Rapid monitoring of 241Am in small amount of sediment samples by combining extraction chromatography for highly efficient separation of interfering and matrix elements and ICP-MS/MS measurement

•241Am was measured as AmO+ by ICP-MS/MS with O2 as reaction gas.•High separation factor (>2000) of Am/Pu by the instrument was obtained.•Extremely low background signals for the polyatomic interferences was achieved.•Rapid and easy chemical procedures for the separation of 241Am from solid samples were established.•241Am in sediments collected from the western North Pacific were analyzed for radioactive assessment.