. 2020 Feb 26;5(9):4626–4635. doi: 10.1021/acsomega.9b04322

Table 1. Identification of Prodiginine Pigments in P. rubra Strain PS1^a.

peak #	identification	t_R (min)	λ_max (nm)	molecular ion (m/z)	product ion (m/z)	CE (V)	compound formula
1	2-methyl-3-propyl prodiginine	1.66	532	296.1 [M + H]⁺	92.0 [M – 204]⁺	–35	C₁₈H₂₁N₃O
					252.2 [M – 44]⁺	–30
					281.0 [M – 15]⁺	–20
2	2-methyl-3-butyl prodiginine	1.94	531	310.2 [M + H]⁺	92.1 [M – 218]⁺	–49	C₁₉H₂₃N₃O
					252.2 [M – 58]⁺	–31
					295.3 [M – 15]⁺	–22
3	cycloprodigiosin	2.16	537	322.4 [M + H]⁺	147.2 [M – 175]⁺	–32	C₂₀H₂₃N₃O
					292.2 [M – 30]⁺	–33
					307.2 [M – 15]⁺	–24
4	prodigiosin	2.52	537	324.4 [M + H]⁺	92.2 [M – 232]⁺	–53	C₂₀H₂₅N₃O
					252.1 [M – 72]⁺	–33
					309.5 [M – 15]⁺	–23
5	2-methyl-3-hexyl prodiginine	3.00	535	338.5 [M + H]⁺	92.2 [M – 246]⁺	–51	C₂₁H₂₇N₃O
					252.1 [M – 86]⁺	–33
					323.2 [M – 15]⁺	–23
6	2-methyl-3-heptyl prodiginine	3.69	536	352.5 [M + H]⁺	92.2 [M – 260]⁺	–52	C₂₂H₂₉N₃O
					252.2 [M – 100]⁺	–34
					337.3 [M – 15]⁺	–25

Note: Product ions were obtained at the optimized collision energy (CE) determined by multiple reaction monitoring (MRM).

Table 1. Identification of Prodiginine Pigments in P. rubra Strain PS1a.