Lux Amp Series: How often should I make new mobile phase? Do I need to make completely new mobile phase or can I keep adding new mobile phase to the old mobile phase?

1. Since Ammonium Bicarbonate is a volatile buffer it is best to make new mobile phase every day but we have found that this buffer is stable for as long as 2 days.
2. It is best practice to make completely new mobile phase every time and not to keep adding the old to the new mobile phase.