Chromatography Forum

Hi there...

I am looking for sulfur application or method in LPG. or anything related to sulfur and LPG.

Thanx in advance


regards,
Alchemist

Not sure what type of column would be suitable but if you use an FPD detector then there would be no interferences from hydrocarbons, assuming they contained no sulphur.

GCguy

I would suggest that you or your company become a member.

http://www.gasprocessors.com/

best wishes,

Rod

Try ASTM D5504 and D5623 using SCD Antek Analyzer.

You may wish to review Bulletin 722P from Supelco concerning sulfur gas analysis and retention indices.

Free download on the internet.
http://www.sigmaaldrich.com/Graphics/Su ... 0/4481.pdf

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rodney.george@sial.com

I have actually been working all week on sulfur analysis... My company asked me to develop a GC method for the analysis of S6 and S8. I was able to detect around 50 picograms of sulfur on the ECD, but the results were not great, somewhat non-linear, and I wasn't sure if I was seeing S6 or S8 as I only got one peak even at 500 pg/uL.

I then used our Varian 3800 GC with Saturn 2000 ion trap for the analysis and the results were significantly better. I can detect 20 picograms/uL of S6, and 125 picograms/uL of S8, both in different MS/MS modes. I dissociated 192 m/z for S6, and 256 m/z for S8, both using non-resonant waveform MS/MS. Do you have an ion trap available? It is a great tool for this analysis. I used a 10 meter, 0.18mm ID column, 1mL/min helium flow rate, and the column oven parameters were 70C for 2 minutes, then ramped at 25C/min to 280C.

Good luck!! What sort of sensitivity are you requiring for the analysis?

-Aaron

I have been trying to analyse sulphur compounds in LPG on a GC with a sulphur chemiluminescence detector. However, I am having difficulty with quenching effects and interferences due to propane in the matrix. Carbonyl Sulphide is the peak most critically affected.

There is a retention time shift observed in Propane samples compared to that seen in Butane, Ethane or Nitrogen and the amount of shift seems proportional to the amount of propane in the sample (i.e. 50% propane sample shifts half as much as >95% sample).

I have tried columns such as the Restek RT-sulphur(micropacked) and GasPro (PLOT) which are designed for this sort of thing but with no success.

Any help would be appreciated.


Regards

Ash

A Carbopack B with 1.5% SP-225 and 1% H3PO4 80/120 in a fused silica coated SS column might be a good choice. I would use acid treated glass wool or quartz wool for enclosures or deactivated SS screens.

COS elutes before ethane on this column. Propane propylene are well separated.

See Supelco Bulletin 722P

best wishes,

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rodney.george@sial.com

Do you need to speciate ? Most refineries etc. do total Sulphur see
TS3000

How about a heartcut? A heartcut is a lot cheaper than an SCD and should be just as reliable. With a heartcut you could also change column phases to optimize separations along a number of different bulk samples. It would also allow you to use a wide range of detectors and it would certainly cut down on the amount of interferences.

Best regards.

The best column for Sulfur is a simple 60m x 0.32mm x 5um. This should give you the best resolution between peaks.

Maybe my question is out of topic but...
Can anybody say something definite about equimolarity of SCD? Manufacturers declare about it but I heard from some chemist that presence of H2S during burning reactions does not allow SCD to be equimolar. Does anybody have an experience of SCD equimolarity check?