The mask from oil droplet segmentation was applied to the maps of trapped protein radicals measured via accumulation of the spin trap CAMPO-AFDye 647 (ex 640 nm). Next, the applied images were filtered to visualize only the accumulation of the CAMPO-AFDye 647 at the droplet interface. Filtered images were obtained by applying the segmentation mask from the oil droplets on the raw data. Then, to remove the background intensity from within the oil droplets, only the pixels with intensity counts exceeding 30% of the maximum fluorescence intensity from all segmented droplets were considered for further calculation. With these segmented images, the level of trapped protein radicals per droplet was determined by first summing up all the intensities per droplet and dividing it by the circumference of the droplet using the radius which we obtained from the area in pixels after segmentation.