2424 ELSD high baseline noise - WKB9318

SYMPTOMS

• High baseline noise 

ENVIRONMENT

• 2424 Evaporative Light Scattering Detector

CAUSE

Pollution of drift tube

FIX or WORKAROUND

1. Replace the column with a union.
2. Set drift tube temperature to 100 degrees C, nebulizer heater level to 75%, and gas pressure to 50 psi.
3. Flush the system with water for 60 minutes and set the flow to 1 mL/min.
4. Set drift temperature to 50 degrees C, nebulizer to 30%, and gas to 50 psi.
5. Flush the system with acetone or acetonitrile for 30 minutes and set the flow to 1 mL/min.
6. Flush the system with methanol for 30 minutes and set the flow to 1 mL/min.
7. To clean the drift tube, stop the solvent flow and keep the gas pressure, drift tube temperature, and nebulizer heater level for at least two hours.

ADDITIONAL INFORMATION

The procedure given above is more thorough than the normal water-only procedure described in the 2424 Evaporative Light Scattering Detector Overview and Maintenance Guide (715004755) (Chapter 4.6 in Rev. A).