RID stabilization

I am having trouble in stabilizing my RID detector. Please provide me proper procedure for stabilization and getting good baseline in RID. Also when i am joining the column or removing the column there is no effect on the RID baseline.

Parents
  • And as a reminder:

    - never ever operate an RID without a proper degasser. All Agilent degassers can be used with the exception of G1379A and G1379B.

    - always have a TCC/MCT in your stack

    - always have to heater in the optical unit turned on. We recommend to set a temperature of 10 degrees above ambient. The higher, the better, but check for the maximum temperature your column can stand

    - Optical unit temperature and temperature set on the TCC/MCT should be identical

     

    I'm not a big fan of building a hood over the detector. In some situations it might be of help, but often the problem lies with either the environmental conditions or an incorrect setup.

     

    BTW: You can trust my answers, I'm the responsible Product Support Engineer for VWD, MWD, DAD, FLD and RID. What I tell here, is exactly what I teach in my trainings.

Reply
  • And as a reminder:

    - never ever operate an RID without a proper degasser. All Agilent degassers can be used with the exception of G1379A and G1379B.

    - always have a TCC/MCT in your stack

    - always have to heater in the optical unit turned on. We recommend to set a temperature of 10 degrees above ambient. The higher, the better, but check for the maximum temperature your column can stand

    - Optical unit temperature and temperature set on the TCC/MCT should be identical

     

    I'm not a big fan of building a hood over the detector. In some situations it might be of help, but often the problem lies with either the environmental conditions or an incorrect setup.

     

    BTW: You can trust my answers, I'm the responsible Product Support Engineer for VWD, MWD, DAD, FLD and RID. What I tell here, is exactly what I teach in my trainings.

Children
  • I definitely agree that you are the expert here--please don't feel that I am trying to contradict, I know you're speaking the truth.

    My recommendation for using a large solvent reservoir to get good thermal stability is specific to trying to get the absolute best baseline possible, the OQ test limits for the RID are extremely tight and so IMO to get the best results in my experience if you use a large solvent reservoir and set the method conditions flow/temperatures the night before and let it stabilize overnight the results are absolutely beautiful. Of course this comes with the consequence that you need to be really vigilant and meticulous about maintaining your solvents to avoid any situations where excess water is left to develop algae.

     

    Degassing the solvent and having a TCC that is clean (dust free!!!!) are for sure the most important steps. If the solvent quality is poor or the TCC is allowed to get dusty then the performance will suffer for sure.

  • Agreed.

     

    I would never attempt an OQ unless the system was stabilizing overnight. The next morning you just press "Run" on the test and you don't touch or switch anything. This is how we do it in my trainings. However, fixing the environmental conditions (and, of course, have the correct setup) seems the better approach to me, although it's sometimes hard to achieve.

  • Why is a G1379A Agilent degasser not compatible with an RID? The RID I'm using is a G7162A.

  • G1379A and G1379B will work with any Agilent RID (G1362A, G7162A, G7162B), but we don't recommend using them with RID, as their evacuation mode differs from the other degassers and that can be seen on the baseline, which gets more noisy. Depending on your method/peaks, this might be acceptable or not (if you just look for huge peaks, you will very likely not notice the increase in noise).

  • I have been having trouble with RID noise and cleaning the system, a new column, insulating the HPLC lines, bypassing the MCGV, elevating the waste & recycle lines, and replacing the in and outlet valves has not reduced it in any real capacity.

    Is the noise caused by G1379A constant or only when the unit is running? The noise on my system is constant (see attached, diluent and standard injection). Can I test whether the noise is caused by the degasser by simply turning it off, or do the lines need to be removed from the unit?

    Thanks for any help

  • Operating an RID without a degasser connected is not a good idea. You could combine two channels of the degasser to see whether the baseline improves, but like I said before, G1379A/B is not a recommended model.

  • Most important - have a proper setup for the RID, otherwise issues e.g. with the baseline, can be expected:

    - never ever operate an RID without a proper degasser. All Agilent degassers can be used with the exception of G1379A and G1379B

    - always have a TCC/MCT in your stack

    - always have to heater in the optical unit turned on. We recommend to set a temperature of 10 degrees above ambient. The higher, the better, but check for the maximum temperature your column can stand. 55 degrees Celsius is the maximum for the RID

    - optical unit temperature and temperature set on the TCC/MCT should be identical

    - use of an isocratic pump is highly recommended. If a quaternary pump is used, bypass the MCGV, if a binary pump is used, pump A and B 50:50 from ONE bottle

    - have the waste and recycle bottles placed above the RID

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