Hello

look at links here will help you

Good Luck

http://medicine.yale.edu/labmed/cellsorter/protocols/staining.aspx

http://www.ebioscience.com/resources/best-protocols/flow-cytometry-protocols.htm

http://flowcytometry.uchc.edu/pdfs/protocols/cellstaining.pdf

http://services.medicine.uab.edu/PublicDocuments/ImmRheum/FACS%20sorting%20protocol.pdf

You need to establish a good validation protocol that includes a viability stain in your stained tubes. Washing buffer is important, I suggest to use colorless RPMI media. I also suggest to validate fixation before and after staining. 

Hi, So have you done this? I'm going to stain my samples after sort so I wonder if you found a method to do so.