Magnetite as a Versatile Material – Application as an Electrochemical Sensor in the Determination of Sucralose and Perilartin in Drinks and as an Adsorbent for Uranium – Theoretical Description

The iron oxides deserve special attention due to their distinguished features, e.g., magnetism and pervasiveness. These oxides exist in various forms and find applications in many branches of industry. Nevertheless, most studies deal with magnetite (Fe
3
O
4
) and maghemite (Fe
2
O
3
), wherein the first one is more common. Magnetite is a mineral with metallic sheen. Its structure is composed of both Fe (II) and Fe (III) ions with a 1:2 ratio. This mixed oxide displays excellent magnetic properties and electrical conductivity. Magnetite occurs naturally in rocks and can be transformed into other forms. In turn, maghemite is built of Fe (III). This mineral is unstable in the environment and can convert into the hematite form at higher temperatures. The magnetic properties exhibited by iron oxides could be a vital factor that is crucial for any potential possible applications, e.g. in medicine, adsorption, industry. In the experiment the co-precipitation method was used to obtain iron oxide. The material was analyzed utilizing the following methods: XPS, SEM, ASAP. Moreover, the zeta potential was also measured as well as surface charge density in potentiometric titration method. In this approach the original computer program titr.v3 created by Professor Wladyslaw Janusz was used. The experiment with uranium ions adsorption on the iron oxide was also conducted and it showed high adsorption efficiency. The concentration of uranyl ions in the equilibrium solutions was determined by the spectrophotometric method. The uranium ions binding process can be assumed as mixed. It can be concluded that the iron oxide could be a good adsorbent for uranium ions. The theoretical calculations of the adsorption of uranium ions on the iron oxide surface have been carried out. Other interesting applications of magnetite is electrochemical sensor. Perillartine (perillaldehyde anti-aldoxime) is a natural sugar substitute, extracted from Japanese perilla (shiso) leaves. Besides of the proper perillartine, its ether derivative is also used, despite of being much less sweet than the proper perillartine (possessing the sweetness, nearly equal to that of aspartame). This oxime is bioavailable and biodegradable. It may be allergic for people allergic to shiso herb. Also, some toxic nitrogen derivatives like hydroxylamine may form during its metabolism in some people. It is important to mention that perillaldehyde aldoxyme and its derivatives are rarely used as sweeteners outside Japan, so this statement may be used in investigation of falsification of allegedly Japanese product claimed to contain the peryllartine. Thus, the development of an efficient, exact and rapid method for perillartine determination is really actual task, and the electroanalytical methods would give it a good service. In this work, the electrochemical determination of sucralose and perilartine in beverages on Fe
3
0
4
-modified electrode has been theoretically described.