Dual-scan acquisition for accelerated continuous-wave EPR oximetry.

Statistical analysis reveals that, given a fixed acquisition time, linewidth (and thus pO(2)) can be more precisely determined from multiple scans with different modulation amplitudes and sweep widths than from a single-scan. For a Lorentzian lineshape and an unknown but spatially uniform modulation amplitude, the analysis suggests the use of two scans, each occupying half of the total acquisition time. We term this mode of scanning as dual-scan acquisition. For unknown linewidths in a range [Γ(min), Γ(max)], practical guidelines are provided for selecting the modulation amplitude and sweep width for each dual-scan component. Following these guidelines can allow for a 3-4 times reduction in spectroscopic acquisition time versus an optimized single-scan, without requiring hardware modifications. Findings are experimentally verified using L-band spectroscopy with an oxygen-sensitive particulate probe.