9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABMDMA) is a reagent used to detect singlet oxygen generation. This water-soluble derivative of anthracene can be photobleached by singlet oxygen to its corresponding endoperoxide. This reaction can be monitored spectrophotometrically by recording the decrease in optical density at 400 nm (ABMDMA ex/em max. = 380/407 nm in 0.1 M phosphate pH 7.0).
