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. Author manuscript; available in PMC: 2022 Dec 13.
Published in final edited form as: Biomacromolecules. 2021 Nov 12;22(12):5128–5138. doi: 10.1021/acs.biomac.1c01095

Figure 5. X-Band EPR detection of photogenerated radicals from C-PC at pH 3.0–9.0.

Figure 5.

(A–B) Time-dependent EPR spectra of 2,2,6,6-tetramethylpiperidine (TEMP)/1O2 (A) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) adducts (B) collected under in situ UVA irradiation for the indicated times. The spectra are shifted by an arbitrary offset for clarity. Panels i–iv in (B) are used for the spectral simulations in (C). (C) Experimental (colored lines) and simulated (black lines) EPR spectra of photogenerated DMPO adducts with residuals of the fits reported below. The input spectra are C-PC at pH 3.0 after 30 min irradiation (i); and C-PC at pH 5.0 (ii), 7.0 (iii) and 9.0 (iv) after 20 min irradiation. The symbols mark line components belonging to DMPO–R• (black dots), DMPO–CO2•– (light-blue triangles), DMPO–H• (red diamonds), DMPO–OH• (light-green squares), and an unidentified DMPO–X• (magenta asterisk); see Table S3 for details of spectral simulation. In all cases, the C-PC concentration was 1 mg/ml.