Chromatography Forum

Hi all,

Just wondering do you know any good way to clean HPLC tubing? This is what I met: Shimazu HPLC, the tubing prior to guard column is blocked(I don't know when and what causes this blockage). I disconnected this part (one end from the auto-sampler, the other end from guard column). Sonicate twice, 2 hrs/time. It doesn't work at all. I cannot push through manually even with a syringe.
Background:
It was run under Aminex HPX-87H in the past 1 year, mobile phase: 0.005M H2SO4, usually analyze fermentation samples;
Currently, I switched to Aminex HPX-87P column to analyze sugars, mobile phase: Nano-water. Around 200 samples are done(they are corn stover hydrolysis samples). The system idled around 2 weeks. Yesterday I started up and found the pressure was too high.

What should I do? To replace a new one, or try some new clean method?
Any suggestions or comment will be appreciated. Have a great weekend!

Lee

I would replace it and not spend time trying to clean it. Unless it is repeatedly happening, in which case you need to determine the cause and provide details such as mobile phase, sample diluent etc.

As already mentioned, replace it if possible. That would be my first option, too.
If you HAVE to clean it, I'd try to connect it in reverse and flush it, starting with a low flow and gradually increasing it as pressure allows. Probably, the plug will plopp out.

That's the BEST option. Usually once you connect it directly to the pump and get the flow started at .5ml ? min., pressure rises to a point where suddenly you will see a major pressure drop. That's it, it's clean. Done this hundredsw of times, really.

For any blocked tubing I'd recommend trying some 50/50 IPA/water, or even 100% IPA and through the high flow rate as suggested above might do the trick?! If your tubing is getting so gunked up might be an idea to check your background pressure as well as you might need to change your pump head frit/filter as well, I have to change mine monthly as using really high salt mobile phases/samples.

lynz x

Given that it only takes about three minutes to cut a new transfer line and swage the ferrules (less with PEEK), my $0.02 worth is that it's easier and cheaper to simply change the line.

Your fermentation products are the main culprit causing the tubing blockage (tubing diameter is very small in order to reduce extra-column volume effect). Actually, company might suggest you to change a bigger diameter tubing in order to reduce tubing blockage but it will affect the selectivity of your peak. You can try to reverse the tubing and flush with 100% water. Start with a high flow rate (5 mL/min) for 10-15 seconds and check the pressure on your system. If the pressure of the system drops gradually, that means the front part of the tubing has clogged. Once the pressure of the system becomes stable, change the flow rate to 1 mL/min and check the pressure again. If the pressure is around 10-12 MPa, it means your tubing is ready to re-use. Some might suggest to use combination of 50/50 of IPA/H20 or MeOH/H2O because this composition has high viscosity and able to push out the clogged particles inside the tubing when you apply high flow rate. It is up to your decision.
If the problem still persists even after you have tried this, replace the tubing with new one. However, remember to fully utilize everything before you decide to throw it away in order to save costs.
Have a nice try.

I think you flushed hot water in participitate channel or back flushing the reverse of the stainlees stell tubing.
one information of you high ph KH2PO4 buffer cause a big problem with higher value of acn. this is the rules for each buffer.