Sounds not very likely – it’s quiet a high carbon background in an ICP – normally people use gas source IRMS instruments for carbon and oxygen isotope work.
Thank you Daniel, since we need to do some high-resolution sampling with the microfossils, and we'd like to have a try with the laser ablation as an option, probably the micromill technique is enough.
At present and in the future, we won't be able to measure C, N, H, O, A, He isotopes using ICP-MS with or withour Laser .... "impurities" in the gases we use to have a plasma and as carrier gas for transport of th aeresol, will prevent this as well as the inefficient ionization of these elements...
Perhaps someone disagrees, I would be interest to learn about it....
Maybe you could check publications by Sharp and Cerling, (e.g. Sharp, Z.D., Cerling, T.E., 1996. A laser GC-IRMS technique for in situ stable isotope analyses of carbonates and phosphates. Geochimica et Cosmochimica Acta 60, 2909–2916), they work with IR Laser hyphenated to GC-IRMS (and not ICPMS indeed)...