Modified Trump’s universal fixative

Recipe

Reagent	Quantity (for 40 mL)	Final concentration
Cacodylic acid	0.56 g	100 mM
Paraformaldehyde (16%) (Electron Microscopy Sciences; sealed ampoules)	10 mL	4% (w/v)
Glutaraldehyde (8%) (Electron Microscopy Sciences; sealed ampoules)	5 mL	1% (v/v)
MgCl₂ (1 M)	80 μL	2 mM

Add the cacodylic acid to ~20 mL of water. Adjust the pH to 7.2 with NaOH. Bring the volume to 25 mL with H₂O. Add the paraformaldehyde, glutaraldehyde, and MgCl₂. Make this fixative fresh immediately before using.