The lab states fixation will lead to the dyes to leak in the cells. I do think the idea is always that fixation may possibly destruction mobile membranes. I did find a paper which describes fixation utilizing methanol or acetic acid, soon after staining that has a DCFDA spinoff. DCFDA https://2-fdck-hcl46812.sharebyblog.com/29163814/the-2-fdck-hcl-diaries