Hematoxylin Plasma Treatment

Although it is common practice to use hematoxylin as the source of dye, it is not itself the actual dye and it has to be oxidized to hematein, which is a dye, before it can be used. This process is called ripening, and can be accomplished in two distinct ways. The ripening is usually accomplished with chemical oxidizing agents, but is sometimes accomplished by atmospheric oxygen over time. Hematein is not incorporated directly in most staining solutions because it continues to oxidize in solution and forms non-staining products. The quality of hematoxylin is usually higher and more consistent than the quality of hematein, and solutions made with it are more easily standardized. Many technologists believe that natural ripening by atmospheric oxidation is the best, and gives a more reliable and longer lasting solution. Natural ripening is accomplished by putting the solution in an oversize flask, so it can be shaken, with the top plugged loosely with cotton wool, allowing air to enter. This is left in a warm, light and airy place (a windowsill) for oxidation to take place. The flask is shaken periodically. Oxidation may take several months, and is determined by testing the solution from time to time. The other way to ripen hematoxylin is to use chemical oxidizing agents. The most commonly used is sodium iodate, at about 200 mg per gram