title: Trace determination of gadolinium in biomedical samples by diode laser-based multi-step resonance ionization mass spectrometry.
abstract: The application of high-resolution multi-step resonance ionization mass spectrometry (RIMS) to the trace determination of the rare earth element gadolinium is described. Utilizing three-step resonant excitation into an autoionizing level, both isobaric and isotopic selectivity of >10(7) were attained. An overall detection efficiency of approximately 10(-7) and an isotope specific detection limit of 1.5 x 10(9) atoms have been demonstrated. When targeting the major isotope (158)Gd, this corresponds to a total Gd detection limit of 1.6 pg. Additionally, linear response has been demonstrated over a dynamic range of six orders of magnitude. The method has been used to determine the Gd content in various normal and tumor tissue samples, taken from a laboratory mouse shortly after injection of gadolinium diethylenetriaminepentaacetic acid dimeglumine (Gd-DTPA), which is used as a contrast agent for magnetic resonance imaging (MRI). The RIMS results show Gd concentrations that vary by more than two orders of magnitude (0.07-11.5 microg mL(-1)) depending on the tissue type. This variability is similar to that observed in MRI scans that depict Gd-DTPA content in the mouse prior to dissection, and illustrates the potential for quantitative trace analysis in microsamples of biomedical materials.
authors.affiliation: Institüt für Physik, Johannes Gutenberg-Universität Mainz, Germany. klaus.blaum@cern.ch
authors.forename: K
authors.initials: K
authors.lastname: Blaum
authors.forename: C
authors.initials: C
authors.lastname: Geppert
authors.forename: W G
authors.initials: WG
authors.lastname: Schreiber
authors.forename: J G
authors.initials: JG
authors.lastname: Hengstler
authors.forename: P
authors.initials: P
authors.lastname: Müller
authors.forename: W
authors.initials: W
authors.lastname: Nörtershäuser
authors.forename: K
authors.initials: K
authors.lastname: Wendt
authors.forename: B A
authors.initials: BA
authors.lastname: Bushaw
mesh_terms: D000818:Animals; D003287:Contrast Media; D005682:Gadolinium / Q000032:analysis*; D007554:Isotopes / Q000032:analysis; D007834:Lasers; D008279:Magnetic Resonance Imaging; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000737:chemistry / Q000473:pathology; D009928:Organ Specificity; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D007554:Isotopes; D005682:Gadolinium