Agilent Cool on column ALS injector problems

Afternoon forum members,

 

I am hoping that someone might be able to shed some light on our injector issue. We had a COC injector port installed on the back inlet of our 7890a GC - FID.

 

When the autosampler (7963 plugged into back inlet port) lowers to inject the sample - the A/S stops with a shudder and goes into fault mode - the plunger remains depressed. I can manually inject the sample at this point and then raise the injector. Needle is not bent. I have loosened off the septa cap to ensure the needle is not getting pinched during the injection, and double checked that the syringe needle was not the problem by removing it altogether and trying another injection - ALS stops at point of injection.

 

Fault log reports 'Sampler error #901 Auto Injector back tower syringe error' and turret flashes red twice, which according to the manual indicates that I need to reinstate or replace syringe - both of which I have done

 

I have tried realigning the A/S using the automatic align on the turret - and all seems OK. I can manually inject a sample, so I am happy with the alignment of the 0.53um guard column and associated COC parts and we have the 0.53 on column nut with septa in place. I have also changed the needle guide 'foot' to the one that came with the kit.

 

The needle is a 5ul Agilent on column syringe (5182 0836) with 0.32 needle, inlet pressure is 10psi has a septum purge of 15ml/min.

 

Has anyone experienced this issue - or be able to shed some light on it please.

 

Many thanks,

 

Matt

  • Hi Matt,

     

    The cool on column inlet does sit lower and the ALS should be accommodating for the height difference.  From everything that you've told me it sounds like the syringe carriage is encountering an interference and we need to determine what the interference is.

     

    Can you try the following:

    1.  Use the same needle guide "foot" that you are using for the SSL inlet.  This is the needle guide "foot" that should be used with a .53mm column.  Try to run the ALS and see if it works.

    2.  If step 1 doesn't work, take out the syringe and entire needle guide assembly (the part that the needle guide "foot" is connected to) and try to run the ALS.

     

    Let me know the results of step 1 and 2.  If the ALS errors in both of these cases, can you please take a video recording (without the needle guide assembly installed) so that I can see at what point the ALS is having trouble?  If the video file is too large to upload, you can send me an email @ kristen.sensabaugh@agilent.com.

     

    Thanks,

    Kristen

  • Hi Matt:

     

    I am entering the forum late, so hopefully by now you have resolved your problem.  I also use COC injection, but with Mass Spec.  Initially I had some problems with the COC injector in which the 5uL needles were bending on injection; however, this was coupled with other problems that were more related to the mass spec and the new extractor source.  Initially we did not use a guard column, but the service engineer added the 0.53 um guard column and also switched the needle to a 10ul fixed needle (part# 5181-1267).  This alleviated the bent needle.  I don't know if that will help your situation since you didn't seem to have a problem with your needle.  Also make sure in your Inlet & Injection Parameters, the inlet location is set for Rear and the injection source is set for GC-ALS and not manual.  Also that the ALS is set for back injector.  Again, hopefully you have resolved your problem and are up and running.

     

    Regards,

    Dawn Harrison

    USDA

  • Hi Kristen,

     

    Sorry I didn't get back to you. No, we have not been able to get any

    further forward and I was away last week. I am not going to be able to do

    anymore of that until next week - other instruments are misbehaving! I need

    to get a video of it for you 'not injecting', and I will try to do that

    first thing.

     

    Thank you for following up though

     

    Have a great weekend.

     

    Matt

  • Hi Matt,

     

    Were you able to get your ALS injector to work on your Cool on Column inlet?

     

    Thanks,

    Kristen

  • Hi Kristen,

     

    I may have found the solution. The needle guide for the COC injector needed

    modifying by removing 3mm of plastic from the upper cylinder to stop the

    needle barrel hitting it as the carriage came down. It would appear that

    the syringe and foot combination do not quite work in harmony on our ALS. I

    do now have a method that is happily injecting samples automatically.

     

    I did make a short video of the problem which I can upload if you would

    still like me to.

     

    Have a great weekend

     

    Matt

  • Hi Matt,

     

    I apologize for the delayed response; I was out on holiday.  If you can upload the video showing the problem that would be nice.  If you can't upload the file, please email it to me.  Are you now using the same needle guide "foot" that you are using for the SSL inlet?

     

    Have a great weekend!

     

    Best Regards,

    Kristen

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