This is an issue we considered a long time ago.
We intentionally ran the bonding Reaction at high Catalyst Concentration in order to actually reduce some of the Pt and Deposit it on the Surface. This produced a Visual Confirmation as the surface became Gray. Next we ran some Compounds that we knew would interact strongly with Pt and were able to observe longer Retention and most Important very Distinct Peak Tailing.
Finally we determined the %Pt on the surface by ESCA Spectroscopy was close to 1 atom %. Then we went ahead and did our normal process. Of course the surface is very white under those circumstances. The compounds gave very good Retention and Peak Symmetry was virtually 1.0. Then we took the material and analyzed it by ESCA. There was no Pt detected on the Surface.
The limit of detection of our system was about 0.01 atom %. So we feel very confident that there is virtually no Pt present as determined by both ESCA and Chromatographic Testing.