Early detection of colorectal adenocarcinoma: a clinical decision support tool based on plasma porphyrin accumulation and risk factors

Table 4 Chromatographic and spectrometric properties of the analytes involved in heme biosynthesis

Porphyrin	Molecular formula	Theoretical M/Z ratio [M + H]⁺	Experimental M/Z ratio [M + H]⁺	RT [min]
Protoporphyrin IX	C₃₄H₃₄N₄O₄	563.2653	563.2651	6.88
Iron protoporphyrin IX	C₃₄H₃₂FeN₄O₄	616.1768	616.1775	4.48
Biliverdin	C₃₃H₃₄N₄O₆	583.2551	583.2565	2.96
Coproporphyrin I	C₃₆H₃₈N₄O₈	655.2762	655.2775	1.85
Protoporphyrin IX dimethylester	C₃₆H₃₈N₄O₄	591.2966	591.2961	8.06