Low system pressure and shifting retention times on SM-FTN - WKB15653

SYMPTOMS

• Shifting retention times
• Low system pressure (possibly "system under pressure" error if lower pressure limit is configured in the inlet method)
• Needle Seal Readiness Test fails at flow rates resulting in same or higher back pressure as the application method
• Dynamic Leak test fails if run with endpoint column plus needle and seal included 
• System pressure stable and then fluctuates after 20 minutes whilst system is idle (due to injection valve switching from Load to Inject position)

ENVIRONMENT

• ACQUITY UPLC Sample Manager - Flow Through Needle PLUS (SM-FTN PLUS)
• ACQUITY UPLC I-Class Sample Manager - Flow Through Needle
• ACQUITY UPLC H-Class Sample Manager - Flow Through Needle

CAUSE

1. Needle and needle seat are damaged.

2. Needle damages more often when using non preslit vial cap

FIX or WORKAROUND

1. Replace needle and needle seat, Part Number 700005215

ADDITIONAL INFORMATION

Prior to replacement, the characterize needle seal diagnostic may pass, but the needle seal readiness test will fail.

In order to avoid damage at the new material, it is best practice to always change both the needle and the needle seal at the same time.