I have experienced problems with the SPME needle, in fact it happens very often that the needle is not able to punch the septum, and it is bent. The system is working well, nothing is changed in the method, the spare parts are the same (I mean same lot of septa, same lot of SPME fiber), the alignment is perfect (in fact it happens in the right position), the tension cords have been replaced...
The only thing I can think about, after several trials, is the electronic crimper that might not properly close the vials, because it is not fully charged... it has never happened before to me (I have been using this system for years), but I have no alternative ideas.
So I would ask if anybody has already experienced the same, and any suggestion will be more than welcome!
In the past, I have experienced similar with other autosampler. The issue was quite simply, that the lids on the vials were too tight. By tightening too much (especially when using a crimper) can make tension in the septum too great and also result in the septum curving upwards. That makes it difficult for the needle to achieve efficient penetration and sometimes "sliding" off just a little on the surface. As force is continuously applied downwards, the needle will often bend.
My advice is trying to see if your lids can rotate lightly on the vials. If not, adjust the crimper so that they can. That solved the problem in my old lab.
I would say the most likely issue is what Simon mentioned. I also had it in the past.
Thank you very much for your answers.
It seems to me that the vials were not tightly closed, but your experieces tell me that the issue is not negligible.
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