Mobile phase leakage through needle in autosampler Shimadzu

[tedjoc]

We recently purchased an older Shimadzu HPLC (circa 1990s) and we are having troubles with getting rid of bubbles from the system, we finally suspect that the bubbles may come out of the injector. I was told that the needle may need realignment. Today after alignment, I turned on the pump to flush bubbles that I saw on the detector line (after injection). Liquid was not moving and I saw that liquid was coming through the needle in the autosampler. Before this I have noticed liquid droplets on the needle but I thought it was normal. This is the first time I use autosampler. I looked up only this may be a cross port leak. Am I correct? if yes, what should I do to fix this other than contacting the company that sold this system (they are not being helpful)? Thanks

[DR]

First, I assume that your needle has a stainless line feeding it and that it is seated in a high pressure polymer seal (If you have a translucent line feeding the needle, it's a different problem...).

If putting a new high pressure seal in does not stop the leakage, then you need to contact a Shimadzu field service engineer and have them come and make the adjustment for you. They'll probably be willing to show you how to do it while they're there. If you're mechanically inclined and have an advanced user of same kit as a friend, or are very friendly w/ a service engineer w/ Shimadzu experience, they may be able to talk you through the procedure.

[uzman]

Which model do you have ? Is it SIL-6A or 6B ?

Both SIL-6A and 6B autosamplers do not have needle seats as newer models.
They simply suck the sample by using a syringe and fill the sample loop by a 6 port valve.

Most of the problems ( leaks , suction problems ) originate from the rotor seal inside the 6 port valve.

Another problematic part is the solenoid valve used to control the suction and wash cycles.

6A model has one 24 volts solenoid valve and 6B model has two 12 volts solenoid valves.

Simply changing the rotor seal and solenoid valve(s) should solve most of the problems.

[tedjoc]

Hi, the model that I have is SIL-10ADvp. Thank you

Which model do you have ? Is it SIL-6A or 6B ?

Both SIL-6A and 6B autosamplers do not have needle seats as newer models.
They simply suck the sample by using a syringe and fill the sample loop by a 6 port valve.

Most of the problems ( leaks , suction problems ) originate from the rotor seal inside the 6 port valve.

Another problematic part is the solenoid valve used to control the suction and wash cycles.

6A model has one 24 volts solenoid valve and 6B model has two 12 volts solenoid valves.

Simply changing the rotor seal and solenoid valve(s) should solve most of the problems.

[uzman]

SIL-10ADvp is a different story.
It has a needle seat , the needle is a part of flow path and continuously washed with mobile phase .
If the needle seat does not properly seal , leakage will be obvious.

Other leakage points are metering valve , located at the bottom right hand side of the autosampler and the 6 port valve .

Change : needle seat , plunger and plunger seal at the metering valve , rotor seal at the 6 port valve ; depending on the leakage point.

Also check the tubing connection nuts and fasten them a little bit more , or change the ferrules if necessary.

[Camisotro]

SIL-10ADvp is a different story.
It has a needle seat , the needle is a part of flow path and continuously washed with mobile phase .
If the needle seat does not properly seal , leakage will be obvious.

Other leakage points are metering valve , located at the bottom right hand side of the autosampler and the 6 port valve .

Change : needle seat , plunger and plunger seal at the metering valve , rotor seal at the 6 port valve ; depending on the leakage point.

Also check the tubing connection nuts and fasten them a little bit more , or change the ferrules if necessary.

Had a similar issue recently on an Agilent 1260 autosampler with a needle seat. We happened to have two identical units (one for LC/UV, other for LC/MS) so we tried swapping needle seats and it worked - so that was indeed the site of the problem. Bought a replacement part. Easily user-serviceable. I don't know if the analogous part for Shimadzu is easily user-serviceable.