Baseline drifts upward with 2414 Refractive Index Detector - WKB221054

SYMPTOMS

• Baseline drifts upward

ENVIRONMENT

• 515 HPLC Pump
• 2414 Refractive Index Detector
• e2695 Alliance

CAUSE

• Insufficient equilibration between the reference cell and analytical cell
• Temperature
• Contaminated system and column
• Waste tubing plumbing
• Mobile phase

FIX or WORKAROUND

1. Insufficient equilibration between the reference cell and the analytical cell
   → Determine if improvement is possible by using a long purge time (about 30 minutes).

2. Temperature (temperatures of the column heater and the 2414 detector cell)
   → Make the cell temperature as close as possible to the column temperature.

3. Contaminated system and column
   → For column cleaning, refer to the Care & Use Manual for the column.
   See 2695 Separations Module System Cleaning Method-WKB91424 for system cleaning procedures.
   * Remove the solvent filter (the filter attached to the end of the line inserted into the solvent bottle) before cleaning the system, sonicate it, and reattach it after system cleaning.
   * During system cleaning, put the RI detector in the purge state to clean the reference cell as well.
   * During system cleaning, switch the valve of the manual injector to clean the valve as well.
   * During system cleaning, you can also monitor the baseline to check the drift condition.
   In that case, it is easy to drift without a column, so if you have a column that will no longer be used, you may want to connect it.

4. Waste tubing plumbing
   → Determine if the waste line from the detector outlet is bent or if it is submerged in the waste in the solvent bottle.

5. Mobile phase
   → Make fresh mobile phase and replace the entire bottle. When using a mix of multiple solvents, insufficient mixing may be the cause.

ADDITIONAL INFORMATION