Diagnostic Tests; Retention Time Stability Monitoring; Performing The Ramp-And-Decay Test - Waters 515 HPLC Operator's Manual

Diagnostic tests

Regular diagnostic tests can help you to track system performance and
prevent or identify potential problems before they interfere with operation.
Common tests include:
• Retention time stability tests
• Ramp-and-decay test

Retention time stability monitoring

Observing retention time stability during system suitability 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 about retention time stability.

Performing the ramp-and-decay test

Use the ramp-and-decay test to monitor check valve performance. Ensure that
the pump is in the Local mode for this test.
Required materials
• Compression plugs (2) and a tissue
• 5/16-inch open-end wrench (Startup Kit)
• HPLC-grade methanol
Procedure
1. Disconnect the pump outlet tubing from the injector or column and place
the end of the pump outlet tubing in a waste container.
2. Purge the pump with 100% methanol. Use an intermediate eluent to
purge if your eluent is not miscible with methanol. If necessary, see
"Purging the system" on page 3-17.
Diagnostic tests 4-3