High BEC in H2 Mode for Silicon

Hi. I don't have much experience with silicon analysis but I recently read an article where methane was proposed as reaction gas to eliminate common interferences. For lower BEC you need much lower background signal. Probably avoid glas/quartz in the sample introduction. I don't know what your sample matrix is, but if it contains nitrogen you already have a problem on m/z28.

14N14N and 12C16O are common interferants.

hi carwogill, thanks for the insights.. im analyzing in organic mode and am using xylene as solvent, with 10% ISTD. your correct about the interferences by the N2 and C2H5+. Any ideal settings for the sample depth, neb gas, extract 1 & 2., and tuning masses as well?

thanks

No, I'm sorry I never analyze Si myself because I use nitric acid in sample prep and quartz introduction system :-( .Therefore I can't give you advice on settings.

But I think that using xylene you will have a big CO interference which you have to eliminate somehow.

When I tried Si, in the past, I used Sc as internal standard. In the article I mentioned before they used Ge as ISTD.

If you want only to analyze for Si it's probably best to tune mz28 and get the highest counts there, and to minimize counts on that mass with the blank xylene.

thanks! i appreciate the help

What type of sample intro kit are you using?

just for the information. I have solved my BEC issues by:

1. Since that my sample matrix is xylene, the most probable interference that I am facing is the N2 and the C2H5+. 
2. Increasing the Option gas, increasing the Energy Discriminator, increasing the H2 flow and Sample Depth, help to achieve the background of <10 ppb.
3. Option Gas, helps a lot in converting the N2+ (mass: 28) into a different species that does not interact in Si.


thanks