Chromatography Forum

Hello Guys,

The injector for Agilent 1100 doesnt seem to move even when I am trying to reset it. It is a auto injector and I am not sure how to make it work again. Any help would be very useful.

In anticipation

The ato sampler has been rectified but has led to a new problem. As soon as I inject the sample the pressure is rising rapidly, there appears to be a block from the injector to the column flow in the solvent. Can anybody suggest some possible rectifications tothis problem.


Would be highly obliging.

I've had this happen before; wear particles from the autosampler rotor seal can clog up stuff in there. Open up the autosampler rotor valve and clean out all particles with swab/solvent, and install new rotor seal.

http://www.chem.agilent.com/en-US/Suppo ... 01733.aspx

http://www.chem.agilent.com/en-US/Suppo ... 01260.aspx

http://www.chem.agilent.com/Library/Sup ... A03695.pdf

http://www.chem.agilent.com/Library/use ... _ebook.pdf

Thanks a lot to both of you,

I hope the suggestions work out

Hi Guys,


My problem with the injector is still continuing, in detail.

The valve has been replaced after washing. So the rotor valve appears to be OK.
There was a deposition of buffer in the Injection seat, and till the needle is sitting in the seat the pressure rises even if the valve to the column is open, while as soon as I move the needle to needle home the problem is sorted out and there is no pressure problem.

Could anyone suggest me what can be done with the auto sampler for this Agilent 1100 device. Could it be due to clogged needle or impurity.

Awaiting for your suggestions deperately

I'm puzzled. With the design of this injector, the needle sits in the seat permanently while there's flow; it only comes out to collect sample. Could you explain what you mean by the problem going away when the needle is "home"?

If you've got deposit in the needle seat it could imply an unacceptable level of leak at the seat? Do check the trivial thing, that you aren't using very dirty vials! Because the vial is carried to the needle seat and put on top of it while the needle goes down, there is a nice possibility for transfer of dirt from the bottom of a vial rack to the bottom of a vial, to the needle seat...

Also it might be worth checking that your samples are in a solvent compatible with the mobile phase, and are themselves free of any precipitate. If you take a sample in pure organic phase, for example, and inject using a needle full of phosphate buffer, there is an outside chance you will precipitate buffer on injection.

Personally, I am a big fan of checking the needle and needle seat are not clogged before dismantling the valve. Checking they're clean is merely a matter of taking the relevant tube off the valve while the needle is moved upwards, and squirting some water through it to make sure it runs freely. It's so easy to do, I'd prefer to check this before going for more drastic options.

I presume You already tryied to disconnect column and wash the flow path with water to dissolve buffer crystals.

Move needle into "change needle" position from service menu. Then using magnifying glass check if needle is not partially clogged. Sometimes there are parts of septa/cap blocking flow or some sediment from the sample.

Next step would be to check sadle, but it is quite complicated to see inside. Beter would be to dismantle and wash. In the beginning just connecting "reverse flow" - to blow out possible contamination. Additionaly could be immersed in water/methanol and washed in ultrasonic bath.

If this does not help more complicated/expensive would be try to change needle, sadle, if does not help - capillary to the needle and see which of them is faulty.

Call for service from Agilent!
It may be caused by the motor damage. We should often clean the auto sampler to keep it from dust.