Locations of radical species in black pepper seeds investigated by CW EPR and 9GHz EPR imaging.
In this study, noninvasive 9GHz electron paramagnetic resonance (EPR)-imaging and continuous wave (CW) EPR were used to investigate the locations of paramagnetic species in black pepper seeds without further irradiation. First, lithium phthalocyanine (LiPC) phantom was used to examine 9GHz EPR imaging capabilities. The 9GHz EPR-imager easily resolved the LiPC samples at a distance of ∼2mm. Then, commercially available black pepper seeds were measured. We observed signatures from three different radical species, which were assigned to stable organic radicals, Fe(3+), and Mn(2+) complexes. In addition, no EPR spectral change in the seed was observed after it was submerged in distilled H2O for 1h. The EPR and spectral-spatial EPR imaging results suggested that the three paramagnetic species were mostly located at the seed surface. Fewer radicals were found inside the seed. We demonstrated that the CW EPR and 9GHz EPR imaging were useful for the determination of the spatial distribution of paramagnetic species in various seeds.
Department of Radiological Life Sciences, Graduate School of Health Sciences, Hirosaki University, 66-1 Hon-cyo, Hirosaki 036-8564, Japan. Electronic address: nakagawa@cc.hirosaki-u.ac.jp.
Kouichi
K
Nakagawa
Department of Radiation and Cellular Oncology, The University of Chicago, MC1105, 5841 S. Maryland Ave, Chicago, IL 60637-1463, USA.
Boris
B
Epel
D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation*; D005609:Free Radicals / Q000032:analysis*; D007211:Indoles / Q000032:analysis; D009942:Organometallic Compounds / Q000032:analysis; D019047:Phantoms, Imaging; D029222:Piper nigrum / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D013113:Spin Labels
D005609:Free Radicals; D007211:Indoles; D009942:Organometallic Compounds; D013113:Spin Labels; C081756:lithium phthalocyanine
EPR; ESR; Free radical; Imaging; LiPC; Pepper