Bio-Rad ChromLab™ Software - Manual (Page 138)

5 | Method Editor
136 | NGC Chromatography Systems and ChromLab Software
Available Range — available ranges for the recipe concentration and pH values
vary depending on the recipe you choose. The ranges provided are
recommendations. You can choose values above the upper end of the range, but
doing so might require other adjustments to ensure accuracy. For most recipes you
can change the buffer concentration by reducing the stock concentration by 1/2 to
1/8 on Conjugate Acid/Base Pair titration and up to 1/4 on Acid or Base titration.
Stock concentration for most recipes is 0.2 M.
Tris and Phosphate are the most commonly used recipes, depending on the type of
chromatography being performed.
pH Correction — used to correct the observed pH so it matches the pH set for the
run (Desired pH) in the System Pump dialog box or Method Settings phase. pH
correction uses the difference between the desired pH and observed pH to make
the correction.
Tip: Calibrate the pH probe regularly for accurate pH reading.
Phase Controls and Parameters
The Method Editor includes several standard phases. See Standard Phases on
page 138 for details.
A phase is a method segment composed of a discrete block of steps created to
accomplish a specific task. Each phase comprises controls and parameters specific
to the task it is designed to accomplish.
The controls and parameters used in individual phases are as follows:
 Gradient Segments — determine the length and buffer composition (%B)
for isocratic or gradient steps.
Tip: Each phase runs at a single flow rate. To change the flow rate, select
a different phase.
In isocratic steps, initial %B and final %B must be equal. In linear segments,
initial %B and final %B are independent of each other.