Hi John,
I like your attempt to use MAN - collect MAN for various metals - which includes the contamination on those metals - and then subtract it, thus eliminating the need for a calibration curve and allowing phi-rho-z. I will have to give it a go!!
This method subtracts both the background and the contamination from each point. What do you think - do you think its as good as a calibration curve? Also do you think its as good as subtracting a set value for contamination and meansuring the background value to subtract?
Thanks
Ben
Hi Ben,
Let me make sure I understand your point. You are saying that if one uses a MAN background calibration curve for carbon measurements, then the natural carbon contamination rate would get normalized out in the background correction? Yes, this is essentially what happens when one uses the multi-standard calibration curve method for carbon analyses, but your idea would allow us to still utilize phi-rho-z, etc.
If this is what you mean, I have to say it might be possible. The only issue I can see is that the carbon contamination rate is somewhat dependent on the thermal conductivity of the surface. That is, the higher the thermal conductivity, the slower the cracking of hydrocarbons and subsequent deposition on the surface... therefore one might want to try and make sure that standards used for the MAN calibration are similar in thermal conductivity to the unknown material. For example, for carbon in steel, one might want to utilize pure metals rather than pure oxides for the MAN calibration...
It's worth a try. Please post your results here, or maybe even better, start a carbon measurement topic and put it there. I'd be very interested to see what you find.
john