When i was back flashing the colomn, i forgot to disconnect the dectector. Now the detector cell inlet tube seem to be blocked. Now I connect the pump directly to the detector cell inlet tube,
even under very low flow rate 0.2ml/min, the pressure goes up until to the max limit and pump stops, while i can see some mobile phase come out.
I have cleaned the lens/gasket in an ultrasonic bath, but it didn't help.

Any suggestion?

Thanks!

If the inlet tube is not replaceable, looks like you will probably need to get a new flow cell assembly. Since you probably need a new one, you might as well try a few things. First I would try cutting a short piece off of the end of the inlet tubing, hopefully the blockage is in the end of the tube. You may also try to flow through the flow cell backward. Put a low pressure shutoff on the pump when this is done. If this is an RI, don't do this. Uv cells typically are capable of withstanding up to 1000psi. Ri only about 40psi. If you can disconnect the inlet tubing from the inside of the flow cell and then flow backward, that would be ideal. Good Luck.

Pete

I had a plugged DAD inlet tube on an Agilent 1100, and needed to replace the inlet tube.

Pump warm water ( ~40 C)thru the cell from the outlet side. If there's any chance, this will do it. Otherwise, get out your checkbook...

It works now.
Thank you all.

Have you tried pumping without the detector connected, maybe its just behind the injector.

Otherwise, you can try to cut of 2" from the tubing and hope this helps.

Backflushing the detector is the last option.

Yes. That's how i locate the blocked place.

You can try backflushing HNO3 5%, in water , pH about 1, will dissolve salts and silica, and after, i´d flush in the same direction isopropilic alcohol, and at the end, water to clean. I´ve proved and it made me resolve my problem.