Why is hepes buffer (conc. range 10-25mM) not maintaining RPMI 1640 medium pH with HL-60 cells?

Hi all, So my CO2 incubator broke and I have added hepes buffer to maintain my HL-60 cells which are in RPMI 1640 medium with 10% FBS. However the medium turns purple within a couple of hours. I...

22 March 2017 1,957 2 View