Prospects for the application of the electron paramagnetic resonance method for the identification and dose assessment of irradiated food products

Работа рассматривает мировой опыт по исследованию радиационно-обработанной пищевой продукции методом электронного парамагнитного резонанса (ЭПР). Работа проведена с целью оценки перспективности применения метода ЭПР-спектрометрии для идентификации радиационно-обработанной продукции при оценке качества продукции, поступаемой на продовольственный рынок. Метод ЭПР-спектрометрии заключается в идентификации и дозовой оценке радиационно-обработанной и необработанной продукции методом анализа ЭПР-спектров исследуемого образца. Рассмотрены ЭПР-спектры основных видов исследуемых продовольственных продуктов (мясная и рыбная продукция, свежие овощи и фрукты, специи, сухофрукты и орехи). Определены основные параметры ЭПР-спектра, являющиеся маркерами облучения продукции (амплитуда и ширина пика, отношение сигнал/шум, g-фактор). Выявлены основные факторы, влияющие на внешний вид ЭПР-спектра (доза облучения и время, прошедшее после облучения, плотность исследуемого продукта, его атомное и молекулярное строение, химический состав). По итогам проделанной работы планируется создание базы данных, включающей в себя сведения об облученной продукции, основных характеристиках ЭПР-спектров, библиографическую справку и др.

Dipolar Coupling-Based Electron Paramagnetic Resonance Method for Protease Enzymatic Characterization and Inhibitor Screening

Herein, we report an EPR-based method for protease enzymatic characterization and inhibitor screening. This method utilizes dual paramagnetically-labeled probes consisting of a nitroxide spin probe and a Gd3+ ion flanking...

Compensating H+ and Li+ ions in quartz structural channels of the gold fields of Darasun ore field (Eastern Transbaikal, Russia): electron paramagnetic resonance data

The composition and diffusion mobility of the compensating ions in the quartz structural channels of the gold fields in the Darasun, Teremkinskoye, and Talatuy gold fields of the Darasun ore field were examined using the electron paramagnetic resonance method. The assessment of the properties and peculiarities of the ion distribution in quartz was based on their ability to participate in the neutralization of the electric charges of the structural defects occurring in the minerals. In this regard, the ion composition was evaluated by the ratio of the concentrations of the Ti-centers using various compensators. Their mobility was determined by the center formation rate during the quartz radiation exposure. The research demonstrated the availability of two major compensating ions, H+ and Li+, in the quartz structural channels of the gold fields in the Darasun ore field. The diffusion mobility of the H+ ions in the channels was observed to be 1–2 orders of magnitude higher than that of Li+. The correlation link between the compensating ions in the mineral and fluid compositions was not obtained based on the data analysis. A difference was identified between the ratio of the H+ and Li+ concentrations in the quartz structural channels of different fields. Further, the highest concentration of H+ ions and the lowest concentration of Li+ ions were recorded for the quartz in the Darasun field; the inverse correlation was observed for the quartz in the Talatuy field, which can be attributed to the mixing of the fluid gas component during the ore formation process. The electron paramagnetic resonance method can be used for the quantitative assessment of the degree of quartz dynamic recrystallization.

Probing electron transfer between hemin and riboflavin using a combination of analytical approaches and theoretical calculations

Proton-coupled electron transfer mechanisms of riboflavin bound hemin in aqueous solution are elucidated by spectroelectrochemical analysis, the electron paramagnetic resonance method and theoretical calculations.