Chromatography Forum

Hi

I am having some problems with the autosampler Dionex AS-DV.
When the needle goes down to take some sample, there is a moaning noise that prevents sampling and in most cases, there is a message "needle is jammed" and the status would be "interrupted."
When this happens, there are some other following issues:
1-sometimes the sample below the cap, passes through the cap and moves upwards (a crack in cap is observed)
2-the white filter in the caps is detached and floats in the sample.

I appreciate if anyone can help me with this issue.

Check if needle itself and the whole sample line from needle, through tubing, valve, loop and finally last tubing to waste aren't clogged. Force water flow in counter current from waste tubing to needle. It sholdn't be clogged.

That happens a lot. Your line is probably clogged. It's easy to replace. I keep several on hand in case this occurs. It's Thermo Scientific Sample Tip Assembly part # 040836.

That happens a lot. Your line is probably clogged. It's easy to replace. I keep several on hand in case this occurs. It's Thermo Scientific Sample Tip Assembly part # 040836.

Hi, which line? The line that goes from autosampler to the injection valve?
Is there an instruction for how to replace the line?

Hi, which line? The line that goes from autosampler to the injection valve?
Is there an instruction for how to replace the line?

You need to check all tubings and valve itself in load position. Clogging may occur in the very last tubing.

...
Is there an instruction for how to replace the line?

You really should start with RTFM - (FYI page 74 - Replacing the Sampling Tip and Tubing).
Again, clogged line doesn't necessarily mean clogged tip.

Also - I generally recommend using vial caps with pre-split liners and making sure your caps are on the vials TIGHT.

Also - I generally recommend using vial caps with pre-split liners and making sure your caps are on the vials TIGHT.

Hi. You probable meant different type of vials, not PolyVials for Dionex AS-DV autosampler:

Yep - that's not what I thought you were dealing with.
I get your sample volumes are not typical but wow. One look at those and I think of so many things that could go wrong...

Those are the vials I use. Sometimes you get a bad filter cap that won't let liquid though. When it does the water will end up on top of the vial. I wrote into the procedure to visually check the tops of the vials for liquid to make sure that didn't happen. It used to happen a few times a year but I have not seen one do that in over a year now. The only problem I am seeing now is when you put QC solution in them and get multiple injections from one vial sometimes the second injection is off by 20%. If I replace the cap the injection is fine.

About once a year I get a clogged assembly tip - the line fro the auto sampler to the injection valve. I've never had any other line get clogged so when I hear the grinding noise I just replace the line.The manual is here and the instructions start on pg 69.

https://assets.thermofisher.com/TFS-Ass ... 259-en.pdf

Environmental express makes one with a stainless steel tip. I asked a guy from Thermo if those were any good and he had no idea that anyone made them. I've never tried one.

Those are the vials I use. Sometimes you get a bad filter cap that won't let liquid though. When it does the water will end up on top of the vial. I wrote into the procedure to visually check the tops of the vials for liquid to make sure that didn't happen. It used to happen a few times a year but I have not seen one do that in over a year now. The only problem I am seeing now is when you put QC solution in them and get multiple injections from one vial sometimes the second injection is off by 20%. If I replace the cap the injection is fine.

About once a year I get a clogged assembly tip - the line fro the auto sampler to the injection valve. I've never had any other line get clogged so when I hear the grinding noise I just replace the line.The manual is here and the instructions start on pg 69.

https://assets.thermofisher.com/TFS-Ass ... 259-en.pdf

Environmental express makes one with a stainless steel tip. I asked a guy from Thermo if those were any good and he had no idea that anyone made them. I've never tried one.

Hello

Thank you for your detailed reply and guidance. I just ordered the the assay tip (part number:071575) from ThermoFisher. I hope that all fix the issue.
Is it the same part number that you order for the line?

Thanks

(P/N 071575) is the AS-DV Sampling Tip Kit. That should have what you need. I get 040836 which is just the line since I have the tools I and don;t need the kit. It's best to have extra lines on hand because they can get blocked without warning. That's a big problem when you have time sensitive samples.