Waters 1500-Series, Operator'S Manual

Page: 111 / 188

Performing pump diagnostic tests 5-3
Performing pump diagnostic tests
The following diagnostic tests can help you track system performance and
prevent or identify potential problems before they interfere with operation:
• Retention time stability test
• Ramp-and-decay test
Retention time stability test
Observing retention time stability during system performance monitoring
tests is useful for determining the performance of your HPLC system and its
components, including the pump. Erratic or changing retention times could be
a result of dirty or malfunctioning check valves, worn plungers or plunger
seals, air bubbles in the lines, incorrectly set flow rate, leaks, or other
pump-related problems. Be aware that other factors, such as system and
column equilibration, column age, operating temperature, and so on, can also
affect retention time stability. See your system suitability documentation for
more information.
Ramp-and-decay test
Use the ramp-and-decay test to monitor check valve performance.
Required materials
• Three compression plugs (part number WAT025566, startup kit)
• Tissues
• Open-end wrench, 5/16-inch (startup kit)
• HPLC-grade methanol
Monitor check valve performance
To perform the ramp-and-decay test:
1. Disconnect the pump outlet tube to the system at the reference valve (or
vent valve for the 1525µ), and install a compression plug in its place.
2. Purge Pump A with 100% methanol (see Chapter 4 ).