TABLE 1.

ESI-MS/MS fragmentation of extracted gallium-bound siderophores for P. stutzeri grown under aerobic conditions and for both iron(III)- and gallium-bound reference substances, ferrioxamines B, G, and E, obtained at a collision energy of 40 eV

Loss of amu	Fragment abundancea
	B ref	G ref	G sample	E ref	E sample	Unknown 1 (D2)	Unknown 2b (X1)
−17	+	+	+
−18	+	+	+	+	+	+	+
−35	(+)	(+)	(+)	+	+	+	+
−36	(+)	(+)	(+)	+	+	+	+
−44				+	+	+	+
−46	(+)	(+)	(+)	+	+	+	+
−63				+	+	+	+
−86						+	+
−100	(+)	+	+	+	+	+	+
−117				+	+	+	+
−118	+	+	+
−134				+	+	+	+
−146	+	+	+
−160	+
−186						+	+
−200	+	+	+	+	+	+	+
−203						+
−217	+	+	+	+	+	+
−218		+	+

^a+, major fragment; (+), fragment with low abundance; B ref, G ref, and E ref, ferrioxamine B, G, and E references; G sample and E sample, gallium-bound ferrioxamine G and E samples.

^bWeak spectra due to low concentration.