GC headspace autosampler G1888 issue

[maldiniyan]

Hi, guys. We have an Agilent headspace autosampler G1888 hooked up with an Agilent 7890 GC.

Recently we have been experiencing a weird issue with the autosampler's sample probe lifter. Now every time when we ran the samples, the vials were taken into the carousel fine, but after sampling probe was injected into the vial cap, the sampling probe couldn't completely retract back to its original position and still connect with the vial, blocking the rotation of the carousel, sample vials stuck inside and the sequence stopped. I tried to reset the autosampler, but the sampling probe still stick out.

Have some had the same issue before and can give some advise?

Thanks!

[scottythree]

Not sure if this is your issue or even if this can be an issue if it is incorrect but check to make sure you have the right vial size (10 mL or 20 mL) selected (under advanced options).

[maldiniyan]

Not sure if this is your issue or even if this can be an issue if it is incorrect but check to make sure you have the right vial size (10 mL or 20 mL) selected (under advanced options).

The vial size (20 mL) is correctly selected, but it doesn't help.

[lcgcscientific]

First, if you haven't already done this, check the carousel alignment. I would also remove the sample probe and make sure it is not bent.
If the lifter is aligned properly to the hole you may need to clean and lubricate the lifter.
Getting to the lifter is the fun part.

[Peter Apps]

I never actually used the 1888 model, but in its descendents and other models of vial and loop headspacer it is the vial that moves, not the needle. The vial is lifted up onto the needle by a ram that runs though a hole in the bottom of the sample platen. The vial is pushed off the needle by a spring loaded plate around the needle. If your vials are stuck on the needle it may be beacause the spring is weak or broken, the plate if jammed, the needle is bent, or you are using a particularly grippy type of septum. Some butyl rubber septa really hold onto the needle, silicone septa less so.

Peter

[maldiniyan]

I never actually used the 1888 model, but in its descendents and other models of vial and loop headspacer it is the vial that moves, not the needle. The vial is lifted up onto the needle by a ram that runs though a hole in the bottom of the sample platen. The vial is pushed off the needle by a spring loaded plate around the needle. If your vials are stuck on the needle it may be beacause the spring is weak or broken, the plate if jammed, the needle is bent, or you are using a particularly grippy type of septum. Some butyl rubber septa really hold onto the needle, silicone septa less so.

Peter

I also think it's very likely the spring is broken. I want to disassemble the sampling probe needle mount to check inside but Agilent technical support won't give me any instruction. Does anyone here know is it possible or too difficult to disassemble it? Thanks!

[maldiniyan]

Problem solved. It's not the spring, but the needle guide. After years' use, the sampling probe hole in the middle of needle guide is worn out, preventing the probe moving in and out. Cost for a plastic needle guide is $260, ridiculous, but still much cheaper than $6000 that Agilent's solution of replacing the whole module.

I never actually used the 1888 model, but in its descendents and other models of vial and loop headspacer it is the vial that moves, not the needle. The vial is lifted up onto the needle by a ram that runs though a hole in the bottom of the sample platen. The vial is pushed off the needle by a spring loaded plate around the needle. If your vials are stuck on the needle it may be beacause the spring is weak or broken, the plate if jammed, the needle is bent, or you are using a particularly grippy type of septum. Some butyl rubber septa really hold onto the needle, silicone septa less so.

Peter

I also think it's very likely the spring is broken. I want to disassemble the sampling probe needle mount to check inside but Agilent technical support won't give me any instruction. Does anyone here know is it possible or too difficult to disassemble it? Thanks!

[Peter Apps]

Thanks for the feedback. And I have to agree that the prices for a lot of spares are absurd.

Peter