Uranyl Formate Stain Preparation for Negative Staining EM.
Any trash generated during this procedure must be disposed of as a combined hazardous waste in the EM Prep area. The container label should read Radioactive hazard boxes should be checked.
- Weigh 37.5 mg of uranyl formate (50 mg for small proteins)
- Put it into a very small glass beaker
- Cover the uranyl formate with aluminum foil at all times
- Boil 5 ml ddH2O in a test tube using Bunsen burner (Fisher Sci 10-310-200)
- Pour boiling water into the beaker (10 ml glass beaker)
- Mix it with a small stirrer bar for 5-10 minutes
- Add 1 µl of 5 M NaOH per exactly 6 mg of uranyl formate to adjust the pH (6.25 µl for 37.5 mg)
- Mix another 5-10 minutes
- Filter the uranyl formate solution with 0.1 or 0.2 µm fresh, good quality filter, cover with foil.
Uranyl formate (UO2(CHO2)2·H2O) is a fine yellow free-flowing powder Cat#24762 PolySciences
Another protocol can be found at Grigorieff Lab. webpage