PIXE application for multi-element analysis of marine micro-algae and measurement of the concentration factor of zinc

Marine micro-algae (Nannochloropsis sp., Phaeodactylum sp., etc.) wereobtained from the Pacific Ocean off Iwate Prefecture, Japan, and culturedpurely in nutritive seawater, PES and artificial seawater, ASP7 as a culturesolution. The algae in 5 ml of the culture solution was collected on a polycarbonatefilm (pore size : 1.0 µm) by suction filtration. The algae on the filmwas subjected to PIXE analysis. A 2.9 MeV proton beam bombarded it at 50 nAfor 15 minutes. Induced X-ray was measured by Si(Li) detector. Concentrationsof Na, Mg, Al, Si, P, S, Cl, K, Ca, Cr, Mn, Fe, Cu, Zn and Sr were determinedsimultaneously. PIXE can used for multi-element analysis of a sample below1 mg, so the culture size for algae was 10–250 ml and every apparatuswas small and of low cost. Nannochloropsis sp. was given a different culturesolution (PES) including Zn²⁺ from 0.050 to 1.0 mg/l and incubatedat 22 °C, 2000 lux for 10 hours. Zn in Nannochloropsis sp. increased inproportion to the Zn²⁺ concentration in the culture solution. Theconcentration factor was given as 1600 500 (dry weight base). It was shownthat PIXE was a powerful tool for multi-element analysis of micro organismsand the measurement of bioaccumulation.