Bio-Rad PROTEAN® IEF Cell Accessories User Manual

Page 41

10.2.3. IPG Strip Storage

IPG strips can be stored indefinitely at -80 °C after the run. A rehydration tray and lid
can be used to store the IPG strips.

10.2.4. IPG Strip Equilibration (prior to 2

dimension)

To equilibrate IPG strips, fill each channel with DTT Equilibration buffer and soak for 10
minutes. Discard the solution and add the iodoacetamide equilibration solution and soak
for an additional 10 minutes. Then place the IPG Strip on the second dimension gel.

Section 11
Troubleshooting

If a system or operator error occurs the appropriate error message will appear on the LCD

display. The power is not applied to the system/electrodes when an error message is displayed.

Problem

Cause

Solution

Initial low or zero

• Poor contact between IPG

• Check contact between IPG

current

strips and electrode.

strips and electrode. Make
sure the focusing tray lid is
placed correctly.

• Incomplete contact between

• Check placement of focusing

tray electrodes and PROTEAN tray to insure proper contact
IEF Cell connections.

between tray electrodes and
PROTEAN IEF Cell connec-
tions.

• Incomplete IPG strip

• Make sure that the IPG strips

rehydration

are completely and evenly re-
hydrated. Check rehydration
volumes and rehydration times.

Voltage is not

• Salt concentration too high

• Check salt concentration

increasing during

and/or desalt sample.

voltage ramping steps.

Voltage does not

• Bio-Lyte concentration too

• Reduce Bio-Lyte concentration

reach programmed

high

to 0.2% (v/v).

value, or maximum

• Set voltage too high for IPG

• Program volt-hours for

voltage is reached

strip size and pH gradient.

focusing step to insure

very slowly

complete focusing of sample.

• Excess sample during re-

• If greater than recommended

hydration did not enter gel,

sample volumes are used make

or IPG gels overswelled

sure all off sample has entered

with excess sample

gel, or remove excess sample
prior to focusing.

Large fluctuations in

• IPG strips contain poorly

• Check rehydration volume

Voltage and current.

rehydrated regions, or

and time. Make sure rehy-

(also resistance error

IPG strips have dried out

dration solution is evenly

message displayed)

during the run.

distributed during rehydration.

• Current limit too high.

• We recommend a current limit

of 50 µA/strip. Make sure the
correct number of IPG strips
was entered.