Potentiometric studies of selective reactions of bioactive substances on the surface-modified tantalum electrodes.

The method of highly selective potentiometric detection of bioactive substances developed by us has been much improved by using tantalum metal as a electrode material, by employment of a new method of modification (using gamma-aminopropyltriethoxysilane and cyanogen bromide), and by the pretreatment with inert protein before the measurement. As the consequence, the response in the electrode potential shift has been increased and the reproducibility of the data reached almost 100%.

Potentiometric and spectroscopic studies of the reaction between trypsin and its inhibitors on chemically modified solid surfaces.

The potential of a titanium metal electrode modified with trypsin changes as a result of the complex formation reaction between trypsin and its inhibitor, aprotinin, dissolved in the solution. A similar potential change in the opposite direction occurs by the reaction between aprotinin-modified electrode and trypsin in the solution. The induced changes in both cases depend on the pH of the solution, showing the maximum change at pH = 9.

Antigen--antibody reaction investiaged with use of a chemically modified electrode.

The antigen-antibody reaction of human choriogenadotropin has been potentiometrically investigated by use of a cyanogen bromide-treated electrode coated with the corresponding anti-serum. The potential of the modified electrode shifts in the positive direction upon contact with a solution of choriogonadotropin. The rate of the reaction at the interface between the electrode and the solution is estimated from the potentiometric measurement to be of the order of 10(4) mol-1 s-1 in diethyl barbiturate buffer, depending to some extent on the rotation speed of the stirrer.

Potentiometric investigations of antigen-antibody and enzyme-enzyme inhibitor reactions using chemically modified metal electrodes.

The electrical potential between an immunoreactive electrode and a reference electrode in a buffer solution was studied. The immunoelectrode was made of titanium wire, on which an antigen or an antibody was chemically fixed. The electric potential of the electrode sensitized with anti-hCG gamma-globulin shifted in the positive direction in the presence of a small amount of hCG in the solution.