column collapsed, please help

[Rganga]

I am using a Thermo high purity c 18 column (150*4.6 and 5u pore size) to analyse eicosanoids. I am a new HPLC user and just starting with this new method.
After 1 month of leaving the machine off (holidays), the first day to start working, there was no flow? Trying to understand what happened, I moved out all the column ends (precolumn..) and I found that there is no flow out from the column. The column is collapsed? How I can regenerate it? And How I could avoid this in the future (how to conserve it)?
Thank you very much

[Consumer Products Guy]

Is there flow if you disconnect the head end of the column? If so, sounds more like your column is clogged; did your previous mobile phase contain any solids (buffers) dissolved in it, which may have clogged everything once the mobile phase dried? In that case: keep it pumping at slow flow, or rinse with solvents only before shutting down.

[danko]

Hi Rganga

A collapsed column does not obstruct the flow. Also, if the column blocks the flow in anyway, you’ll observe a rapid pressure rise until you stop the flow or the pump stops it for you.

I will put it to you that there is air in your pump/s. If so, just prime your system and potentially give it a helping hand by sucking 5 to 10 mL eluent with a syringe.

Best Regards

[Rganga]

I am using a Thermo high purity c 18 column (150*4.6 and 5u pore size) to analyse eicosanoids. I am a new HPLC user and just starting with this new method.
After 1 month of leaving the machine off (holidays), the first day to start working, there was no flow? Trying to understand what happened, I moved out all the column ends (precolumn..) and I found that there is no flow out from the column. The column is collapsed? How I can regenerate it?
I tried to clean it with a 50% Acetonitril at 0.5ml/min, there is no flow at the end of the column and after 10 min the pression is going up and the machine is stopped when the pression gets the max.
I am so lost, please help me

Thank you very much in advance

[Jackus]

What is your instrument model?

First, find the critical point, which is clogged. Pressurize the system and go from analytical column to pump. Unscrew the capillary on the top of column. When pressure drops, the problem is in your column. When not, check your autosampler. The needle or needle seat may be clogged with piece of septum. Sometimes may be problem in plugged capillary or dirty filter in pump output.

When you finally see that your column is plugged, try to flush it with approx. 0,2 ml/min or lower in "reverse order" but disconect it from detector input capillary first.

[Rganga]

Thank you very much for your assistance,
I found that the problem was in the precolumn, which is colapsed.
Thank you