need for more sophisticated GC Detectors
NO Equivocation here ! . . . Just stark reality
- Yes there are some answers here! > but . . . more complex, more expensive > ASK !