To begin, dip three euterpe precatoria seeds and three Euterpe edulis seeds into deionized water for 24 hours. After 24 hours, turn the cryostat on, and let the temperature reach 20 degrees Celsius. Take the wet seeds out of the water and cut them in half using a microtome blade.
Prepare a fresh, warm, 10%gelatin solution. Place half of the seeds on a mold, and fill it with the gelatin solution. Freeze at 20 degrees Celsius for two hours before taking it to the cryostat.
Attach the embedded seed to the cryostat support using an optimal cutting temperature compound, or OCT, and leave it for 10 minutes inside the cryostat for OCT hardening. Next, add copper double-faced adhesive tape to an indium tin oxide-coated glass slide or ITO slide. Produce 20 micrometer thick sections from each species, and place them on the adhesive tape adhered to the ITO glass slide.
For matrix deposition, place the slide containing slices in a vacuum desiccator until it reaches room temperature. Make teaching marks using a correction pen in each slide corner, and scan the slide using a table scanner. Use an analytical balance to weigh 30 milligrams of DHB.
Then prepare a one milliliter solution containing equal parts of methanol and 0.1%trichloroacetic acid, and dissolve the weighed DHB in the prepared solution. Fill a one-milliliter glass syringe with the DHB solution, and place it on a syringe pump with a flow rate of 0.8 milliliters per hour. Using pick tubing, connect the syringe to an atmospheric pressure chemical ionization or APCI needle, and then connect nitrogen to the needle.
Set the flow rate to 12.5 PSI. Attach the APCI needle to the XY motion platform. Ensure that the tip of the APCI needle is four centimeters above the slide.
Using the drawing software, set the XY motion platform to follow the template, and wait for the platform to repeat the template 20 times.
