7673 ALS not injecting correct volume

[pacerlaser]

Hello, I've got a 7673 autosampler with my 5890 GC and I noticed that it does not inject the correct amount. I am wondering what part I need to replace to remedy the problem. I am looking at this document: https://www.agilent.com/cs/library/Supp ... a03019.pdf and is it the plunger motor assembly I need to replace? I have tried other syringes and determined that changing the syringe makes no difference. Any help would be greatly appreciated.

[tkubowicz]

Hello

Are you sure that sampler is a problem? First of all I'd recommend to confirm that it is a sampler problem.

1.Make few manual injections - if RSD for 3-5 injections is about 1-2% you can assume that it is not inlet problem (however I'd check inlet for leaks as well)
2.Check if syringe you're using is ok (sometimes new syringes are not tight)
3.Try to inject your standard without any syringe washing (just your std, no washing solvents), 3 sample washing, 6 pumps
4.As I remember there is alignment procedure for 7673 sampler - it is last thing I'd check

Good luck

Regards

Tomasz Kubowicz

[dblux_]

Have you configured correct volume of the syringe ?

Check whether the syringe barrel fills properly with solvent or sample. Shed light from electric torch to the syringe when it draws liquid. You will see if it fills properly and without air bubbles (provided 7673 has translucent door as 7683 ALS).

[pacerlaser]

I basically watch it do the injection. It is set for a 2 uL injection and when the autosampler "clicks" to move the plunger for each 1 uL mark up on the syringe, it clicks twice but only moves the plunger to the 1 uL mark on the syringe.

[dblux_]

Try to clean the magnet and plunger sensor.

[James_Ball]

I basically watch it do the injection. It is set for a 2 uL injection and when the autosampler "clicks" to move the plunger for each 1 uL mark up on the syringe, it clicks twice but only moves the plunger to the 1 uL mark on the syringe.

We have had that problem before and sometimes you have to replace the solenoid that pulls the plunger stop back with each ul step. It can pull up to 1ul (the first step) even if the lever doesn't move, but if it doesn't move it won't pull up any further. Watch to see if the plastic lever that catches on the stops moves out of the way with each click, if not then that solenoid is dirty or bad. If it moves but the plunger doesn't, then it is either the plunger motor or the slides are dirty.

[Bigbear]

Sounds as if the nanoliter enable setting is on. Using a 10ul syringe with the nanoliter setting at 2,is set to deliver 1ul. With this setup, injector stop 3 gives 2ul.
I have the same issue as we use a non Agilent control software. The injector controls refer to volume, but they are injector stops.

[Consumer Products Guy]

Try to clean the magnet and plunger sensor.

Clean off all the stainless steel guide rods - just use methanol on a swab, do not lube either.

[thohry]

Try to clean the magnet and plunger sensor.

Clean off all the stainless steel guide rods - just use methanol on a swab, do not lube either.

I sometimes have problem of reproducibility and never think of the Injector. May be next time I would try your suggestion.

[seet88]

Hi,

Can you check the front/back injector setting? See the volume withdraw is it 1ul? If yes mean the gc method not syn to the method, hence you need to upload the method.

thanks