title: Trace-metal contaminants in filter paper.
mesh_terms: D001463:Barbiturates / Q000032:analysis; D002118:Calcium; D005374:Filtration; D010209:Paper; D014001:Tin; D014131:Trace Elements
chemical_list: D001463:Barbiturates; D014131:Trace Elements; D014001:Tin; D002118:Calcium