Chromatography Forum

I have question, recently after changing tension cords (both of them), and defining new object positions of each part (x,y,z,), the injection doesn't work properly. It finds its place in the injector port, gives sounds (very strange sound btw) but doesnt inject since the needle doesnt move down. Position and depth at injector port was corrected, everything during the trial seemed to be OK, syringe lowered downd, needle also, but still while running same situation occur, strange sound and nothong, moves back for rinsing. Before changing tension AS was working ok (due to vial problem, we decided to change tension cords), I am afraid that colleague who change the tension might have did something incorrect. Syringe adapter is to me a bit skewed, i see a bit of an angle and have no clue why would change, it is on magnets...
Tomorrow i am going to reopen everything, a bit of a challenge, but maybe one of you have some advice? Thanks in advance

Hello

It is not that simple as it looks.
I'd recommend to get service manual or ask someone who knows how to do it...
The replacement procedure is not very complicated but there are some critical steps that can cause trouble (you need to check tension cords knots - if there is no blockage, you need to measure distance for Mechanical Stop that holds the Needle Guide Assy in position with the defined needle length. Standard setting: 50.5 +0+0.5 mm...etc)

Regards

Tomasz Kubowicz

You say that you have the injector port position and the needle depth set correctly, that the syringe and needle move down, but that the needle does not move down ?? The needle is part of the syringe, so if the syringe moves the needle must move.

What about the plunger of the syringe - the part that slides up and down inside the syringe body to pick up and push out sample - is that the part that is not moving ? If so, reomve the syringe from the holder, and try to move the plunger by hand. If it is difficult to move you need to try to clean the syringe with different solvents.

Peter

Hallo
@ Tomasz, Dzieki, I am aware of this, i did that last time 2 years ago, not an expert, forgot already a lot but remember that it wasnt too complicated after all, definitely not for someone with small hands...anyway, I am not sure what you mean with Needle Guide Assy, i dont do there much... I only remove syringe and some screws from the syringe adapter with torx, I am more thinking if it wasn't installed maybe too close to an electronic card?...

@Peter
Injector port=ok, needle depth 42mm (max 45mm)=ok. during the check performance needle moved down with the proper depth. plunger works okay, because flushing steps (wash station), and at the tray with sample show that plunger works correctly as well. when syringe is on about injecting the sample into GC, moves into injection port and then all of a sudden is blocked, even though position and settings allows for needle to move down and inject..

Hi Dominika

Thanks for clarifying. Are you using the control pad, or software to run the autosampler ? If software, will it inject using the control pad ?

Check for any settings telling it to wait for GC ready or similar conditions.

Peter

Peter, I use software, but indeed i can check if injection would work through the control pad, definitely worth to try, thanks!

I did Peter, and there was same situation. However, i managed to fix it, i removed tension cords, checked all, put them back, changed the magnetic plate holding the syringe and lowered the injection speed (probably one of the student a bit speed up in a time when short cord was not good anymore) and it works good since then Thank you all for suggestions!

Hi Dominika

Thanks for the feedback. What were the injection speeds that did and did not work ?

Peter