A rapid and efficient preconcentration method was developed for the determination of trace metals in water. Trace metals [e.g., Ni (II), Cu (II), Ga (III), Cd (II), Pb (II), and Bi (III) ] in 1 dm3 of sample solution were converted into the hydrophobic chelates with ammonium pyrrolidinedithiocarbamate. The resulting metal chelates were extracted into admicelles (silica particles covered with cetyltrimethylammonium chloride), which were floated with numerous tiny bubbles to the solution surface. The floated admicelles were collected in a small sampling vessel by suction and the metals were eluted from the admicelles with dilute nitric acid. A 200-fold multielement preconcentration and subsequent determination by inductively coupled plasma-mass spectrometry were achieved within 30 min. The proposed method was applied to the analysis of river water.