Jordan T O'Neal, Satoshi Matsuyama, Kai Sakurai, Kyota Yoshinaga, Yu Nakata, Chiho Funaki, Yoko Takeo, Takenori Shimamura, Makina Yabashi, Haruhiko Ohashi, Kazutaka Takahashi, Mari Shimura, Taketoshi Kodama, Takashi Kimura
We demonstrate quantitative, high-resolution imaging of oxygen and iron in a single centric diatom, Thalassiosira weissflogii, using soft X-ray spectro-ptychography (SP), capable of elemental mapping. The quantitative accuracy of SP is tested by measuring the oxygen mass of SiO2 microspheres. SP is then directly compared to scanning X-ray fluorescence microscopy by measuring the iron mass within the same T. weissflogii cell, demonstrating consistent distributions with similar spatial resolution. The oxygen mass measurement of the T. weissflogii cell shows significantly higher resolution compared with iron due to the large edge jump ratio, showing the potential for quantitative measurements of the mass of light elements, carbon, nitrogen, and oxygen, in a single cell.