Stock Solutions

  • 100% Anhydrous Ethanol (EtOH)
  • 100% Anhydrous Methanol (MeOH
  • Na methoxide (Sigma-Aldrich) or aged Na ethoxide:
    • Aged Na ethoxide: Place ( 1 inch of NaOH pellets in a heavy glass 500-1000 ml bottle with a glass stopper covered in Parafilm. Cover the pellets with ( 3 inches of EtOH, seal and place in the hood. Shake daily until the solution becomes dark brown and syrupy (7-14 d), whence it is ready for use. Add replacement EtOH as the stock is used. Mark as an extremely hazardous, caustic reagent.
    • Na Methoxide: 50:50 Na methoxide and MeOH. Mark as an extremely hazardous, caustic reagent.


  1. Working solution: Dilute stock Na methoxide/ethoxide 1:4 v/v in anhydrous EtOH. It is critical that all solutions be absolutely anhydrous. If you doubt the 100% EtOH, don’t use it.
  2. Place slides into glass or steel carriers (not plastic) and immerse in the working solution. The general etching time is 14 min/micron and is linear (e.g. 30 min for 2 microns, 7 min for 500 nm, 1 min for gold 90 nm sections). Note that the working solution can be used for several days if kept anhydrous.
  3. Drain the excess solution by blotting the carrier onto a stack of paper towels.
  4. Immediately immerse in 100% EtOH or MeOH and wash 2 min. Repeat 3X with fresh alcohols.
  5. Rinse slides 5 min in running cool tap water
  6. Dip slides in dH2O and air dry.

Disclaimer: As conditions of use are outside our control, we make no warranties, express or implied, and assume no liability in connection with use of this protocol.

This protocol may be copied and distributed for educational and non-profit
purposes as long as acknowledgement of our copyright is included
in every instance of use. It may not be sold or distributed for commercial gain.