LC Packings Probot 161403, Руководство пользователя

Страница: 78 / 118

Maintenance and Troubleshooting
3-10
D960R3
User’s Manual Probot
3.4 Troubleshooting
Troubleshooting refers to the determination of the cause of a problem. Since the
Probot Micro Fraction Collector is typically incorporated into an HPLC system,
the first step is to determine if the problem is due to the collector. The Probot
should be removed from the system and an injection should be performed.
Compare the results from the two runs; if the observed results without the
Probot present acceptable data, the problem is most likely due to the Probot
Micro Fraction Collector.
Analytical problems also might be caused by external influences, like temperature
and/or light sensitive samples. For this reason it is important to be sure the
application was running without problems before and nothing has been changed.
TABLE 3-4 Troubleshooting the Probot Micro Fraction Collector
Problem Probable Cause Solution
Wrong control parameter.
The Z-stepper motor is
missing steps.
Check the maximum speed
and acceleration settings
(Section 2.8.7).
The table drops during a run
or homes itself
unexpectedly.
TTL signals are generated
very shortly after each
other.
Check the timing (Sections
B.6 and D.6).
Wrong control parameter.
The Z-stepper motor is
missing steps.
Check the maximum speed
and acceleration settings
(Section 2.8.7). The distance between
needle and table increases
during a run.
Wrong table alignment.
Check table alignment
(APPENDIX C).
Strange noise from the
stepper motors, table not
moving.
The motor is losing steps.
Check the maximum speed
and acceleration settings
(Section 2.8.7).
Air in the connecting tubing
or in the syringe.
Check the entire flow path
for air bubbles (e.g. syringe,
tubing, etc.).
Probot needle with the
fused silica capillary is too
far above the target.
Adjust the table height
(e.g. the fused silica
capillary should touch the
target during sample
deposition when nano flows
are applied).
Fused silica capillary not
properly installed.
Visible part of the fused
silica capillary should extend
the needle by 0.5 – 1 mm.
Fused silica capillary/needle
is damaged.
Replace capillary/needle.
Different volume of droplets
or no droplets on the target
(e.g. the following pattern is
obtained):
Wrong OK
Wrong table alignment.
Check table alignment
(APPENDIX C).
The first droplets are
different (e.g. too small). Crystallization of the matrix
solution on the needle tip.
Perform a wash and/or a
dispense step prior
fractionation.