title: Gas-liquid chromatography of methyl esters of natural penicillins.
mesh_terms: D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D003470:Culture Media / Q000032:analysis; D008745:Methylation; D010400:Penicillin G / Q000032:analysis; D010404:Penicillin V / Q000032:analysis; D010406:Penicillins / Q000032:analysis*
chemical_list: D003470:Culture Media; D010406:Penicillins; D010400:Penicillin G; D010404:Penicillin V