Agilent Cool on column ALS injector problems

Hi Matt,

Did the system work before, and if it did, did anything change between the time that the system was working and now?

It is important that all of the autosampler and inlet/column components are compatible with one another.  You can verify this one of two ways:

1.  Use the Parts Finder Tool.  If you don't have the Parts Finder Tool, you can download it from Agilent.com here:  Agilent | Parts Finder Tool

If you view the 7890A GC model, click on the inlets view and select cool on column you can see a nice visual representation of the components that need to be installed with a .53mm column.

2.  Reference the Cool on Column section beginning on page 93 in the 7890 Series Maintenance Manual:  http://www.agilent.com/cs/library/usermanuals/public/G3430-90052%207890B_Maintaining%20Guide.pdf

Let me know what you find and we can go from there.

Best Regards,

Kristen

Hi Kristen,

Thanks for the speedy reply and links, really useful.

Everything parts wise appear OK. The ALS syringe (5ul gold syringe barrel (5182 0836) with 0.32um 26-32/42 cone needle (5182-0831)) is listed under 7673/7683 On Column autosampler syringes, but appears in the parts finder under the A/S we are using. I believe that Agilent put the parts list together for us when we requested a quote for the inlet. The installation engineer didn't raise any problems - but as we did not have the ferrules at time of installation - we could not install the column and test the ALS

The system (which was connected to the MS instead of the FID) was working correctly on the split/splitless inlet (albeit with a different syringe) the day before, so I am pretty sure it is all working correctly. I am going to change the inlet in the method and check - it would be sheer coincidence if the A/S has gone wrong at exactly the same time as changing the inlets (but stranger things do happen!)

Not sure if this helps to narrow down the problem?

Thanks

Matt

Hi Matt,

Thank you for the information.  Trying to run the ALS on the Split Splitless Inlet should help to rule out a problem with the ALS; as you said I would be surprised if it errors out (as long as you remember to change the needle support guide and syringe).

You mentioned that you did change the ALS needle support guide to operate on the Cool on Column, which is critical.  Can you reference page 110 in the maintenance manual to verify the correct part is installed in the ALS for use with the cool on column, and also make sure that it is installed properly:  http://www.agilent.com/cs/library/usermanuals/public/G3430-90052%207890B_Maintaining%20Guide.pdf 

I'm guessing that in your method for the cool on column you have the method configured to use the back injector, correct?  Did you change the way the ALS is plugged into the back of the GC?  I don't know if that should really matter or not, but this is worth trying.  Shut down your data system (software control).  Power off the GC, and plug the ALS cable into the middle ALS port (refer to page 13 of the installation manual, I think it is referred to as Sampler 2 or Back Injector on the back of the GC):  http://www.agilent.com/cs/library/usermanuals/public/7890B_Installation.pdf  After you change the cable position, power on the GC and then re-launch the software control.  You will probably get a notice that the GC configuration has changed, which is normal.

A couple of notes about supply choice: thru-hole septa would be recommended (part number 5181-1260), and if you are injecting into a .530 retention gap, using a 23/26 gauge needle is a robust solution.

Let me know what the results of your tests are and we'll go from there.

Best Regards,

Kristen

Hi Kristen,

Checked the ALS on the front inlet S/S and all ok. The support guide is

installed correctly as per the installation guide, and I have had the ALS

plugged into both front and back sampler ports, no improvement in either

case.

Is it possible that the difference in height between the front and back

inlets in relation to where the autosampler mounts has anything to do with

this, the top of the  COC inlet septa nut have screw threads, but for what

is not clear. The S/S stand proud compared with the COC which is much lower?

Thanks again

Matt

Hi Kristen,

Checked the ALS on the front inlet S/S and all ok. The support guide is

installed correctly as per the installation guide, and I have had the ALS

plugged into both front and back sampler ports, no improvement in either

case.

Is it possible that the difference in height between the front and back

inlets in relation to where the autosampler mounts has anything to do with

this, the top of the  COC inlet septa nut have screw threads, but for what

is not clear. The S/S stand proud compared with the COC which is much lower?

Thanks again

Matt

Hi Matt,

Thanks for modifying the ALS cable connection; it was worth a try.

Did you double check to make sure that the spring is installed in the inlet and that you are using the correct insert (it shouldn't have any lines on it, from the set-up that you described).

What ALS injector plunger speed are you using?  If you are using fast plunger speed you could try to change it to slow and see if that has any impact.  You need to expand the injector parameters box (click on the arrow box under washes and pumps) to change the speed.

Can you send me a photo of the Cool on Column inlet and also measure the height from the top of the septum nut to the base and let me know what it is?

Best Regards,

Kristen

Hi Kristen,

Plunger speed is set to slow, have been advised not to use fast. Insert and

spring are in correctly.

Distance between to of nut to base, assuming that you mean mounting plate

the inlet sits on, is approximately 2cm. Just got reference, the S/S sits

~16mm higher than the coc inlet at the point the needle guide meets both

inlets.

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