can a split+FPD analyze trace sulfur in hydrocarbons?

[jf]

I came across this paper which describes analysis of sulfur in diesel fuel by a special instrument using an FPD:

http://library.abb.com/global/scot/scot ... -JM-BJ.pdf

can a 5890 with a split injector and FPD do something similar to this method? we only need a resolution of +/- 5 ppm.

I've never used an FPD before

thanks!

[CE Instruments]

The paper presented is not really a Gas Chromatographic method. It is really a Combustion Elemental Analyser but instead of using UVF detection they have used a GC Flame Photometric detector. There is as far as I know no advantage to this method compared to the UVF method as it will be less sensitive and will not result in a lower cost instrument. The selectivity of the FPD may not even be as good as UVF as Nitrogen (used as a Cetane enhancer) is a known interference for UVF
See UVF elimination of Nitrogen interference
for details of the problem and a solution.

You could use the GC method but Splitless for looking at Sulphur containing compounds by using an FPD after speciation by the GC method. The limiting factor with this is being able to see the very low level Sulphur compounds by FPD once separated. This is why Chemiluminescence is the recommended detection method being much more sensitive than FPD.

Do you have an FPD on your 5890 ? If not then abandon any thoughts now as you would be better off getting a suitable instrument rather than investing in an FPD for your 5890 and hoping that you can meet your detection criteria.

If you want to send me your e-mail address to Richard @ ceinstruments.co.uk I can forward you a few of the pdfs with methods for carrying out this work. (Remove gaps in address )

[AICMM]

jf,

Do you want to do speciated sulfur or total sulfur? If speciated, the FPD presents many problems including different response factors for different sulfur species, non-linear calibration and hydrocarbon interferences. If you want to do speciated, then SCD is a better alternative even though I have heard it too is subject to hydrocarbon interferences (not nearly to the extent of the FPD.) Unfortunately it is also more expensive. Having said that, you could still connect an SCD to a 5890 with an analog input board if your budget is tight.

If you are looking to do total sulfur, then the other issue you face is the combustion of the entire sample so that you end up with SO2 for the FPD to detect. This is not a trivial process but it can be done as evidenced by the ABB unit.

If you are only looking for one or two sulfur compounds, the game is completely different.

Best regards.

[jf]

i wanted to do total sulfur screening at the 1-50 ppm level. a usd instrument i was looking at had an fpd on it, but alas its gone now.