Yes, Dihydrorhodamine 123 (DHR123), a Rhodamine-derived indicator can be used to investigate reactive oxygen species (ROS). Dihydrorhodamine 123 is a fluorogenic dye that is useful for detecting ROS species by passively diffusing across the cell membrane where it is oxidized to cationic rhodamine 123. It will then localize in the mitochondria and exhibit a green-colored fluorescence.