Recently I stained mitosox for evaluating mitochondrial ROS under palmitate treatment and found 2 peaks of mitosox signals (flowcytometry). I checked the staining by fluorescence microscope and found some dead cells were stained evenly in the whole cell, and some live cells were stained with mitochondria pattern, which might explain why I have 2 peaks. Now my question is: We used mitosox for evaluating mitochondrial ROS, should those cells with whole cell staining be considered as correct staining?