Bio-Rad iQ™5 Optical System Software, Version 2.1 - Manual (Page 44)

Section 4 Workshop Module
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4.3.4 Gradient
A thermal gradient may be programmed across the reaction block at any step of a protocol. The
gradient runs from the back of the instrument to the front, with the hottest temperature in row A
and the coolest temperature in row H. All wells in each respective row are at the same
temperature so at any time during a gradient step, there will be eight different temperatures
across the block with 12 wells at each temperature. The gradient may be as large as 25°C or as
small as 1°C. The gradient is not linear, but is highly reproducible. No row can be at a
temperature higher than 100°C or lower than 40°C during the gradient step.
NOTE: A gradient cannot be applied to any step, which also has a melt curve.
Programming a Thermal Gradient
To program a thermal gradient:
1. Click Gradient in the Show Options box. Two columns will appear in the spreadsheet and
a representation of the gradient will appear on the right side of the window (Figure
4.14).
2. Click the Gradient checkbox in the spreadsheet for the desired step.
Fig. 4.14. The Protocol Editing Table.
3. The temperature listed in the Setpoint cell of the spreadsheet will be the coolest
temperature on the block during the gradient step (row H). Enter the desired difference
between the coolest and hottest temperatures during the gradient step in the Range cell
of the spreadsheet. The Gradient Display table (Figure 4.15) will update with the
temperatures at each row.
4. You can change the range in the spreadsheet or make a direct entry of the range in the
gradient display. Press Enter and the display will update with the new calculated
temperature for each row.
Fig. 4.15. Gradient Display Table.