Dirty capillary
Capilllary dirty
Radiation damage on a protein can cause its deposition/sticking to capillary internal walls which doesn't go out after a normal sample cell cleaning. The 2D image shows bright homogeneous ring around the beamstop even if filled by water or empty. Sometimes one can also observe problems with loading, flowing a sample in capillary as meniscus is broken/split due to dirty capillary walls. Capillary has to be super-cleaned.
Supercleaning solution consists of 30% Hellmanex (can be found in the yellow container below the table in sample prep lab), 10% of ethanol and rest is H2O. Usually there is some small bottle with it pre-prepared and can be found in the beamline cupboards. Fill a pcr tube with it, put it in sample changer as a normal sample. Set SEU (sample exposure unit) temperature to 40°C. Now you can load about 50 µL of supercleaning solution into capillary and use arrows many times (in/out) in sample changer software (below capillary image) to "wash" it as with a brush.
Never leave some liquid in the capillary without movement when changing SEU temperature! It can (and will) brake!
After about 10 minuts of ''brushing" at 40(50)°C it should be good, set SEU temperature back to room one, or what ever is the working temperature.
You can trash and re-load supercleaning solution several times, don't hesitate to use "normal" clean button.
Figs show as an image of empty however dirty capillary look like and how it looks if clean, respectively.
partners
European Synchrotron Radiation Facility - 71, avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France.