A Study on the Cd-hem Method for the Simple Determination of Metallothionein in Biological Samples

Abstract

Cd-hem method is the most simple and easy method for the determination of metallothionein (Mt) . In this method, Mt-unbound Cd is removed by a treatment with rat hemoglobin (Hb) and heating at 100 °C. This step is usually repeated 3 times. The authors have carried out several experiments on the Cd-removal process in the Cd-hem method.
Bovine and swine Hbs have a high affinity for Cd and are satisfactorily available for the Cd-hem method instead of the rat Hb. Although Mt is not lost by the treatment with Hb and heating at 100°C, only a single treatment is recommended because it is enough for the removal of Mt-unbound Cd. For the accurate determination of Mt, the value of blank which is determined without biological samples should be subtracted from that of biological samples because the Mt-unbound Cd cannot be removed completely by this treatment even though the treatment is repeated 3 times.