I would like to ask for protocol for cell culture samples preparation for HPLC. I am going to measure antioxidants levels in adherent cell cultures. I need to precipitate proteins and I should do it by 90% acetonitrile + 0.1% TFA (according to my boss).
I just don't not how much acetonitrile to add to cell pellet, how long to vortex the mixture, keep on ice or not, what speed to centrifuge etc.
Second question, can I freeze these acetonitrile samples in -80°C and for how long?
Thank you for any comments!