Chromatography Forum

Hi,
I am currently having an issue with a ALS (Agilent 7683 Automatic Liquid Sampler, using a 10µL syringe) and a PTV ( Gerstel CIS 4).
Every time the ALS injects in to the PTV it gets stuck and I have to open the ALS door for it to reset.

I have changed every consumable part( liner, ferrules, syringe, etc.) I have trimmed and re fitted the column I have aligned the ALS several times.

I have made sure the ptv is level, but still it jams.

The GC has two inlets a PTV and a S/SL.
When I transferred the ALS over to the S/SL it injected ok with no issues.

Can anyone recommend a way to resolve this?

Thanks

Have you done any maintenance on the Gerstel PTV?
We had several of the CIS-4 PTVs in the lab and it was worthwhile to have a spare head for fast swaps.

Hi Steve, thanks for the reply.
the only thing I have changed is the PTFE Ferrule.

I only have one unfortunately.

Thanks,
Chemiger

Hi Steve, thanks for the reply.
the only thing I have changed is the PTFE Ferrule.

I only have one unfortunately.

Thanks,
Chemiger

Do you have the septumless head on it?

If so, have you disassembled the spring and plunger that seals it and cleaned those? If they get buildup on them they may not slide freely enough and grip the needle too tightly.

Hi,
I haven't opened the septumless head for a few weeks.
I will give this a go.

Thanks,
Chemiger

Make sure that it all moves smoothly check for scoring.
And don't let the spring jump out and hide.

Still having the issue.
could it be the needle type I am using ?

the 10 microlitre syringe is tapered whilst I used a 5 microlitre one before.
that was not tapered.

I have ordered a 5 microlitre syringe to see if I can use the PTV with this.


fingers crossed it works

I really need it to.

Have you checked the needle gauge?

yes checked that thanks.

Still having the issue.
could it be the needle type I am using ?

the 10 microlitre syringe is tapered whilst I used a 5 microlitre one before.
that was not tapered.

I have ordered a 5 microlitre syringe to see if I can use the PTV with this.


fingers crossed it works

I really need it to.

It didn't work the PTv still jammed with the 5 microlitre syringe

Still having the issue.
could it be the needle type I am using ?

the 10 microlitre syringe is tapered whilst I used a 5 microlitre one before.
that was not tapered.

I have ordered a 5 microlitre syringe to see if I can use the PTV with this.


fingers crossed it works

I really need it to.

It didn't work the PTv still jammed with the 5 microlitre syringe

Have you tried a manual injection to see if you can tell how deep it goes before there is resistance?

There might be some type of buildup just inside that is pinching the needle just enough to make it jam. If it is stopping near when it contacts the plunger that seals the inlet, it could be there has been a rough spot develop on the plunger and it needs to be replaced.

I had this issue years ago. Turns out our dual tapered syringe was to blame. As mentioned, perform a manual injection to ensure you can insert the syringe all the way.

What kind of inlet liner do you have ?, and is it possible that the needle is jamming on a baffle or constriction in the liner ?

Peter

It’s been a while but thought I would update.
It was the needle type after all.
Had to get an engineer in to confirm.
Ordered A PTV non tapered needle no jamming.