An Extemporaneous Lead Citrate Stain for Electron Microscopy

The use of lead stains for thin sections in electron microscopy is widespread. Of the various compounds, lead citrate is commonly employed. However, Reynolds' technique for its preparation from lead nitrate and sodium citrate is time-consuming. With the availability of lead citrate commercially, from at least two suppliers (K & K Laboratories, Inc., Plainview, N. Y. and Polyscience, Inc., Rydal, Pennsylvania, 19046) we have investigated the suitability of this commercial form for the staining of thin sections. We attempted to develop a technique for the simple and instantaneous preparation of a staining solution to be used fresh each time and then discarded. Following multiple trials at various concentrations, we formulated its preparation in a “cookbook” fashion involving a minimum of weighing and measuring. Previously boiled, cooled, double-distilled, millipore-filtered water, which can be stored in the refrigerator, is used. To 50 ml. of water add one pellet of sodium hydroxide (Merck) and stir until dissolved.