Gualtieri Giancaterino, Colacicchi Silvia, Carnicelli Veronica, Di Giulio Antonio
Department of Biomedical Sciences and Technologies, University of L'Aquila, Italy
Biophys Chem. 2005 Apr 22;114(2-3):149-55. doi: 10.1016/j.bpc.2004.11.014. Epub 2004 Dec 10.
The effects of either static or pulsed magnetic fields on the reaction rate of Fremy's salt-ascorbic acid were studied directly by EPR spectroscopy. Radical pair mechanism (RPM) accounts for the magnetic field effects, but the expected amounts are so small that they need to be observed with particular care with EPR technique. The method is based on the resolution of a pair of EPR signals by the addition of a stationary field gradient, where the signals are coming from the exposed and control capillary sample. To this purpose, a suitable device for the gradient generation was used. Others improvements were the strictly keeping of the same boundary temperature condition in the capillary pairs, obtained by a refrigerating system controlled by a thermocouple, and the use of a pair of Helmholtz coils to generate an external high homogeneous magnetic field. By this experimental set up, we found that the magnetic field induce the decrease of the studied radical reaction rate. This EPR approach is a significant alternative to the spectrophotometric one. Moreover, it offers the advantage to detect both the radicals and/or intermediates involved in the reaction.
通过电子顺磁共振光谱法直接研究了静态或脉冲磁场对弗雷米盐 - 抗坏血酸反应速率的影响。自由基对机制（RPM）解释了磁场效应，但预期的变化量非常小，以至于需要使用电子顺磁共振技术特别仔细地观察。该方法基于通过添加静态场梯度来分辨一对电子顺磁共振信号，其中信号来自暴露的和对照毛细管样品。为此，使用了一种合适的梯度产生装置。其他改进包括通过由热电偶控制的制冷系统在毛细管对中严格保持相同的边界温度条件，以及使用一对亥姆霍兹线圈来产生外部高均匀磁场。通过这个实验装置，我们发现磁场会导致所研究的自由基反应速率降低。这种电子顺磁共振方法是分光光度法的一种重要替代方法。此外，它具有检测反应中涉及的自由基和/或中间体的优势。
