Chromatography Forum

Posted: **Mon Feb 25, 2013 8:33 pm**

Sticky plunger errors are common on the Agilent autosamplers (personal experience). I recommend adding a second syringe wash solution referenced in the June 2007 issue of LCGC North America, volume 25, No. 6, p. 572. The wash solution is N-Methyl-2-pyrrolidone. Please read the MSDS before use. Since I started using it, my sticky syringe errors have decreased dramatically. If you do use this solvent, you will have to test that it does not interfere with your sample analysis since the peak elutes at about 1.5 minutes on a 30-meter DB-23 column. Hope this helps!

Thank you for the recommendation - I will take a look at including that chemical as an extra wash.

Posted: **Tue Feb 26, 2013 3:24 pm**

I would imagine the methanolic KOH from the samples if bad for the syringe - perhaps the NMP for a second wash will address this.

Posted: **Wed Feb 27, 2013 10:41 am**

Another posibility is that the motor has worked loose. At the top of the syringe carrier, just under the plunger motor there is a small wedge, used to adjust the tension on the belt. If this is loose the alignment can go a bit off, which can put enough load on the motor to trip the sticky syringe alarm. Give the wedge a little push. It should click as it goes in. The wedge is notched to give steps, only move it one click at a time.

GCguy

Chromatography Forum

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Re: Back Plunger Error