²⁹Si NMR measurement using silicon free probe

Standard materials used in NMR probe construction, as well as normal NMR tubes, inevitably contain silicon which is visible as abroad peak in the spectrum. As this is due to a Q⁴unit, it will overlap at similar chemical shifts to Q³ and Q⁴ units in any sample being measured. The use of a silicon free probe and suitable tubes completely suppresses the background signal and even small signals can be clearly seen.

²⁹Si spectra without sample

Actually measured data