Rare-earth element complexes with complexones, heparin, and antibiotics in biosystems for use as electrode-active materials in membrane ion-selective electrodes

Objectives . The creation of ion-selective electrodes (ISEs) based on rare-earth element (REE) complexes in environmentally friendly biosystems is of interest due to the increased relevance of environmental management. The work sets out to study the possibility of using REE complexes for creating ISEs sensitive to cefazolin. The created potentiometric sensors can be used for rapid determination of antibiotics in microvolume samples. Methods . The work presents the synthesis of electrode-active REE complexes with cefazolin. In order to identify the obtained electrodeactive substances and investigate their physicochemical characteristics, the following methods were used: elemental analysis with a scanning electron microscope, infrared spectroscopy, simultaneous thermal analysis, and potentiometry. Results . Previously unstudied complexes of cerium and lutetium with cefazolin were obtained for use as an electrode-active substance for creating ISEs. The physicochemical characteristics of the complexes were investigated. For the created ISEs, the following characteristics were studied: performance characteristics, the dependence of electrode potentials on the analyte concentration, stability, and the response time of the electrode placed in the sample under study. The created membrane electrodes are stable, have a concentration range of operation of pC 1–3, and can be used in the pH range 4–8. Testing of the selectivity of the ISEs with respect to Na + and K + ions showed that the electrodes are effective even in a thousandfold excess. The performance of the electrodes was tested using model systems. Conclusions . Novel REE–cefazolin complexes were successfully demonstrated for use as electrode-active substances for the manufacture of membrane ISEs sensitive to cephalosporin antibiotics.