Please provide feedback on my issue. I work with GC/FID-NPD Trace 1310 with autosampler Triplus RSH (Thermo). I use standard liquid injections, but from the beginning I´ve faced problems that the autosampler breaks the syringe plunger. At first, the device works as it should, but for example on the twentieth injection, the piston breaks. Sometimes the breaking occurs immediately after picking of the tool and first injection. I provide a photo of what the syringe looks like after breaking. My local service technician claims that a barrier will appear in the syringe and pressure on the plunger by the autosampler will break the plunger. He also claims that the problem is caused by the solvent (dichloromethane), which causes corrosion of the piston. Triplus RSH allegedly does not cause a problem and is not defective. However, in my view, the piston is clean after it breaks, there are no black spots or something. Based on the techniciands advice for more cleaning of the syringe, I adjusted the settings of Triplus RSH as I state in the attached photos. The washings are always methanol, hexane before injection, and hexane, methanol after injection. So far, I only work with standards of liquid substances diluted in dichloromethane or hexane, so I don't have dirty samples. I believe, I wash the syringe more than I should need. I also clean the syringe manually every day. I also tried to replace the plunger in the syringe with a plunger from a Hamilton syringe (I had to replace the upper plunger catch), but over time the same problem occurred. I don't think Thermo syringes are of such poor quality that this should happen. Please advise if anyone at Triplus RSH has encountered the same problem or has an idea how to resolve the situation.
As a user of RSH for the past two years, this only happened once to me.
To have it happen this much frequently to you, there is definitely a problem.
You can try this suggestion: Have a vial filled by Methanol (Pure). Make a sequence of 25 or more repetitive injections of this vial. Methanol itself should not make the inside of the syringe body sticky neither corrodes the piston. If these 25 injections complete without any problem, then it is clear that you must investigate your sample and the solvent compatibility with the piston's materials.
However, if the syringe breaks again, you should insist on a solution from ThermoFisher. This could be a faulty robotic arm which applies extra force when aspirating the sample.
I looked at your syringe's picture, and it shows me that you are using the right one for the RSH autosampler.
Try that suggestion and let us know what are the outcomes.
Dear Dr. Jaderson, Thank you for your response. I use methanol to wash the syringe, as you can see in the included autosampler setup. I can, of course, try the test you are proposing, but I find it very strange that hexane would cause such severe corrosion of the piston. I can't use only methanol as a solvent in GC, and the autosampler can't limit my work like that. All solvents I use are GC/FID purity or higher. I thought there would be a problem with the Thermo syringe pistons, so I swapped the piston for another one from the Hamilton syringe, but the problem occurred again after a longer sequence.
Hi Tomas
Have you solved the problem? Can you share an update please?
I solved the problem by stopping using Thermo syringes. I don't think it's an ideal solution to the problem, because these syringes are widely used and apparently users don't have such problems with them like I do. I use pistons from Hamilton syringes, and I put this piston into the Thermo syringe (the Thermo syringe has a special hold at the top and syringes from other manufacturers would not be compatible with the autosampler).
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