Chromatography Forum

Hi!

Sorry for my English first of all.
I have Waters Alliance HPLC system with 2414 Refractive Index Detector. According to manual maximum pressure for the flow cell is 690kPa (6.9 bar, 100 psi). But flow 0.5 ml/min (water) through the detector without a column gives pressure greater 100 psi. For Purge Mode pressure in two times greater than for Normal Mode (checked for 0.2 – 0.3 ml/min).
Any comments who used 2414 Refractive Index Detector.

Or you have a flow restrictor installed after the detector or you have a blockage inside it.
Resolve it or you will break the cells.

Or you have a flow restrictor installed after the detector or you have a blockage inside it.
Resolve it or you will break the cells.

Change the detector construction do you mean? It is WATERS, its devices are complete.

Or you have a flow restrictor installed after the detector or you have a blockage inside it.
Resolve it or you will break the cells.

Change the detector construction do you mean? It is WATERS, its devices are complete.

It sounds like you have a clog somewhere...

First have you disconnected the detector and checked the pressure to make sure sure that part of the problem is not upstream? Try that first.

If that is not the issue, disconnect the detector outlet... If the pressure drops just change that line (and.or empty your waste if full - a full waste container can cause a lot of back pressure!).

If not it may be in the cell proper or the tubing leading into or out of the cell itself.

If you are using salts in your mobile phase they may have precipitated in the detector or the line afterwards... If so try running water at a low flow rate for a LONG time to try and dissolve the salts.

If not try appropriate solvents at low flow that might dissolve whatever might be in there.

Good luck,
- Karen

Karen, it seems that if filling the waste container increases you backpressure you are doing something wrong, like letting the waste tubing hang into the container.

Karen, it seems that if filling the waste container increases you backpressure you are doing something wrong, like letting the waste tubing hang into the container.

If it's overflowing, the tube is usually in the liquid.

Yes that happened to me ... once back in he 1980's.

- Karen

Thanks Karen, I was really short answering him.

I called to Waters Technical Service. The specialist answered don’t take into consideration the “max. cell pressure” 100 psi. Next day I carried out hplc method using the detector. Pressure was about 500 psi. All substances were successfully eluted and detected.
Thanks.

The outlet tube of the RI detector should have a large diameter (0.040 inch ID) and must not hang in the waste solvent (provide a free fall of the drops).