98 1100 Series Nano Pump Service Manual
2 Troubleshooting and Test Functions
Poor peak shape
The peak shape has taken on a fronting or tailing characteristic.
Table 10 Poor peak shape: Possible Causes and Suggested Actions
Possible Causes Suggested Actions Notes
Column performance has
deteriorated
• Try a new column
Poorly made capillary
connections, causing
excessive dead volume or
leaks in a
chromatographically
significant area of the system
• Using a flashlight and absorbent tissue,
carefully check for leaks throughout the system,
especially in the following areas:
a All micro-sampler valve ports.
b Column inlet and outlet.
c Flow cell inlet capillary, at the capillary/cell
body junction.
• Refer to chapter 3 for information on connecting
capillaries. Make sure the capillary connections
are correctly made throughout the system,
especially in the following areas:
a All micro-sampler valve ports.
b Column inlet and outlet.
c Flow cell inlet capillary, at the capillary/cell
body junction.
At very low flow rates, a leak may
never accumulate enough liquid to
trigger the module leak sensors. Low
flow rate leaks are also very hard to
see.
Capillaries which are
internally broken, especially
those capillaries located in a
chromatographically
significant area.
• Refer to chapter 3 for advice on diagnosing an
internally broken capillary. Check capillaries for
an internal break, particularly the needle-seat
capillary, the sampler valve-to-column capillary
and the flow cell inlet capillary.
Capillaries which have been crushed
by module covers are often broken
internally, and may show no external
evidence of a break.