ИСТИНА

Reusable solid thin film sensors based on Langmuir-Schaefer (LS) multilayer structurs of new series of (trans-A2)BC-type porphyrins with acceptor diethoxyphosphoryl and heteroatom-containing donor groups for selective determination of mercury (II) cations in aqueous solutions is reported (Fig. 1). A film of just ten layers allows one to observe color changes at binding of mercury (II) cations from aqueous solutions. It was found that the heteroatom (O, S, N) bound to a porphyrin macrocycle affects the structure of the Langmuir-Schaefer films and binding time of mercury (II) cations by these film sensors. The morphology of the films was investigated by scanning electron microscopy (SEM) (Fig. 1c). The quality of films deposited on the surface of gold and their restructuring upon binding of Hg2+ was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Interesting that only solid LS films sensors are demonstrated an excellent selectivity for mercury (II) cations in contrast to solutions and Langmuir monolaers of porphyrins at the air/water interface due to the immobilization of molecules on solid substrate fixing a structure that is complementary to mercury (II) cations.