Cleaning Recommendations for Agilent ELSDs

This Information Applies To: Agilent ELSDs G4260A, G4260B, G4261A, G4621B, G7102A, G7102B

Content:

If the evaporator tube of ELSD becomes contaminated with non-volatile material resulting in poor chromatography, please use the steps below to troubleshoot and clean the ELSD.

Steps to Follow:

It is recommended that the instrument is initially washed with a solvent suitable for contamination. 

Caution: Do not use solvents that contain additives when performing the cleaning procedure.

Caution: Please read all relevant MSDS for the solvents being used, and follow all safety guidance including storage, handling, ventilation and extraction requirements, and the use of appropriate PPE.

One of the “cleaning” solvents recommended is Acetone/Water (50/50) (based on your application, select the appropriate solvent to clean the contamination).

Cleaning Procedure: 

1. Set Evaporator temperature to 40 ℃.
2. Set the Nebulizer temperature to 40 ℃.
3. Set gas flow to 2.5 SLM.
4. Connect the ELSD directly to the HPLC pump (bypassing the ALS and column).
5. Pump the “cleaning” solvent into the instrument at 1 or 2 mL/min (while in the RUN mode).
6. Perform this procedure overnight or for a minimum of 4 hours. Make sure that there is the required volume of cleaning solvent for the flushing time. 
7. During the cleaning procedure, the ELSD response may show a full-scale deflection. This indicates that contamination is being flushed from the detector.
8. Following the cleaning procedure, reconnect the column and ALS and inject a sample of known response.
9. Repeat the wash procedure with a different solvent, or for a longer period if the ELSD signal is not improved.

Preventative Maintenance:

Depending on use, it is recommended to clean the evaporator tube at least once a week or every 40 hours.

The build-up of contamination can be identified early by monitoring the baseline noise over time, or by checking the ELSD offset reading.

To check the ELSD offset value;

1. Switch off the ELSD.
2. Switch the detector back on and place it into RUN mode.
3. Record the ELSD reading from the front panel -this is the OFFSET value
4. Offset values above 140 mV indicate contamination and it is recommended the ELSD be cleaned.

It is also recommended to clean the unit following the use of buffers, or where the sample matrix contains impurities (i.e. "dirty" sample).

If cleaning the unit does not cure the problems then contact Agilent Technologies for further assistance.

Learn how to effectively maintain Agilent ELSD: See the ELSD User Manual on Agilent.com.