Bio-Rad ChromLab™ Software - Manual (Page 44)

2 | The NGC Instrument
42 | NGC Chromatography Systems and ChromLab Software
Buffer Blending Valve
The buffer blending valve is used for automatic online buffer preparation. The buffer
blending valve blends buffers to a specific pH using standard acid and base buffer
solutions. This enables automated pH scouting without manually preparing buffers
at various pH values. The buffer blending valve titrates the appropriate amounts of
the acid and base stock solutions to produce buffers at the required pH values.
Because salt concentration can affect pH, the blending algorithm takes into account
the salt concentration for accurate pH blending.
Stock solutions of four buffers are connected to the inlets. The buffer blending valve
can be connected directly into the inlet of the system pumps or to port 8/BB on the
buffer inlet valves. In addition to buffer blending, the buffer blending valve can be
used to double the allowed flow rate of a salt gradient (for example, up to 20 ml/min
on an F10 system pump and 200 ml/min on an F100 system pump).
The buffer blending valve can be plumbed to two buffer inlet valves, each
connected to seven different buffers. The system can switch between blending
mode and simple salt gradients without replumbing.