title: "Distant spin trapping": a method for expanding the availability of spin trapping measurements.
abstract: The technique of spin trapping is used to study a wide range of free radicals in various systems, including those generated in vitro and in vivo. But unfortunately, EPR spectrometers are not always immediately accessible at the site of experimentation, and therefore it is important to find a method that can preserve a radical adduct over longer periods of time. We describe here an alternative method in which the samples can be frozen and transported for EPR measurements at another site. Various spin adducts of DEPMPO were frozen and measured at 0 degrees C at various intervals after freezing to determine their stability in the frozen state. The radical adducts were generated by established methods and stored at two different temperatures; -196 degrees C (liquid nitrogen) and -80 degrees C (dry ice). The experiments were carried out in an aqueous solution with and without a model of reducing environment (2 mM ascorbate). The results indicate that it is feasible to store and transport spin adducts for subsequent analysis. We conclude that this approach, which we term "distant spin trapping", makes it feasible to transport samples to another site for EPR measurements. This should significantly expand the ability to use spin trapping in biology and medicine.
authors.affiliation: Department of Diagnostic Radiology, EPR Center for the Study of Viable Systems, 7785 Vail, Room 702, Dartmouth Medical School, Hanover, NH 03755, USA.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Khan
authors.forename: Oleg
authors.initials: O
authors.lastname: Grinberg
authors.forename: Carmen
authors.initials: C
authors.lastname: Wilmot
authors.forename: Heather
authors.initials: H
authors.lastname: Kiefer
authors.forename: Harold M
authors.initials: HM
authors.lastname: Swartz
mesh_terms: D003497:Cyclic N-Oxides / Q000737:chemistry / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D005609:Free Radicals; D005615:Freezing; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017665:Hydroxyl Radical; D007053:Ice; D007501:Iron / Q000494:pharmacology; D007700:Kinetics; D008956:Models, Chemical; D009584:Nitrogen; D013048:Specimen Handling; D013113:Spin Labels; D019097:Spin Trapping / Q000295:instrumentation* / Q000379:methods*; D013447:Sulfites / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D003497:Cyclic N-Oxides; C045076:Fenton's reagent; D005609:Free Radicals; D007053:Ice; D013113:Spin Labels; D013447:Sulfites; D013481:Superoxides; C098505:5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; D009584:Nitrogen