The hematoxylin (Greek haimatus: blood, and xylon: wood) it is a natural substance obtained from the leguminous plant Haematoxylum campechianum. Hematoxylin has to be oxidized to become hematein, which is actually the dye, and combined with a metal that works as a mordant. The oxidation can be done in the lab by chemical oxidation or let it be oxidized by atmospheric oxygen. Hematein is a basic dye that stains nuclei, commonly combined with eosin in standard histology techniques, but also in other staining procedures such as trichromic stainings.
Procedure
6 g Heamatoxylin (C.I. 75290)
300 ml 100º ethanol
300 ml distilled water
300 ml glycerol
30 ml Glacial acetic acid
30 g Aluminium potassium (or sodium) sulfate (= potassium alum)
0.9 g Sodium iodate
Notes
Dissolve the hematoxylin in ethanol before, and then adding the other components in the sequence stated above.
Sodium iodate is the oxidizing agent so that the solution can be used immediately. The solution can also be left for two months for air oxidation. It is a slow process, but it provides a good-quality staining, and the solution can be used for years.
The amount of potassium alum has to be enough to get a saturated solution. Actually, it is enough when potassium alum precipitates can be observed at the bottom of the flask. It means that the solution is saturated.
The staining time may be about 2 to 4 min
Products
Distilled water
Aluminium potassium (or sodium) sulfate (= potassium alum)
Hematoxylin (C.I. 75290)
Sodium iodate
Glycerol
Glacial acetic acid
Labware
Test tube
Balance
Magnetic stirrer
Flasks
Bottles