title: Identification and surface removal of incompatible group II metal ions from butyl stoppers.
mesh_terms: D002021:Buffers; D002118:Calcium / Q000302:isolation & purification; D003460:Crystallization; D004349:Drug Packaging; D008670:Metals; D013499:Surface Properties; D015032:Zinc / Q000302:isolation & purification
chemical_list: D002021:Buffers; D008670:Metals; D015032:Zinc; D002118:Calcium