Figure 3
From: Noninvasive monitoring of bilirubin photoisomer excretion during phototherapy
Reverse photoisomerization in LC–MS/MS. MRM spectra of purified LR and urine. The retention times of MBR, ZZ-BR, and LR were 17.22, 16.53, and 2.00 min, respectively. As MBR was used as an internal standard, a signal at 17.22 min was observed in all analyses. (a) Before blue light exposure. All MRM spectra showed the concentration of LR but not that of ZZ-BR. (b) After blue light exposure. ZZ-BR (16.53 min) appeared with apoUnaG in both purified LR and urine. Without apoUnaG, however, only LR decreased, and ZZ-BR was not detected, even after exposure to blue light. LC–MS/MS, liquid chromatography–mass spectrometry; MRM, multiple reaction monitoring; MBR, mesobilirubin; ZZ-BR, ZZ-bilirubin; LR, lumirubin.
