High backpressure in a 1260 Infinity II System

Hello, 

We have an Agilent 1260 Infinity II system with the following configuration:

Pump: G7111B

ALS: G7129A with ICC (inner capillaries 0.17 mm)

Detector: G7115A

It works with the following method:

Flowrate: 1 mL/min

Mobile phase:

  • 69.5% ACN
  • 30.5% Ammonium formate/Formic acid 0.03M

Compresibility: 80E-6/Bar

ICC Temperature: 30°C

Column: Perkin Elmer Brownlee SPP C18 2.7 um 150 x 3.0 mm

Normally system works with a pressure of 320 Bar, but in past days pressure suddenly rose above 400 Bar, we thought that column was the culprit but we tried with other columns with the same results (even with a new one). So we looked for other sources for the pressure rising but system pressure without column was around 25 Bar using a ZDV when the system was flushed with water at 1 mL/min flowrate. 

Mobile phases are filtered with 0.45 um membranes and standards and samples are filtered with syringe filters of 0.45 um, solvents are HPLC grade.

PM/OQPV was recently performed with successful results.

Thanks for your help.

Parents Reply
  • Hi, I was checking the pressure element by element in the flow path, but I didn´t find anomalies.

    Elements was checked with water at 1 mL/min flowrate and 30°C

    Pressure cumulative (Bar) Pressure (Bar) Element tested
    0.31 0.31 Pump Head + Damper + Purge valve (opened) + Frit 
    0.31 0.00 Pump Head + Damper + Purge valve (closed) + Frit
    6.26 5.95 0.17 mm Capillary connection between Pump - ALS
    6.30 0.04 Rotor seal Groove 1 + Injection valve Pos 1 + Injection Valve Pos 2 + Capillary connection between injection valve - metering device 
    6.34 0.04 Metering Device
    7.19 0.85 Sample loop + needle + needle seat
    7.89 0.70 Injection val Pos 5 + Rotor seal groove 2  + Injection valve Pos 6 + Capillary conection between ALS - ICC 
    10.48 2.59 ICC channel A (0.17 mm Capillary)
    10.46 2.57 ICC channel B (0.17 mm Capillary)
    14.79 4.31 0.17 mm Capillary connection ICC - column
    19.22 4.43 0.17 mm Capillary connection column - flow cell
    24.71 5.49 Flow cell
    102.81 78.10 Restriction Capillary
Children
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