Tricine buffer for metallothionein isoform separation by capillary zone electrophoresis Original Research Article

Tricine, N-tris(hydroxymethyl)methylglycine, has been used as a running buffer for metallothionein (MT) isoform separation. Effects of tricine concentration, buffer pH and temperature on the separation were studied. Also, the influence of voltage rise time on the MT isoform separation was studied and improvement was achieved by increasing the rise time. Two types of rabbit liver MT samples were used. Method optimisation was performed by using commercial samples. Application to extracted samples from rabbits administered with cadmium was studied. These samples were subjected for capillary zone electrophoretic (CZE) separation under neutral or slightly alkaline conditions. Samples extracted from livers of Cd-administered rabbit showed higher response than the other samples at 250 nm in the UV spectra, wavelength characteristic for Cd–thiol bond. Also, differences in polymorphism were observed. In electropherograms of the samples from livers of Cd-administered rabbits (MT-1 and MT-2) a smaller number of peaks were observed compared to the other samples. Only one peak was observed in both samples, the other samples exhibiting several peaks of varying abundance. From these findings, it was concluded that tricine buffer at pH 8.0 is applicable for MT isoform separation.