Introduction to the Agilent 7100 Capillary Electrophoresis System

5 Using the Agilent 7100 Capillary Electrophoresis System
Capillary Electrophoresis, CE
Posttime and Stoptime
The stoptime defines the time for your separation, also referred to as the run
part of the analysis. It does not include replenishment, preconditioning,
injection and postconditioning. After the stoptime has elapsed, the system
changes from the run state to postconditioning or postrun (if defined) and
then to the ready state.
The posttime is normally used for equilibration. It defines the time after the
analysis, that is after the stoptime has elapsed and data analysis is completed.
During the posttime the instrument is in the postrun state. After both
stoptime and posttime have elapsed the instrument completes
postconditioning and is then ready for the next analysis.
Replenishment
During multiple analyses, the composition of the buffer can change, for
example the pH due to electrolysis. A simple way to refresh the buffer is to
access different buffer vials in the tray which might be “user vials” in the
method that are assigned to a certain tray position in the sequence table. This
is more useful, for example, during method development.
Another way to change the buffer is replenishment. Replenishment can be
programmed via the topmost table in the right side of the CE Method Setup
screen. It is done either in parallel or serial to the subsequent conditioning
operation. The associated timetable can be used to empty, fill or replenish
vials to a certain height.
The replenishment system automatically empties and refills the buffer vials in
the tray with new buffer from the electrolyte bottle. Therefore, the number of
tray positions occupied by home vials is reduced and a maximum of sample
vials can be loaded. Typically replenishment is done after every 3 or 4 runs.
Depending on the stability of the running buffer, it is sometimes necessary to
do it before each run. If you want to use the replenishment system, prepare it
as described in “Preparing the Replenishment System if Needed” on page 111.
NOTE
Using parallel replenishment, you can decrease the total time needed for your analysis, as
replenishment and preconditioning are done at the same time. When using this feature, you
have to make sure that vials used in conditioning are not replenished at the same time,
otherwise you will have a vial conflict.
100 Agilent 7100 Capillary Electrophoresis System User Manual