Hi there. I am aware this is a weird question, but here goes. I would like to 3D print some small parts that will eventually be inserted in the measurement cavity of an ESR/EPR spectrometer. Polymers not infrequently contain free radicals left over from the polymerisation process which would interfere with the measurements. Does anybody out there know which, if any, of the polymers used in 3D printing end up spin-free? Many thanks in advance for the help.