Chromatography Forum

Well, after I succeeded in RT Locking my 5973 mass spec for my 8260 method; I went ahead and set it up for SIM/Scan. I got the 69 compounds including the ISS, in 21 groups. Have a fairly good cal and put vinyl chloride and the gases, DBE, and DBCP on SIM-ion and the rest of the VOC compounds on SIM-scan. Using SIM-scan gives about 35% more area counts on each peak compared to simple scan mode. I believe I specified a minimum of 12 points per peak. I had to manually split in half the cluster of compounds preceding and including Flurobenzene.

I have not done it yet; but I am pretty sure I can process the calibration files with my BTEX method and make a cal curve. However, because the BTEX method only has 17 analytes (and the same ISS). I would not be able to run the BTEX method and process it with the 8260 method. It seems to me I will have to run everything in 8260 mode and then process out BTEX if that is all the customer wants reported. That will be a little hard on the filaments because the 8260 method starts at 0.8 minutes (versus 1.6 minutes for BTEX), but no difference otherwise.

We run all of ours in the full list method and we have separate analyte lists setup in the LIMS and just let that sort out what the client wants. That way we can do full list, short list non Appendix IX, BTEX, TCLP or others all on the same run and let the LIMS spit out the proper reports.

I saved time and copied my G8260sim.m to GBTEXsim.m and deleted the 50 unneeded analytes. Reprocessing the files with GBTEXsim will generate my BTEX results and still gets the advantage of the RT Locking and SIM/SCAN peak areas.

Not so bad! I think our 8260 list is up to 135 compounds.