Fingerprinting metal-containing biomolecules after reductive displacement of iron by gallium and subsequent column-switched LC-ICPMS analysis applied on siderophores.
Column-switching liquid chromatography followed by low-resolution ICPMS was evaluated as a tool for speciation analysis of metal-containing biomolecules. The strategy was applied on siderophores, strong iron chelators of low molecular weight (M(w) < 1500). Prior to the LC-ICPMS analysis, reductive displacement of iron by gallium was performed using ascorbate as the reducing agent to increase the sensitivity. Different experimental conditions during the exchange reaction were tested using ferrichrysin and ferrichrome for evaluation. A reaction time of 30 min and a pH of 3.9 gave an exchange yield of 27 and 83% for ferrichrysin and ferrichrome, respectively. A gradient elution profile was also developed to separate gallium-chelated siderophores on a PGC column. Detection limits for standard solutions of ferrichrysin and ferrichrome in the low-nanomolar range were obtained by monitoring the gallium-69 isotope. The combined use of LC-ICPMS and LC-ESI-MS/MS was also evaluated as a tool to identify unknown metal complexes, here siderophores, in field soil solution samples.
Moberg
My
M
Department of Analytical Chemistry, Uppsala University, PO Box 599, SE-751 24 Uppsala, Sweden.
Nilsson
Eva M
EM
Holmström
Sara J M
SJ
Lundström
Ulla S
US
Pettersson
Jean
J
Markides
Karin E
KE
D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005708:Gallium / Q000032:analysis / Q000737:chemistry*; D007501:Iron / Q000032:analysis / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D017262:Siderophores / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods
D008670:Metals; D017262:Siderophores; D005708:Gallium; D007501:Iron; D001205:Ascorbic Acid