Thermo Scientific VC-D60 Operating Manual page 113

Symptom
Drift
Baseline drift
occurs in few
hours of start
Baseline will not
zero
Intensity alarm
Refractive Index Detector (VC-D60)
Operating Manual
Possible Cause Remedial Action
Flow cell dirty Clean the reference and sample cells. See
Cell
Flow cell damaged Check for liquid in drain tubing indicating a broken flow cell.
Contact Technical Support.
Contamination from Flush the HPLC system with a solvent stronger than the mobile
HPLC System phase (less polar for reversed phase) until the contaminant
disappears.
Contaminated or non- Prepare fresh mobile phase (premixed, degassed).
HPLC-grade solvents
Vapor pressure of •
mobile phase is too
high for operating
•
temperature, causing
air bubble formation in
the reference cell
Tetrahydrofuran (THF) •
in the mobile phase
oxidizes in reference
•
cell
Reference cell solvent Flush reference cell with mobile phase (see
has aged and Cell
deteriorated
Sample and reference Flush sample and reference cells with mobile phase (see
cells do not contain Purging the Flow Cell
identical solutions
Reference cell contains Flush sample and reference cells with mobile phase (see
air bubbles Purging the Flow Cell
Flow cell dirty Clean the reference and sample cells. See
Cell
Flow cell damaged Check for liquid in drain tubing indicating a broken flow cell.
Contact Technical Support.
Lamp deteriorated or Check the value for the ValidationLampVoltage. If it exceeds
out of adjustment 4.5 V, contact Technical Support.
Flow cell dirty Clean the reference and sample cells. See
Cell
Lamp burned out Contact Technical Support.
Flow cell empty Fill the flow cell with eluent.
(} page 90).
Turn temperature control off, or reduce the nominal
temperature.
Modify your method to exclude or decrease the
concentration of troublesome solvent.
Add an antioxidant to stabilize the THF, if compatible with
other chromatographic requirements.
Allow >2 hours stabilization time for oxidation in reference
cell to reach a steady state condition.
(} page 78)).
(} page 78)).
(} page 78)).
(} page 90).
(} page 90).
8 • Troubleshooting
Cleaning the Flow
Purging the Flow
Cleaning the Flow
Cleaning the Flow
Page 113