Fig. 3.

3D-surface MALDI MS imaging of A. curassavica leaf. Both samples were injured twice at a different time interval before harvesting. a, d Optical microscope image of the leaf surface after measurement. The injured areas are marked and associated time interval is indicated. b, e Topography image of the leaf surface showing height differences up to 500 μm and 600 μm, respectively. c, f RGB overlay of ion images showing the spatial distribution of calotoxin (m/z 587.2250, [M + K]⁺, red), dihydroxyflavone (m/z 255.0652, [M + H]⁺, green) and m/z 255.2110 (blue). MS images were generated with c 111 × 111 pixels, 45 μm pixel size, f 112 × 103 pixels; 35 μm pixel size; c, f m/z bin width: Δ(m/z)/m/z = ± 5 ppm. The scale bars are 1 mm