Bio-Rad CHEF Mapper® XA System - Manual (Page 12)

3.1 Auto Algorithm
This example outlines the steps for separating a DNA sample with a size range of
220 kb–2,200 kb (the size range of S. cerevisiae).
1. Press AUTO ALGORITHM.
2. After Molecular Weight: Low, key in 220, press K-BASES, then ENTER.
3. After Molecular Weight: High, key in 2200, press K-BASES, then ENTER.
4. The lower line will display Calibration Factor [ ], enter for NC (= no change). This
factor alters the run time by the factor entered between 0.1 and 9.9. Press ENTER for
default of 1.0. The lower line displays the physical parameters for the run: 0.5x TBE,
14 °C, 1% PFC agarose. Press ENTER.
5. The screen display shows the calculated electrical parameters: 6 V/cm, Run time= 28:59 (hr),
Included angle 120°. Press ENTER or the down cursor key three times to reach the end
of the screen.
6. The electrical parameters continue on the next screen: Int. Sw. Tm = 26.31s, Fin. Sw.
Tm = 3m48.48s, Ramping factor: a = [ Linear]. The first two entries are the calculat-
ed initial and final switch times. Since the times are different, the CHEF Mapper system
has selected a switch-time ramp. Press ENTER or the down cursor key to move the prompt
past the variables.
7. The final display is A program is in memory. Start the run by pressing START RUN.
3.2 180° FIGE
1. Press 180° FIGE. The message You will destroy last program - Go on? is displayed.
Enter 1 for yes. This removes the last program in working memory. It does not erase any
stored programs.
2. After Forward Voltage Gradient = [ ] V/cm, press 9 and ENTER.
3. After Int. Sw. Time =, press 90, then SECONDS, then ENTER.
4. After Fin. Sw. Time =, press ENTER.
5. After Rev. Voltage Gradient = [ ] V/cm, press 6 and ENTER.
6. After Rev. Int. Sw. Time =, press 30, then SECONDS, then ENTER.
7. After Rev. Fin. Sw. Time =, press ENTER. This has set up a ratio of 3:1, forward to
reverse switch times and also differences between forward and reverse voltage gradients
(field strengths).
8. For Total Run Time=, type 24, then press HOURS and ENTER.
9. The final display is A program is in memory. Press START RUN. The unit will begin
switching, which is verified by bubbles emanating from the electrodes.
10. The display shows the status of the parameters during the run, including the run time,
time remaining, current, switch time, forward or reverse field, voltage gradient, ratio,
actual volts, and ramping factor. Press the up or down cursor keys to switch between dis-
plays during the run.
11. To stop the run, press START RUN and PAUSE/CONT simultaneously. Answer the
prompts by pressing 1, then ENTER.
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