Chromatography Forum

Hi

I am a new chromatographer and haven't acquired any proper training on the technique other than things I learned all by myself and read up a lot but I would like for someone to explain to me what method integration is for Diesel Range Organics and what would be the best to use for calibration, Diesel or the Diesel Range Organics Reference standard

Thanks
Gugu

We no longer do DRO analysis but when we did we would integrate/calibrate a straight line from the solvent front which was then cut with droplines for a RT window between C10-C28 and then subtract the Surrogate value from the total area. I am assuming you will be using a FID?

I am pretty sure we used the DRO 50PPM standard for calibration and CCV but we used the reference standards to build a library of different patterns to different DROs like gasoline, jet fuel, motor oil, etc. because we used to also run PETID.

Hope this helps.

Hi

Thank you. It does give me an idea, I use an MS though which is not quite the best option for the DROs

You will have less sensitivity using the mass spec versus and FID, but it can be done. I have to use a mass spec when doing our GRO methods.

If you are using Agilent Chemstation, you set the Quant signal to TIC instead of Quant Ion, so that you are integrating the total chromatogram. I just integrate a flat line under the total set of peaks in a Diesel Standard. It depends on which state you run the samples for as to what the C-n limits are in the range. Some go all the way to C40, others C28 and others somewhere in between.

I try to use a local source of fuel and compare it to a purchased blended standard such as the ones from Restek, they usually compare quite well to each other.

Thank you very much James. The part about the sensitivity is true. I think another thing that gives me problems a lot on the machine is that I operate 5 methods which are DROs, GROs, Phenols, THMs and PAHs on the same machine. The source is constantly contaminated and a whole lot of other problems occur within it. I work with what I have though so it's fine for now.

Thank you once more.