The lab claims fixation will cause the dyes to leak in the cells. I believe the idea is usually that fixation may well harm cell membranes. I did look for a paper which describes fixation employing methanol or acetic acid, soon after staining which has a DCFDA derivative. DCFDA is https://1v-lsdblotters225mcgvaler93680.gynoblog.com/28907845/the-2-fdck-hcl-diaries