title: Electrochemical reduction of the iodinated contrast medium iomeprol: iodine mass balance and identification of transformation products.
abstract: Potentiostatic-controlled electrochemical reduction of iomeprol was used to deiodinate iomeprol (IMP), a representative of the iodinated X-ray contrast media. The reduction process was followed by product analysis with liquid chromatography-electrospray ionization-tandem mass spectrometry and ion chromatography-inductively coupled plasma-mass spectrometry. The identification is mainly based on the interpretation of the mass fragmentation. The product analysis showed a rather selective deiodination process with the successive occurrence of IMP-I, IMP-2I, IMP-3I, and a transformation product (TP), respectively. The TP was formed from IMP-3I by a further cleavage of an amide bond and release of a (C=O)CHOH group from the side chain of IMP. The iodine mass balance on the basis of IMP and iodide showed a gap of about 26% at the beginning of the electrolysis process which could be completely closed by taking the intermediates IMP-I and IMP-2I into consideration. This means that the major intermediates and the TPs were considered and that the reduction process is a rather selective one to remove organically bound iodine from X-ray contrast media. An attractive application area would be the electrochemical deiodination of X-ray contrast media in urine of patients or hospital effluents.
authors.affiliation: Engler-Bunte-Institut, Universität Karlsruhe (TH), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. c.zwiener@kit.edu
authors.forename: Christian
authors.initials: C
authors.lastname: Zwiener
authors.forename: Thomas
authors.initials: T
authors.lastname: Glauner
authors.forename: Jochen
authors.initials: J
authors.lastname: Sturm
authors.forename: Michael
authors.initials: M
authors.lastname: Wörner
authors.forename: Fritz H
authors.initials: FH
authors.lastname: Frimmel
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D003287:Contrast Media / Q000737:chemistry*; D004563:Electrochemistry; D007455:Iodine / Q000737:chemistry*; D007479:Iopamidol / Q000031:analogs & derivatives* / Q000737:chemistry; D008970:Molecular Weight; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007455:Iodine; D007479:Iopamidol