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. Author manuscript; available in PMC: 2021 Nov 20.
Published in final edited form as: Free Radic Biol Med. 2020 Jul 30;160:630–642. doi: 10.1016/j.freeradbiomed.2020.07.032

Fig. 3: EPR spin trapping of superoxide (O2•−) by DMPO with increasing [GC4419].

Fig. 3:

O2•− was generated by the xanthine oxidase/xanthine system in the presence of 50 mM DMPO with the GC4419 concentrations noted of 0, 2, 5, 10 and 20 μM (A). A strong DMPO-OOH signal is seen that is quenched with increasing [GC4419]. A small signal of DMPO-OH is also present. Computer simulation of the experimental spectrum with 0 μM GC4419 as a combination of DMPO-OOH and DMPO-OH adducts (B). The following parameters were determined from simulation of the experimental EPR spectrum: DMPO-OOH: aN = 14.15 G, aHβ = 11.31 G and aHγ = 1.24 G, weight: 76%; DMPO-OH: aN = 15.0 G, aH = 14.5 G, weight: 24%. EPR system scan parameters are: microwave power = 20 mW, modulation amplitude = 0.50 G, sweep width = 70 G, receiver gain = 1 x 105, time constant = 81.92 ms, scan time 21 s with 5 scans coadded.