Polypropylene screw top vials (Item# 9502S-PP-CLEAR) are not tested for metal content. However, we would expect it to be low since metals are not used in the manufacturing process. Since the vial are not tested and after opening the package in environments with metals we can’t guarantee the vials to be metal free.
Screw top caps (Item# 9502S-30C-B) are manufactured free of sodium, potassium, magnesium and calcium.
If you wish to determine with certainty the absence of these metals, we would recommend sending samples to a third-party commercial laboratory that can perform ICP or ICP-MS analyses.