I'm not sure if anyone will have an answer to this, but here goes.
My professor and I are trying to study neural responses in brain tissue. However, everytime we fill our recording pippette, we find (under 60x magnification) that there is a tiny crystal blocking the tip. We have tried cleaning our syringes, using/not using syringe filters, different fine tips, using a new, clean tip every time, nothing seems to work. Occasionally, we find fewer crystals with one alloquot of internal solution, but most of the time (~9/10) there is a crystal.
Has anyone ever seen something like this? Does anyone know of a solution?