Development of a spectrophotometric determination of siderophores using flow-injection analysis

A method has been developed for the spectrophotometric determination of siderophores using flow-injection analysis (FIA) based on the reaction of siderophores with the ternary complex Eriochrome Cyanine R-Fe(III)-cetyltrimethylammonium bromide. 2,3-Dihydroxybenzoic acid, 2,3-dihydroxynaphthalene, and tolypocine were used as the model iron-binding ligands. The calibration curve for one of the siderophores (tolypocine) is linear in the concentration range 2.6 x 10(-6)-1.5 x 10(-4)M. The determination limit (10sigma) for tolypocine was 2.6 x 10(-6)M. The applicability of the method was demonstrated on the determination of the complexation ability of siderophores produced by some entomopathogenic fungi. Samples can be analysed at a rate of 30 samples per hour.