I need to mount multiple cryosected sections proceeding from different tissue samples in close proximity within the same glass slide. In order to thaw-mount both sections in the same glass slide, the first sections - cut from tissue block number 1- sit at room temperature while I cut tissue block number 2.

The main issue I have encountered is that, while I cut the second block of tissue, these first sections suffer analyte delocalisation due to water condensation, consequently interfering with my mass spectrometry imaging data. Furthermore, I've also observed an undesirable increase in apoptotic markers such as cleaved caspase.

Conversely, I've tried to keep the sections within the cryostat chamber, to then warm up with my fingers the part of the slide in which I aim to mount the following sections. The problem here is that, since the samples are quite small and I need them close together, is difficult not to warm up the already-mounted sections upon doing so.

It is worth noting that I can't embed the different samples together in the same cryomold. Also, I'm unsure about submerging the samples in fixative as I cut them because this would likely wash away the drug I'm trying to detect via mass spectrometry imaging.