The alum hematoxylins I've worked with required daily filtration. An iridescent scum on top of the hematoxylin means you're overdue to filter.
When you brew a fresh batch of alum hematoxylin, it's a light yellow color. As it oxidizes (slowly if you depend on atmospheric oxygen, instantly if you add an oxidant such sodium iodate or mercuric oxide) it turns into deep purple hematein (say hee-muh-TEE-in, not the same as hematin) which is what you stain with. Hematein oxidizes further to filterable crud. Whatman No.1 filter paper is fast and easy to get, and is usually preferred. Sometimes Good Management Practice requires substituting a paper towel, which works reasonably well. You young whippersnappers shouldn't need to be told this by a 76 year old pathologist! Bob Richmond Samurai Pathologist Maryville TN _______________________________________________ Histonet mailing list [email protected] http://lists.utsouthwestern.edu/mailman/listinfo/histonet
