4% paraformaldehyde - (Jul/20/2011 )
When I created fixing buffer for my cells for immunofluorescence, I used 2x PHEM buffer at 1x but diluted it to 1x with PBS instead of water. Since 4% PFA buffer can be made with PBS too, do you think this will be a problem? I'm just worried that the cells might be unhappy with that mix of buffers.
Adding PBS increased the salt content so the cells might not be happy. You can easily fix in formaldehyde in PBS if you need to make more.