UPC2 system high-pressure shutdown when performing gradient with high % co-solvent - WKB15645

Article number: 15645

SYMPTOMS

High pressure and shutdown when using second 30cm Single Zone Column Manager (CM-30S)
Initial conditions of gradient are stable at 95% CO2 (A) and 5% acetonitrile co-solvent (B)
At injection, pressure increases as the gradient approaches 40%A and 60%B
- Overpressure occurs during runtime on the second injection
- All eight columns positions in the secondary CM-30S exhibit this overpressure and system shutdown
Injections made across all columns in the primary CM-30S do not overpressure
- Isocratic method results in good performance across all seven column positions in the primary CM-30S
Flushing the system overnight, high-pressure shutdowns during injections; re-traced flow paths and checked for blockages
- ABPR health check and diagnostic pass
- CM-30S inlet and outlet tubing new
- Inject, auxiliary, and column switching valve cartridges new
- 2998 flow cell new
System with fresh solvents used for UPC2 startup testing using a union (no column) and methanol and CO2—pressure and system were fine
System with the chemists solvent (ACN + 0.2% isopropylamine) and up to 65% co-solvent—the system went over pressure and shut down
- Major spikes observed toward the higher composition of co-solvent

Pressure spikes observed higher composition co-solvent.png

Co-solvent, mobile phase contamination from topping off solvents

Co-solvent glass bottle dated November 2015
Suspect water content in mobile phase contributed to high pressure; composition of co-solvent increased above 50%

Perform a 100% acetonitrile co-solvent flush through the entire UPC2 system:

Connect each module one at a time in order to wash off any contamination or poor quality solvent from the system components
Flush each module (approximately one hour) and monitor pressure because high pressure could still occur

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