Figure 3 of Yoon, Mol Vis 2011; 17:1839-1849.

Figure 3. Electrospray ionization (ESI) mass spectra of samples of A2E irradiated in the absence and presence of glutathione (GSH). Mixtures of A2E and GSH at indicated concentrations were irradiated at 430 nm for 20 min following which the sample was analyzed by ultraperformance liquid chromatography–mass spectrometry (UPLC/MS). The mass to charge ratio (m/z) of glutathione disulfide (GSSG) is 613.