Electrochemistry and molecular modeling of the hemoglobin-benzene interaction with a nanocrystalline mixed metal oxide

Nanocrystalline mixed metal oxides of various metal cations were synthesized and were then used for the construction of a new modified carbon paste electrode. Hemoglobin (Hb) was entrapped on the surface of this electrode using an alginate biocompatible biopolymer that crosslinked with the calcium ions. Spectroscopic studies were done to determine the characteristics of the biopolymer matrix and the effects of benzene on Hb. The direct electrochemistry of Hb using the proposed method and its application in Hb interaction with benzene were investigated using an electrochemical method. The heme complexes with imidazole and histidine were also entrapped on the surface of the electrode and the effect of benzene on these complexes was also studied. The Hill binding parameters were obtained for the Hb-benzene, imidazole-heme-benzene and histidine-heme-benzene interactions. A molecular docking simulation was used for theoretical studies and the data obtained were compared with experimental results. A good agreement was observed between the theoretical and experimental results. The Hb electrode can be used for benzene determination in water and aqueous solutions because of the linear relationship between benzene concentration and the peak current decreases with good linearity. The proposed sensor has advantages such as it has an easy, simple and inexpensive preparation method, shows good linearity and low detection and good quantification limits, good reproducibility and sensitivity, and has a relatively long life time (about 15 days) that is because of the alginate biopolymer biocompatible matrix.