In contrast, the pre-coated permanent modifier, Rh, is only
lost during the final cleaning stage of the program in which maximum power is necessary to remove the
carbonaceous matrix. However, when Rh is added to the diluent, it is lost even during pyrolysis, and at a much
lower temperature. This explains why addition of Rh directly to the diluent yields no modification benefits, and
why periodic re-coating of the filament surface for the analysis is necessary.