Avoiding Contamination of Ultra-Thin Sections

Contamination of Ultra Thin Sections

Contamination of ultra thin sections is a source of frustration when doing TEM. If contamination is caused by uranyl acetate and/or lead citrate(lead acetate) staining, do not despair. Hilton H. Mollenhauer (JEMT 5:59-63, 1987) suggested two ways to eliminate staining precipitation. One of the ways is as follows: Place each nickel or copper grid (with section) on a drop of 0.5N HCl for 0.5 minutes for Lowicryl K4M sections or for 1-2 minutes for Epon 812 (or replacement) sections. Then rinse each grid in deionized water and blot dry on filter paper. Now you can restain with uranyl acetate and/or lead as the HCl does have a tendency to bleach the sections.

Suzanne J. Botkin. “A Staining Tip” EMSA Bulletin 22:3 Nov. 1992.