For each simulant recovery check samples were prepared equally. Simulants were fortified to 100 mg l1 titanium by
adding 0.1 ml of the 100 mg l1 titanium containing Merck XVII standard in a 100 ml volumetric flask and filling it up with the respective simulant. The recovery check samples were then transferred into Erlenmeyer flasks and stored under the same conditions as the migration samples, with the same subsequent sample work-up procedure. The detected amount of titanium was compared to a freshly prepared 100 mg l1 standard in 3% nitric acid. Both, the migration samples and the recovery check samples were done in triplicate.