Contaminant in seal pack causes unexpected peak after system wash on an Alliance - WKB88697

SYMPTOMS

• Contaminant peak shows up in chromatography after formic acid wash
• New solvent bottles, mobile phase, and column tried, but contaminant peak remains
• Same method run on another system with same mobile phase and column did not produce an unexpected peak
• 0-µL injections show peak 
• Methanol injections show peak
• Acetonitrile injections show peak
• PM was done less then one month ago
• Needle wash pump works properly
• Clean Elga water (filtered down to 2 microns)
• Needle wash filter is a dull yellow from customer's previous run on system

ENVIRONMENT

• Alliance HPLC System

• 2695 Separations Module

CAUSE

Needle wash filter, seal pack, and needle are all possibly contaminated.

FIX or WORKAROUND

1. Replace the needle wash filter (700001318).
2. Rebuild the seal pack and replace the needle if necessary. (Part number for seal pack rebuild with needle: WAT271019)
3. Performed adjust seals calibration.

ADDITIONAL INFORMATION