[Methods of nanoparticles control in food and biological objects. Report 1. Use of microscopic and chromatography investigation methods].

One of the promising applications of modern nanotechnology are food productions, which includes the improvement of food packaging, creation of new forms of nutrients that are characterized by improved assimilation and technological characteristics, quality control through the creation of compact and cheap test kits. All these applications of nanomaterials related to the risks of the possibility of receipt of potentially toxic nanoparticles in the diet. The task of regulation and hygienic standardization requires developing of the methods, their qualitative and quantitative analysis for such complex, multicomponent systems, which are the agricultural commodities and food products. The best hope in this plan are assigned to a group of approaches related to the microscopic visualization of artificial nanoparticles in the biological objects. While the typical size of nanoparticles (<100 nm) are below the theoretical maximum-resolution light optical methods, transmission electron microscopy often allows not only to identify nanoparticles on their size and shape, but also a qualitative and quantitative analysis their chemical composition with the use of additional analytical options. Another group of elaborate methods used in solving the problems of qualitative and quantitative analysis of nanoparticles are chromatographic methods, in particular, the exclusion, hydrodynamic, high-performance liquid chromatography, and the flow-field fractionation. Limitation of chromatographic approaches related with the need of complex sample preparation, as well as specific difficulties in nanoparticles detecting in chromatographic fractions. Transmission electron microscopy and high-performance liquid chromatography methods are officially recommended in Russia for the analysis of artificial nanoparticles in natural biological systems, including food products.

[Characterization of silver nanoparticles migration from package materials destined for contact with foods].

There was studied migration of artificial silver nanoparticles from polyethylene films destined for package of such foods as bread and poultry into model media reproducing physico-chemical properties and composition of said products. Modification of films was performed by 5- or 10-fold spraying of silver nanoparticles on the surface of package material. Model media were composed from water, alcohol and plant oil according to US FDA and Russian Federal Service for Surveillance of Consumer Rights Protection and Human Well-Being official recommendation. Nanoparticles were detected in model media by means of transmission electron and atomic force microscopy. Quantification of silver in nanoparticles migrating from films was performed by mass-spectrometry with inductively coupled plasma. The results obtained showed that silver migrated from films into test media in form of nanoparticles with mean diameter close to 10-20 nm. Migrated particles were partially aggregated to complexes with dimension about 50 nm with degree of aggregation depending on media composition. Quantification showed that amounts of silver nanoparticles migrating in foods did not exceed save level of this nanomaterial consumption even in aggravated conditions when almost all volume of product was consumed in form packaged in films modified with nanosilver.