Chromatography Forum

Hi, can someone please explain the purpose of purging PDA detectors - is it to flush out any residual contaminants/samples from previous run before starting a new run?

As far as I know, the detector should be purged for max. 30 minutes before autozeroing it before purging again.

Thank you.

Do you mean as part of a start-up procedure? I use a PDA detector all the time and at the end of my run I flush 90:10 Water:Organic through the system to remove buffer, then 100% Organic for 2 hours before shutting off. Then at the start of the system I light up the lamp for at least 30 minutes before activating run and equilibrate the system with the starting conditions of my mobile phase.

When I get stray peaks or a noisy baseline and I can eliminate the check valves, contamination in my mobile, diluent or standards, then I perform an acid wash of 30% Phosphoric Acid on the entire system and that cleans off any residual drug or rubbish in the flow cell and surrounding connections.

Perhaps you are confused and writing about the wrong type of detector. We do not purge PDA's. We do purge RID (Refractive Index Detector).

Do you mean as part of a start-up procedure? I use a PDA detector all the time and at the end of my run I flush 90:10 Water:Organic through the system to remove buffer, then 100% Organic for 2 hours before shutting off. Then at the start of the system I light up the lamp for at least 30 minutes before activating run and equilibrate the system with the starting conditions of my mobile phase.

When I get stray peaks or a noisy baseline and I can eliminate the check valves, contamination in my mobile, diluent or standards, then I perform an acid wash of 30% Phosphoric Acid on the entire system and that cleans off any residual drug or rubbish in the flow cell and surrounding connections.

30%.. I think it should be 17,5%.can u explain to me? tks

Please do not wash down the system with acid. What does this have to do with "purging" ?? I think you need to speak with someone at your company who is experienced in chromatography.